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W7EET
10-10-2011, 04:10 PM
Hi Folks:
Yes, I was curious if any Electrical Engineer has a HF amplifier circuit board and parts for the new MRFE6VP61K25h mosfet? If so I would like to have a copy of the circuit board and a list of parts. IF not, I would like to have an electrical engineer design one with two of these mosfets and also with one mosfet. Also, consider, operating frequenices of 160-6meters. With two mosfet's one can turn the power down to max operating power acc/w FCC rules and reg's and loaf along.
Contact me:
w7eet@arrl.net
Thank you,
Rich:)

W9GB
10-10-2011, 05:18 PM
I would like to have a copy of the circuit board and a list of parts.
Rich -

Evaluation baords (with parts lists) are available directly from these RF device manufacturers (Freescale - TX / AZ; NXP - Japan) --
for the experienced DIY Builder.

IF you are looking for a "Heathkit style" kit of parts and assembly instructions -- NO, I have not seen such a kit.
Given the current global economic conditions (prospective buyers) -- I do not expect to see such a kit in the near future.


IF not, I would like to have an electrical engineer design one with two of these mosfets and also with one MOSFET.

Your request analogy is: Ford Motors has a new crate V-8 motor with great horsepower and you desires someone to build a specific car (racing/NASCAR or pleasure).
You are looking for a Chip Foose ... but are unsure how much that would cost.

There are qualified RF professionals who could build to a spec, with sufficent $$$ (Tom, W8JI; Paul, WD7S; etc.) -- there are
also a large number of "want-a-bees" builders -- who will gladly take your money -- but you would likely never receive what you desired.

There are also some current mfg. (Elecraft, Alpha, etc.) that may entertain your offer -- but that investment (> $75,000) will be more than you likely desire to make.
==

BTW, the BIGGEST issue with an amplifier build of this size (RF wattage output) is proper Thermal handling / dissipation.
Electrical Engineers are not always well versed in proper Thermodynamics / Heatsink designs. :-)
Commercial products are usually produced by a TEAM of experienced engineers (mechanical, electrical, thermal) from various disciplines for optimal design.

w9gb

W7EET
10-10-2011, 05:51 PM
Reply to w9gb:
Freescale has a pc board only for VHF test models and in fact someone has already built one for VHF amplifier with boards and parts. However, this will not perform on HF. I did not ask for a electrical engineer to rebuild Ford company. I am more than wiser than to let some scammer to take my money. There are a numerous of Electrical engineers that are ham radio operators out there that has cad on their computers to design a HF amp for this particular mosfet. Ham radio is for good will not to profit by other ham radio operators. So, what have I got in mind is to have an challange to create something to pass onto other hamradio operators to build from scratch and create one's own heathkit. Also, learn while creating this HF RF Amplifier. I am no newbe to Electronics since my field is Radar and aviation Electronic repair.
Rich/W7EET

W8JI
10-10-2011, 07:48 PM
Hi Folks:
Yes, I was curious if any Electrical Engineer has a HF amplifier circuit board and parts for the new MRFE6VP61K25h mosfet? If so I would like to have a copy of the circuit board and a list of parts. IF not, I would like to have an electrical engineer design one with two of these mosfets and also with one mosfet. Also, consider, operating frequenices of 160-6meters. With two mosfet's one can turn the power down to max operating power acc/w FCC rules and reg's and loaf along.
Contact me:
w7eet@arrl.net
Thank you,
Rich:)

I wish Freescale would tone down their rhetoric.

The FET on U-tube is in pulse service. That basically is a 600 watt SSB FET.

If you look at the actual data sheet, it slides into gain compression at 600-700 watts at 85 degrees C on the case. Their big power ratings come from having the case at -30C.

If you use one FET and can manage to get the heat out, you have the electrical equal of an ALS-600 in every way, including SWR tolerance.

Two FET's, if you can get the heat out, will provide about 1200 watts or so with proper cooling.

The 65:1 VSWR and 1200 watts come from pulse duty service, and probably with a current limited supply.

That FET is the electrical equal of (4) MRF150 except all the heat is in one place.

73 Tom

W8JI
10-10-2011, 07:48 PM
Hi Folks:
Yes, I was curious if any Electrical Engineer has a HF amplifier circuit board and parts for the new MRFE6VP61K25h mosfet? If so I would like to have a copy of the circuit board and a list of parts. IF not, I would like to have an electrical engineer design one with two of these mosfets and also with one mosfet. Also, consider, operating frequenices of 160-6meters. With two mosfet's one can turn the power down to max operating power acc/w FCC rules and reg's and loaf along.
Contact me:
w7eet@arrl.net
Thank you,
Rich:)

I wish Freescale would tone down their rhetoric.

The FET on U-tube is in 20% duty cycle 100uS pulse service. That basically is a 600 watt SSB FET.

If you look at the actual data sheet, it slides into gain compression at 600-700 watts at 85 degrees C on the case. Their big power ratings come from having the FET case at -30C and using low duty cycle pulse service. I designed a medical device that ran two MRF 150's at 1200 watts pulse serve, and would handle near-infinite SWR (open or shorted load with a very short feedline attached). There is no magic to 1200 watts pulse.

If you use one FET and can manage to get the heat out, you have the electrical equal of an ALS-600 in every way, including SWR tolerance.

Two FET's, if you can get the heat out, will provide about 1200 watts or so if you can supply enough cooling.

The 65:1 VSWR and 1200 watts they show on the video comes from pulse duty service, and probably with a current limited supply.

That FET is the electrical equal of (4) MRF150 except all the heat is in one place.

73 Tom

W9GB
10-10-2011, 08:01 PM
So, what have I got in mind is to have an challenge to create something to pass onto other hamradio operators to build from scratch and create one's own heathkit.
Also, learn while creating this HF RF Amplifier.
Rich -

Understood. BTW, Elecraft is the company that is trying to fill the void left by Heathkit's departure --
their designs have been better than many of the kits produced at Benton Harbor.
The Elecraft KPA-500 is an impressive amplifier design .. in a small package .. and at a price point (and quality level) that should discourage Eastern Asian copies.

As Tom W8JI noted, the YouTube video has likely created the wrong impression (rhetoric) of Freescale's (and NXP's) newer RF devices.


There are a numerous of Electrical engineers that are ham radio operators out there that have CAD on their computers
to design a HF amp for this particular MOSFET.
Rich -

You seemed to miss my point.
Designing a carrier PC board is just ONE STEP of the overall design toward the final product.

My concern (for any final design) continues to be proper cooling -- now you have the equivalent of 4 MRF 150 RF devices --
in a concentrated surface area (footprint) -- not dispersed at 4 points of heat generation -- that will produce significant heat (wasted energy of conversion process).
The next question is DC power requirements and then the overall footprint of the final product design.

From my perspective, we are still missing the point Steve Jobs (sk) had been making for the past 30 years,
you have to LOOK at the entire system or device that you are creating and its usability (ease of use, on aspect) for the end user.

Some amateurs are experimenting (and creating initial DIY builds) with these new devices (Freescale or NXP) -- BUT I have not
seen any openly available designs/kits from these efforts -- YET.
==
While MFJ has an assembled solid-state unit in this RF output class,
Elecraft has yet to produce/release a 1.0 - 1.5 kW RF output amplifier ........ kit or assembled.

A competition is always possible -- what is the end point reward for the build ?

w9gb

W7EET
10-10-2011, 08:35 PM
I have been a ham for 40 years and have built many ham related equipment. From vaccum tubes to solid state. This newer type devices is a another ball park. The main thing is the board with the mosfet on it that requires the most attention for an engineer design. This I can not do or make. The rest of the circuity I can manage to finish. Like the cooling heat sinks, safety circuits, filters, power supply and so on. I called freescale and ask them about the mosfet and highly questioned them on the power out. They told me this mosfet will cw at 1200 watts. For how long ??? So this will be a experimental circuit and there is someone already has a 1200 watt VHF 2 meter amplifier in use. Using only one mosfet. When I grew up, this is one of the many things as a hobby is to make and build one's own equipment. So, is this old school training,,,yes! and I enjoy it very much.
Rich/W7EET

WB2WIK
10-10-2011, 10:33 PM
I have been a ham for 40 years and have built many ham related equipment. From vaccum tubes to solid state. This newer type devices is a another ball park. The main thing is the board with the mosfet on it that requires the most attention for an engineer design.

I'm sure you know the board wouldn't have the MOSFET on it, at all. The FET would mount directly to the heat sink; the board would "surround" the FET with additional circuitry and provide the I-O paths and DC current paths.

Since the device in question is dissipating 657.4W/square inch (assuming the ~75% efficiency claimed) the HS would need to be extremely good, as well as fan cooled, unless it was in a refrigeration system (maybe possible).

If I could get a couple of devices for free I might try it; but to risk degrading them to carbon during trials and having to pay for them would be a bit sad.;)

AF6LJ
10-10-2011, 10:48 PM
I'm sure you know the board wouldn't have the MOSFET on it, at all. The FET would mount directly to the heat sink; the board would "surround" the FET with additional circuitry and provide the I-O paths and DC current paths.

Since the device in question is dissipating 657.4W/square inch (assuming the ~75% efficiency claimed) the HS would need to be extremely good, as well as fan cooled, unless it was in a refrigeration system (maybe possible).

If I could get a couple of devices for free I might try it; but to risk degrading them to carbon during trials and having to pay for them would be a bit sad.;)

That amplifier is a really good candidate for ether water or vapor phase cooling.
For the few percent lower thermal resistance you would pick up it might be worth it to silver plate the copper heat spreader.
Regardless one is going to spend as much on the cooling system as they are going to spend on FETs.

WB2WIK
10-10-2011, 10:57 PM
That amplifier is a really good candidate for ether water or vapor phase cooling.
For the few percent lower thermal resistance you would pick up it might be worth it to silver plate the copper heat spreader.
Regardless one is going to spend as much on the cooling system as they are going to spend on FETs.

Yep. Semiconductors can handle a lot of power as long as we keep the material cool and don't melt the internal wire bonds.:o

They're claiming 0.15C/W for Rthj-c and derate MTTF with temperature. Keeping the silicon down to 150C max at full power on CW is going to be quite a trick.

AF6LJ
10-10-2011, 11:05 PM
Yep. Semiconductors can handle a lot of power as long as we keep the material cool and don't melt the internal wire bonds.:o

They're claiming 0.15C/W for Rthj-c and derate MTTF with temperature. Keeping the silicon down to 150C max at full power on CW is going to be quite a trick.

Not only that; as Tom pointed out for linear service they are really only good up to about 600W out. per device. Two amplifiers combined would give you a nice legal limit amplifier.

I wonder how many of those I would have to blow up before I had a stable amplifier. :)

I have another beef.......
I really don't 50V is high enough Voltage for devices in that power class.
I would like to see some 250V FETs in that power class.

W7EET
10-10-2011, 11:28 PM
wb2wik:
Hi, I use to work in a two-way radio shop and radar equipment. I already know about the mounting of solid state devices on heat sinks. I did more than a count on my fingers...and then some. I was considering using 1/2 copper plate to a very large alum heat sink. Of course, I would have to take it to a machine shop to have them resurface (milling machine) to match them both for maxium heat transfer. I was thinking of using apx 6 inches by 12 inch heat sink per mosfet. Having two split modules using baluns. Running a squirrel cage fan for cooling and use a thermal switch to turn on the fan when the temp rises and then turn off when temp drops to a certain. degree of temperature. AND, here I am thinking out loud.
Rich/W7EET

G4COE
10-10-2011, 11:39 PM
Here's the data sheet (http://www.google.co.uk/url?sa=t&source=web&cd=1&ved=0CBsQFjAA&url=http%3A%2F%2Fcache.freescale.com%2Ffiles%2Frf_ if%2Fdoc%2Fsupport_info%2FRDMRFE6VP61K25H_VHF_BCAS T.pdf&rct=j&q=MRFE6VP61K25h%20%20power%20amp%20schematic&ei=_oCTTpH3NMeY8QO0hcD5Bg&usg=AFQjCNECsv6CJBT5WCV88K47LmZb-rqBbQ&cad=rja) if ya need it in pdf format and here is a Utube video. (http://www.youtube.com/watch?v=-EACUpIhpac)

Dave

AF6LJ
10-10-2011, 11:48 PM
Not only that; as Tom pointed out for linear service they are really only good up to about 600W out. per device. Two amplifiers combined would give you a nice legal limit amplifier.

I wonder how many of those I would have to blow up before I had a stable amplifier. :)

I have another beef.......
I really don't 50V is high enough Voltage for devices in that power class.
I would like to see some 250V FETs in that power class.

This device is a little different from the one that was discussed here two months ago.
That one had in the datasheet IMD figures and was intended for linear operation.

W6RZ
10-10-2011, 11:52 PM
1KW 222 MHz LDMOS Amplifier using the MRFE6VP61K25H.

http://w6pql.com/1kw_222mhz_ldmos_amplifier.htm

1KW 2M LDMOS Amplifier using the MRFE6VP61K25H.

http://w6pql.com/1_kw_2m_ldmos_amplifier.htm

WB2WIK
10-11-2011, 12:15 AM
wb2wik:
Hi, I use to work in a two-way radio shop and radar equipment. I already know about the mounting of solid state devices on heat sinks. I did more than a count on my fingers...and then some. I was considering using 1/2 copper plate to a very large alum heat sink. Of course, I would have to take it to a machine shop to have them resurface (milling machine) to match them both for maxium heat transfer. I was thinking of using apx 6 inches by 12 inch heat sink per mosfet. Having two split modules using baluns. Running a squirrel cage fan for cooling and use a thermal switch to turn on the fan when the temp rises and then turn off when temp drops to a certain. degree of temperature. AND, here I am thinking out loud.
Rich/W7EET

A centrifugal blower shouldn't be required, as blowing air across a heat sink creates virtually no back pressure. A high volume axial fan would normally do a much better job of cooling in an application like this.

Milling a copper heat spreader sounds like a great idea; you'd want very, very good flatness.

I can believe all sorts of claims about these things in pulse service or even SSB, but "CW" is a whole 'nother story! I think Freescale interpreted "CW" to mean "carrier power, of very short duration" as opposed to the Alpha Power definition, which is "continuous carrier, with a brick on the key, and it can do this forever." Hams have different interpretations.

Once the matching and decoupling details are worked out (and for HF it's more complex than for VHF, since single-band VHF amps only need to work over a miniscule percentage of the operating frequency; HF amps might have to work over more than a decade) on a prototype, I'd be very tempted to eliminate the aluminum heatsink and just circulate DI water through a copper block using a small pump and heat exchanger. It's simply more efficient. I think that's why we have this system in cars.:o

AC0OB
10-11-2011, 03:30 AM
FreeScale hosted a seminar in which they provided some data:

Example: MRFE6VP6K1K25KH, operating at 1.1kW, with 80% efficiency.
IDrain = 1100W/(80% x 50V) = 27.5A
MRFE6VP61K25H have Rth of 0.15W/C, Case temperature = 80C
Dissipated power = PDC – Pout + Pin
Dissipated power = 50V*27.5A – 1100W +4W = 279W
Trise = 279W * 0.15W/C = 42 C
TJ = Trise + Tcase = 42 /C + 80C = 122C

They are currently sampling certain "61K" series of LDMOS MOSFETS

They also stated they will loan development/application circuit boards to qualified companies and individuals.

Phil - AC0OB

W7EET
10-11-2011, 04:06 AM
Hey guys:
Just do not rely on one data sheet for this type of LDMOS MOSFET. There is about 10 variations of this device for power output. Some are lower power out or pulsed for radar applications and there is two types with the full cw power out of 1200 watts out of the 10 under the data sheet. It may have something to do with the wire size to the internal part of the silicon connection to handle the current. The VHF 2 meter amplifier has a poor circuit design on the pc board. The mounting for the balun has two pieces of coax instead of using a pc inductive circuit trace layout. PC circuit inductive balun would be more stable than using coax. The website is above from my listing under W6RZ listing. I will see what I can come up with to prove my point.
Rich/W7EET

W8JI
10-11-2011, 04:18 AM
The data sheet is here:

DATA sheet (http://cache.freescale.com/files/rf_if/doc/data_sheet/MRFE6VP61K25H.pdf)

If you go to page 2 you will see this is primarily a pulsed device with an average power of 250 watts. The 65:1 VSWR is for 250 watts average power, and 1250 watts pulsed power. On page 5 you will see in pulsed duty gain flattens out at about 700 watts peak power, and the device is not particularly linear.

I'm not sure how this device stacks up in linear service, but I can get similar pulse performance out of two MRF150 FET's. I can get about 1200 watts pulse power from a pair of MRF150's.

Based on the curves on page 5, this device does not look too linear.

73 Tom

W7EET
10-11-2011, 04:27 AM
Tom:
There is about 10 different varieties of this device. From pulse, low power out, to full cw of 1200 watts. Here is a link of this new type of continues duty or 100% duty cycle.
http://www.rell.com/pages/Product-Details.aspx?productId=966540

Note: the last three letters on the end other part number will give the correct classification to the data of operation.
so, beware of the part numbers to the data sheet so everyone here will be on the right page for the correct device.
Rich/W7EET

W6RZ
10-11-2011, 06:08 AM
The last three letters just specify the reel option and package type. From page 12 of the data sheet:

R5 Suffix = 50 Units, 56 mm Tape Width, 13 inch Reel.

The R6 option appears to be 150 units on a reel.

The S option is just the package type. The MRFE6VP61K25H is in the NI-1230 package that has "ears" to bolt the device to a PCB. The MRFE6VP61K25HS is in a NI-1230S package that does not have "ears". Both packages are shown in the data sheet. The Digikey website has a picture of both packages.

http://www.digikey.com/us/en/ph/Freescale/rugged-rf.html

Aside from the package types, there is only one version of the MRFE6VP61K25H.

BTW, the W6PQL links I posted were more to show the spreader and heatsink he used.

KB4QAA
10-11-2011, 06:11 AM
I agree. Can only find three model numbers and difference is packaging.

W6RZ
10-11-2011, 06:38 AM
The 2-meter amplifier app note has detailed linearity measurements.

http://cache.freescale.com/files/rf_if/doc/support_info/RDMRFE6VP61K25H_2MTR_AMATEUR.pdf?fpsp=1

W7EET
10-11-2011, 03:08 PM
Nice link W6RZ:
I really liked the thermal and the charts input and output. I can not hardly wait to see a module and circuit board built for HF. This device only cost around $350 bucks (american money) each. One of the other comments was the power supply voltage have it around 60 volts so it would lower the current draw. The power supply could be 60 vdc at 75 amps.
Rich/W7EET

AF6LJ
10-11-2011, 03:15 PM
The 2-meter amplifier app note has detailed linearity measurements.

http://cache.freescale.com/files/rf_if/doc/support_info/RDMRFE6VP61K25H_2MTR_AMATEUR.pdf?fpsp=1

you can see the effects of gain compression on IMD in the two tone tests as Various power output levels.

Thermal issues remain the biggest design issue in my opinion.

W8JI
10-11-2011, 03:42 PM
The 2-meter amplifier app note has detailed linearity measurements.

http://cache.freescale.com/files/rf_if/doc/support_info/RDMRFE6VP61K25H_2MTR_AMATEUR.pdf?fpsp=1

That data confirms and agrees with what the other data sheets show. IMD falls apart at about 600-700 watts. This device is very similar to four MRF150 devices. One of these devices would make a good 600-700 watt SSB amplifier if heat can be properly manged.

73 Tom

W8JI
10-11-2011, 03:53 PM
Nice link W6RZ:
I really liked the thermal and the charts input and output. I can not hardly wait to see a module and circuit board built for HF. This device only cost around $350 bucks (american money) each. One of the other comments was the power supply voltage have it around 60 volts so it would lower the current draw. The power supply could be 60 vdc at 75 amps.
Rich/W7EET

I'd be a little careful at running a 50 volt device with a rated drain-source breakdown of 125 volts at 60 volts DC. You are heading for problems, because a ~3:1 SWR or less of the wrong phase angle could ruin the device in a heartbeat.

Let me give you an example. With a vacuum tube, known to be rugged, a tube with a 6000-volt breakdown voltage is marginally reliable at 2500 volts anode supply voltage.

You can see mismatched drain voltages here:

http://www.w8ji.com/demonstation.htm



Think about what you are doing before you do it. In push-pull, or in single ended in linear service, peak drain voltage is about 1.8 times DC supply voltage. This is with a flat SWR. That means at 60 volts you are running the devices around 108 volts peak voltage with a perfect load. You have virtually zero headroom.

Don't be fooled by the 65:1 VSWR claims, because every device rating limits the real-world SWR that can be tolerated. The MRF150 for example is rated at a 30:1 SWR at any phase angle, but in the real world as little as a 2:1 SWR can ruin one at full power if drain voltage is set at 60 volts. It, like the freescale, is also a 125 volt breakdown device. Most VSWR ratings are about how they are cooked up, not what they really are in the real world.

Any practical amplifier is nothing like a pulsed test fixture.

W7EET
10-11-2011, 07:13 PM
ref to W8JI:
Ok, I will consider that very much about the voltage drain. That is a good point so make a 50 vdc at 75 amp linear supply. Far as heat,, I am thinking of a heat sink of 6 inches by 12 inches per device. Using 1/2 copper plate plus at least a 2 inch heat fins on the alum heat sink. The copper plate and the alum heat sink will be bolted together. This should be efficient enough to keep the each of the devices cool enough. So this means two separate heat sinks with split baluns for the feed and combine out. Plus the cooling fans with thermal turn on and off.
Rich/W7EET

W9GB
10-11-2011, 10:07 PM
Far as heat,, I am thinking of a heat sink of 6 inches by 12 inches per device.
Using 1/2 copper plate plus at least a 2 inch heat fins on the alum heat sink. The copper plate and the alum heat sink will be bolted together.
This should be efficient enough to keep the each of the devices cool enough.
Of course, I would have to take it to a machine shop to have them resurface (milling machine) to match them both for maxium heat transfer.

Rich -

That is the right approach - using a copper spreader and properly machining the mating surfaces of the copper spreader and aluminum heat sink
IF you get a patient machinist ... and polish after to a mirror finish ... you will have fewer heat transfer issues :-)

There are a number of inexpensive water cooled solutions -- thanks to the uProcessor "overclockers".
IBM surplus would have been another option in late 1990s ... when they migrated some computer systems to air cooled.

w9gb

W6RZ
10-11-2011, 11:58 PM
That data confirms and agrees with what the other data sheets show. IMD falls apart at about 600-700 watts. This device is very similar to four MRF150 devices. One of these devices would make a good 600-700 watt SSB amplifier if heat can be properly manged.

73 Tom
It's difficult to get a real apples to apples comparison, but doesn't an ALS-600 (a 4X MRF-150 design) have 3rd order IMD products at about -30 dB at 600 watts output? The MRFE6VP61K25H amp can do 900 watts at that IMD level.

W7EET
10-12-2011, 02:01 AM
to W6RZ:
Just think of changing all those MRF-150's by soldering them one at a time, compare to one MRFE6V. Also, Just think of this , one MRFE6V easily has an output of 900 watts with the same IMD rating as a ALS-600 with only 600 watts compare with two modules of MRFE6V with a easy 1800 watts in which can be turned down for a less IMD rating 1500 watts. I am starting to like this more and more...
Rich/W7EET

W7EET
10-12-2011, 05:46 PM
So, I am going to ask again:
Is there an electrical engineer out there that can design a circuit board for this kind of mosfet?if so, please contact me. This is for the goodwill of ham radio and to help other fellow ham radio operators in building a solid state HF amp.
Rich/W7EET
email:w7eet at arrl.net

W8JI
10-12-2011, 07:17 PM
to W6RZ:
Just think of changing all those MRF-150's by soldering them one at a time, compare to one MRFE6V. Also, Just think of this , one MRFE6V easily has an output of 900 watts with the same IMD rating as a ALS-600 with only 600 watts compare with two modules of MRFE6V with a easy 1800 watts in which can be turned down for a less IMD rating 1500 watts. I am starting to like this more and more...
Rich/W7EET

Here are the real differences:

Four FET's spread the heat around and make cooling easier,

One FET makes a VHF layout much easier, and higher efficiency when push-pull

The one FET you are discussing is about 600-700 watts at the same IMD as 4x MRF150. It gets pretty dirty for SSB use at 900 watts. If you want to allow a degradation in IM, the MRF150 can be pushed higher too. TWO MRF150, in pulse service, can run 1100 watts or more. In SSB service, the transistor you speak of is about equal in power and distortion to four MRF150.

The one FET does have fewer solder connections, but also if it fails you can be sure it is a full cost replacement

There is a decided advantage to a single package at VHF and higher in push pull systems, because the sources are common with virtually no lead length. This greatly improves VHF performance. As a matter of fact all the high power VHF or UHF amps I have done use single package FET's. The additional expense of cooling doesn't matter if performance is better.

At HF, I would never use a single high power package. The reason is one of cost, since performance is about equal regardless of path length between sources.

A good solid state layout and bill of material, for a PA section that is reliable and stable, takes weeks of time if the person is experienced. It would probably cost $2000 or more in parts, plus that time. That is just the starting point. There is also packaging, metering, protection systems, harmonic filters, the air system, and testing.

There would have to be a milled and polished copper heat spreader, mated to a milled and polished heat sink or heat exchanger, to get the heat out of that one point. It takes me about a day to get a heat sink and spreader right, because I have a manual milling machine.

What would a person get for this work? Would he get machining time with his $15,000 milling machine paid for? Parts locating time? Legal limit solid state amps are not like slapping a pair of $20 813's on a pie tin and using a hamfest tank circuit.

WB2WIK
10-12-2011, 08:37 PM
I think Freescale would do well to create an HF amp design on their own and publish an App Note or Engineering Bulletin showing what they did, the PCB Gerber file, parts list and placement diagram, and test results; this is what Motorola always did for many years and it helped sell a lot of RF transistors. Heck, it's kept CCI in business for decades!:o

NL7W
10-12-2011, 09:30 PM
I agree. Then, Heathkit should follow through with kits.

I'm waiting...


I think Freescale would do well to create an HF amp design on their own and publish an App Note or Engineering Bulletin showing what they did, the PCB Gerber file, parts list and placement diagram, and test results; this is what Motorola always did for many years and it helped sell a lot of RF transistors. Heck, it's kept CCI in business for decades!:o

AF6LJ
10-12-2011, 09:36 PM
I second the Steve's comment and agree with Steve's statement regarding an app note on that device used in HF linear amplifier applications.

W8JI
10-12-2011, 09:42 PM
It's difficult to get a real apples to apples comparison, but doesn't an ALS-600 (a 4X MRF-150 design) have 3rd order IMD products at about -30 dB at 600 watts output? The MRFE6VP61K25H amp can do 900 watts at that IMD level.

I don't know where you get that data from.

Worse case on the worse band, the ALS600 is about -35dB PEP at 600 watts biased at 100mA.

I think the ARRL measured -37dB PEP worse case on worse band. It'll be in that area.

I wouldn't use an amplifier only -30dB PEP at home on a big antenna, ever.

WB2WIK
10-12-2011, 10:06 PM
Worse case on the worse band, the ALS600 is about -35dB PEP at 600 watts biased at 100mA.

I think the ARRL measured -37dB PEP worse case on worse band. It'll be in that area.


That's true, that's what they measured:

From the ARRL product review on the ALS-600:

"Figure 1—Worst-case spectral display of
the Ameritron ALS-600 amplifier during
two-tone intermodulation distortion
testing. The worst-case third-order
product is approximately 37 dB below
PEP output, and the worst-case fifthorder
product is approximately 40 dB
down. The amplifier was being operated
at 500 W at 14.020 MHz."

W7EET
10-12-2011, 10:12 PM
There is a machine shop near by here. It will cost around 40 to 50 bucks to have the metal milled and that is two heat sinks and drilled and tapped. The pc boards will cost around 100 bucks for both and the balun transformers will be around 200 dollars plus the rest of the resistors and caps. The two mosfets will be around 500 to 700 for both. Plus I could make my own design for replacement like adding quick disconnects of connectors for replacement. On a als-600 by amertron costs around 150 dollars for shipping one way so there and back is 300 dollars plus repairs of 4 MRF-150 costs around 400 dollars including labor + shipping equals to 700 dollars to replace those transistors. So which is cheaper, replacing one mosfet or 4 transistor and possibly ruining pc board. Believe me, it is easier to replace one than 4 of them. I have done it...
I just want someone to step-up and design a pc board so I can share the project with others. That is the ham radio way of doing things.
Rich/W7EET

AF6LJ
10-12-2011, 10:28 PM
W7EET;
From a pragmatic perspective.
Risking $500-$700 on transistors in a design that has only proven itself in one prototype is really a crap shoot. Input VSWR, temperature, and other factors can effect stability.

Furthermore;
protection circuits are needed which your outline above doesn't include.
What you have described as an amplifier would be only safe being run driven through a pad and the output into a dummy load.

just my two cents.

WB2WIK
10-12-2011, 10:55 PM
W7EET;
From a pragmatic perspective.
Risking $500-$700 on transistors in a design that has only proven itself in one prototype is really a crap shoot. Input VSWR, temperature, and other factors can effect stability.

Furthermore;
protection circuits are needed which your outline above doesn't include.
What you have described as an amplifier would be only safe being run driven through a pad and the output into a dummy load.

just my two cents.

It's certainly more challenging to build an amp that covers three or four octaves (80-10m or 160-10m) than it is to cover a small slice of VHF spectrum. I'd want to include thermal monitoring (at the device, not somewhere else on the heat sink) and possibly other monitors. The input and output transformers would be on the PA board but the output filters could be a different board for ease of service.

I'd love to see Freescale themselves tackle this and then come up with an app note showing all the details, like Motorola and others always did. There may be a reason their common app note is a VHF amp and not HF.

W6RZ
10-12-2011, 11:05 PM
I don't know where you get that data from.

Worse case on the worse band, the ALS600 is about -35dB PEP at 600 watts biased at 100mA.

I think the ARRL measured -37dB PEP worse case on worse band. It'll be in that area.

I wouldn't use an amplifier only -30dB PEP at home on a big antenna, ever.
I found it in this article.

http://www.funkbox.ch/als-600.pdf

W8JI
10-12-2011, 11:07 PM
There is a machine shop near by here. It will cost around 40 to 50 bucks to have the metal milled and that is two heat sinks and drilled and tapped. The pc boards will cost around 100 bucks for both and the balun transformers will be around 200 dollars plus the rest of the resistors and caps. The two mosfets will be around 500 to 700 for both. Plus I could make my own design for replacement like adding quick disconnects of connectors for replacement. On a als-600 by amertron costs around 150 dollars for shipping one way so there and back is 300 dollars plus repairs of 4 MRF-150 costs around 400 dollars including labor + shipping equals to 700 dollars to replace those transistors. So which is cheaper, replacing one mosfet or 4 transistor and possibly ruining pc board. Believe me, it is easier to replace one than 4 of them. I have done it...
I just want someone to step-up and design a pc board so I can share the project with others. That is the ham radio way of doing things.
Rich/W7EET

Hi Rich,

Steve's suggestion is really about the best you can hope for, and the only one that makes any sense at all. Freescale can pay to have it done, or perhaps they can do it internally.

Sue, what's the rate around where you are for a RF engineer that can do that?

Here is mid-Georgia, it's about $100/hr.

73 Tom

AF6LJ
10-12-2011, 11:09 PM
It's certainly more challenging to build an amp that covers three or four octaves (80-10m or 160-10m) than it is to cover a small slice of VHF spectrum. I'd want to include thermal monitoring (at the device, not somewhere else on the heat sink) and possibly other monitors. The input and output transformers would be on the PA board but the output filters could be a different board for ease of service.


I would also want the usual drain current monitoring along with input drive level, VSVWR protection, and logic that would shut down the amplifier in case it was operating in an unstable mode (oscillating).

Thermal monitoring would also need to include an air vane switch in case of fan failure or the amplifier is being operated at an altitude where the air is thin enough to seriously impair cooling. Most all of this stuff is inexpensive to add.



I'd love to see Freescale themselves tackle this and then come up with an app note showing all the details, like Motorola and others always did. There may be a reason their common app note is a VHF amp and not HF.

The thought has crossed my mind that these transistors may not be stable at lower frequencies. The datasheet makes me suspicious of that.

W8JI
10-12-2011, 11:10 PM
I found it in this article.

http://www.funkbox.ch/als-600.pdf

I'm not sure why that one is so low. Their other worse case reports at -35 dB or better.

Could have been a test error or bias issue. They typically test at -35 dB at 600 watts worse case.

AF6LJ
10-12-2011, 11:16 PM
Hi Rich,

Steve's suggestion is really about the best you can hope for, and the only one that makes any sense at all. Freescale can pay to have it done, or perhaps they can do it internally.

Sue, what's the rate around where you are for a RF engineer that can do that?

Here is mid-Georgia, it's about $100/hr.

73 Tom

I've been out of the loop since 94 I couldn't actually give you a reasonable estimate.
I've seen the amount of man hours that went into the design of a 40W S-Band PA back in the mid eighties and the costs were into the thousands of dollars for one prototype. That is in a well equipped lab and having all the material just a few doors away.

W6RZ
10-12-2011, 11:23 PM
I'm not sure why that one is so low. Their other worse case reports at -35 dB or better.

Could have been a test error or bias issue. They typically test at -35 dB at 600 watts worse case.
To be honest, that article just happened to be one of the first hits when I Googled "als-600 imd".

WB0LSR
10-12-2011, 11:28 PM
So, I am going to ask again:
Is there an electrical engineer out there that can design a circuit board for this kind of mosfet?if so, please contact me. This is for the goodwill of ham radio and to help other fellow ham radio operators in building a solid state HF amp.
Rich/W7EET
email:w7eet at arrl.net

While his amplifier doesn't use that specific FET, N8ZRY used an LDMOS gemini package as the final output stage of his ARRL homebrew challenge III entry. Really they're not a whole lot different from most other 50V FETs, so one could fairly easily start with a known design for an HF FET-based amplifier in the 300-500W range and incorporate elements of that design, scaling up as necessary. Biasing is very simple for FETs, and N8ZRY had posted some good info and tips for LDMOS stabilization in his ARRL thread here: http://forums.qrz.com/showthread.php?306287-100-watt-HF-power-amplifier-using-an-LDMOS-transistor-BLF647

and here: http://forums.qrz.com/showthread.php?314509-VSWR-protection-circuit-for-LDMOS-PA-transistors-update-from-the-6-amp-10m-homebrew-3

And a little SWR protection circuit he designed here: http://forums.qrz.com/showthread.php?314509-VSWR-protection-circuit-for-LDMOS-PA-transistors-update-from-the-6-amp-10m-homebrew-3

I have a few MRF6VP11KH parts on hand, which are the non-ruggedized version of the device you're interested in. Soon (if I can ever find the time) I will be building an amplifier with one of them.. shooting for 500W PEP. From what I've seen in designs and documentation, a copper heat-spreader between the transistor and the heatsink is sufficient for CW full-power usage, but most likely not at 100% duty. I've been seriously considering experimenting with TEC cooling, since I have a large quantity of them on hand and I'm very familiar with their drive circuitry. Since all that would be required is that a good difference be maintained between the hot and cold sides of the TEC, I think it can be done. These transistors can handle some heat, so they don't need to be cold or frozen.

WB2WIK
10-12-2011, 11:31 PM
To be honest, that article just happened to be one of the first hits when I Googled "als-600 imd".

I usually refer to the ARRL test reports for this stuff, as if they contain errors, the errors are likely to make the measurement "worse," rather than better; and they came up with 37 dB worst case.

I wouldn't want -30 dBc IMD products from a home station, either. For a mobile amp used mobile, it's probably okay.

The going rate here in CA for an RF engineer is probably more like $150/hour. But that engineer may not also do PC layout and optimization, since that's another specialty. We pay $200 an hour for that, but the guys are really good and run a lot of analytics on the layout before releasing it. Then, mirror-flat wet machining of copper and aluminum usually costs $60/hour for machine time, plus setup fixuring; so I couldn't possibly get that done around here for less than a couple of hundred dollars. There are hundreds of precision shops here doing aerospace work, and they're busy (thank God -- somebody's doing well in these economic times).

W6RZ
10-12-2011, 11:32 PM
I wouldn't use an amplifier only -30dB PEP at home on a big antenna, ever.
Just curious, but aren't many 13.8V transmitters in this same IMD range (or worse). I'm not sure what your primary rig is, but an FT-1000MP is in the -30 dB (and worse) ballpark.

http://ftp.qrz.ru/pub/hamradio/schemes/yaesu/FT-1000_ARRL_Test-result_report.pdf

WB2WIK
10-12-2011, 11:44 PM
From what I've seen in designs and documentation, a copper heat-spreader between the transistor and the heatsink is sufficient for CW full-power usage, but most likely not at 100% duty. I've been seriously considering experimenting with TEC cooling, since I have a large quantity of them on hand and I'm very familiar with their drive circuitry. Since all that would be required is that a good difference be maintained between the hot and cold sides of the TEC, I think it can be done. These transistors can handle some heat, so they don't need to be cold or frozen.

CW is probably about 50% D/C, higher than SSB but obviously a lot lower than RTTY, AM or FM. To make an amp "sellable" it might have to be marketed as SSB-CW only, or verified to work at 100% D/C, or be derated for full D/C operation as many are.

Hams are somewhat used to 8877 amps which can run 100% D/C at legal limit power with enough air, and will be operating well within their limits at that power. But SS amps are a bit different.

TEC cooling is interesting. We use ordinary water cooling of our CPUs in HPCs here, and that works darned well and should be a strong consideration for those who like efficient cooling systems that don't make a lot of noise.

Freescale says "Tj 150C" (although FETs have no junctions, but we know what they mean) and derates MTTF very quickly above that...down to about zero if you go much above that.

W6RZ
10-12-2011, 11:48 PM
I usually refer to the ARRL test reports for this stuff...
It's a link to the 2005 ARRL product review of the ALS-600S.

WB0LSR
10-12-2011, 11:50 PM
TECs can deep freeze, in fact some records have been set freezing CPUs with TECs and overclocking them. They are also silent.. Freezing something as hot-running as an RF power transistor isn't really practical, but keeping it WELL below 150C is I'm fairly certain. Never seen one used for this though... They really just move the heat away from the transistor into the heatsink, but using one could eliminate the need for copper or liquid cooling.

I'll be sharing anything I learn regarding the use of thermoelectrics in this application.. I'm actually pretty excited about the prospect personally.

WB2WIK
10-12-2011, 11:51 PM
Just curious, but aren't many 13.8V transmitters in this same IMD range (or worse). I'm not sure what your primary rig is, but an FT-1000MP is in the -30 dB (and worse) ballpark.

http://ftp.qrz.ru/pub/hamradio/schemes/yaesu/FT-1000_ARRL_Test-result_report.pdf

But you can run some of those rigs in Class A at reduced power and they clean up well. An FET amp won't require much drive. Even a bipolar exciter that doesn't measure very well at full power will usually measure better at reduced power.

WB2WIK
10-12-2011, 11:53 PM
TECs can deep freeze, in fact some records have been set freezing CPUs with TECs and overclocking them. They are also silent.. Freezing something as hot-running as an RF power transistor isn't really practical, but keeping it WELL below 150C is I'm fairly certain. Never seen one used for this though... They really just move the heat away from the transistor into the heatsink, but using one could eliminate the need for copper or liquid cooling.

I'll be sharing anything I learn regarding the use of thermoelectrics in this application.. I'm actually pretty excited about the prospect personally.

I've never seen them used in that application, either. I always thought of them as ways to keep food cold when travelling, and stuff like that. But seems like a good application...let us know what you find.

AF6LJ
10-12-2011, 11:59 PM
I've never seen them used in that application, either. I always thought of them as ways to keep food cold when travelling, and stuff like that. But seems like a good application...let us know what you find.

When I worked at Loral Corp there was a small in house project to use those for cooling transmitters for testing and alignment over temperature. Our existing method was to use liquified CO2. The heat pumps worked marginally wall for that application. The prototype plate that was built used six TC devices attached to an aluminum plate.

I can attest to how well they work for overclocking CPUs. :)

W7EET
10-13-2011, 02:06 AM
Those of the engineers that are on here let me know when you get a print of the pc board and what the matches are for the baluns and the biasing. I have a source for the filters already and for the split balun for the two modules for this mosfet. The power supply will not be a problem either. I am going to use 220 single phase to a 36 vac at 100 amp, into a full wave bridge using 100 amp diodes including filtering. The power supply is going to be separate from the amp. Building this thing is going to be a whole lot of fun. I also have test equipment to test the product for oscillations and distortion.
Rich/W7EET

WB2WIK
10-13-2011, 02:13 AM
Those of the engineers that are on here let me know when you get a print of the pc board and what the matches are for the baluns and the biasing. I have a source for the filters already and for the split balun for the two modules for this mosfet. The power supply will not be a problem either. I am going to use 220 single phase to a 36 vac at 100 amp, into a full wave bridge using 100 amp diodes including filtering. The power supply is going to be separate from the amp. Building this thing is going to be a whole lot of fun. I also have test equipment to test the product for oscillations and distortion.
Rich/W7EET

Rich, I suspect "nobody" is going to undertake this unless it's a pure labor of love. Maybe someone retired with a lot of time on his hands. I'd think the best bet is to push Freescale to do this work and publish the circuit, the board layout (preferably complete Gerbers) and parts list. This is probably 40-80 hours of work, full time, and I can't envision anyone doing it unless they were dedicated to some goal.

Freescale should be most motivated, as such a design could boost sales of the devices. That's why Motorola always did this stuff (and so did Thompson-SGS and many others).

WB2WIK
10-13-2011, 02:20 AM
When I worked at Loral Corp there was a small in house project to use those for cooling transmitters for testing and alignment over temperature. Our existing method was to use liquified CO2. The heat pumps worked marginally wall for that application. The prototype plate that was built used six TC devices attached to an aluminum plate.

I can attest to how well they work for overclocking CPUs. :)

We never overclock CPUs, but we do water cool them to keep them running. We water cool the Xscale processors on RAID controllers, also, simply to keep then running on sound stages in uncontrolled environments. Without that, they go offline and production stops, since no amount of air can keep them going.

W8JI
10-13-2011, 02:24 AM
Rich, I suspect "nobody" is going to undertake this unless it's a pure labor of love. Maybe someone retired with a lot of time on his hands. I'd think the best bet is to push Freescale to do this work and publish the circuit, the board layout (preferably complete Gerbers) and parts list. This is probably 40-80 hours of work, full time, and I can't envision anyone doing it unless they were dedicated to some goal.

Freescale should be most motivated, as such a design could boost sales of the devices. That's why Motorola always did this stuff (and so did Thompson-SGS and many others).

Actually Motorola and others did the boards because they had to have them anyway to prove the device worked and was stable, and to get IM tests. Without the broads, they could never have really known the devices would be OK in a system. The resonant single-device test setups won't fly for wide band or push pull applications.

The Motorola boards were never intended for mass production. They were starting points that took over where the factory left off. Some of them are not actually safe for the device. For example the one for 4x MRF150 has a "strip line" resonance at the third harmonic that puts 20-30 extra volts on the drains of the FET's on some frequencies. This can pop FET's.

If Freescale wants to market the device, they will build a basic starting board for HF.

WB2WIK
10-13-2011, 02:29 AM
Actually Motorola and others did the boards because they had to have them anyway to prove the device worked and was stable, and to get IM tests. Without the broads, they could never have really known the devices would be OK in a system. The resonant single-device test setups won't fly for wide band or push pull applications.

The Motorola boards were never intended for mass production. They were starting points that took over where the factory left off. Some of them are not actually safe for the device. For example the one for 4x MRF150 has a "strip line" resonance at the third harmonic that puts 20-30 extra volts on the drains of the FET's on some frequencies. This can pop FET's.

If Freescale wants to market the device, they will build a basic starting board for HF.

Good info. Did CCI modify the original designs or do you think they're marginal? I've built a few of the CCI kits and they worked okay, but I had to add filter boards after them. I used a simple Drake TV-1000-LP on one of them since I only used it on 10m when I had it in the trunk and my "rig" was an HTX-100 which was only a 10m rig. I modified the CCI RF COR circuit a lot because it wasn't reliable, but the amp itself was; I still have it!:o

W8JI
10-13-2011, 04:48 AM
I'm not sure. As far as I know, they never changed them. They were all done by Helge Granberg back when the USA had Motorola making good parts.

W9GB
10-13-2011, 01:26 PM
Did CCI modify the original designs or do you think they're marginal?
I've built a few of the CCI kits and they worked okay, but I had to add filter boards after them.

The only time that I have seen a modification was for part availability, such as the voltage regulator.

Helge used the circular metal can version, LM723H; Instead of the DIP version, LM723J.
http://www.national.com/ds/LM/LM723.pdf

That was a common usage in late 1960s and early 1970s. Many Popular Electronics, Electronics Illustrated, and Radio-Electronics magazine authors
used the metal can versions of ICs in their construction articles. They did look more like the discrete transistors of the 1960s.

The low pass filtering is mentioned in Helge's Applicaiton Notes -- BUT no specific design was included in the
Applicaiton Note -- SO in the 1970s many of the illegal CB amplifier builder just built what was shown.

Some poor soul even used the Motorola trademark (which was on PC board artwork in first Application Notes) on the PC boards they made for illegal CB amplifiers.
They found him --- and he paid dearly for that mistake.
Motorola eventually edited the Application Notes to remove their name and trademark from the PC board artwork.

w9gb

W7EET
10-13-2011, 03:07 PM
When I construct this amp; my plans is to leave the 10 meter design out of this amplifier. I am like everyone else with the fear of some CB'er finding it's way of it's construction amp on their table to use on 11 meters. I would like the FCC move 11 meters to the 4 or 5 meter band with it's 40 channels and give back our 11 meters.
Rich/W7EET

WB2WIK
10-13-2011, 03:16 PM
When I construct this amp; my plans is to leave the 10 meter design out of this amplifier. I am like everyone else with the fear of some CB'er finding it's way of it's construction amp on their table to use on 11 meters. I would like the FCC move 11 meters to the 4 or 5 meter band with it's 40 channels and give back our 11 meters.
Rich/W7EET

Nice wish, I can't see how it could happen. VHF (30-300 MHz) is fully allocated, even with many TV stations relocating after the digital transition. I think CB should be moved up to the 13cm band so enthusiasts can start messing with microwave ovens to run more power.;)

That won't happen, either.:o

WB0LSR
10-13-2011, 06:22 PM
When I construct this amp; my plans is to leave the 10 meter design out of this amplifier. I am like everyone else with the fear of some CB'er finding it's way of it's construction amp on their table to use on 11 meters. I would like the FCC move 11 meters to the 4 or 5 meter band with it's 40 channels and give back our 11 meters.
Rich/W7EET

All legality aside, personally I think that if CB amp builders would include the necessary items to keep their signal clean and avoid overdriving the active elements there wouldn't be much of a problem if they do run power. But they don't.. HOWEVER IMO as more and more information about how to properly build an amplifier is found online and elsewhere, future amp builders might be exposed to it and learn something.. keeping them ignorant is the main reason for crappy splatterboxes in the first place.

I know, I know, the #######s should just NOT run power.. even better solution right? WRONG. Why? Because it's unrealistic. They are GOING to run power whether we or the gov't want them to or not. Flooding the web and any other resource possible with the CORRECT information is far more beneficial.

W8JI
10-13-2011, 11:19 PM
I always felt CB operators should be allowed to run any amount of power they like with only two restrictions backed by civil penalties:


1.) All emissions outside the CB channels should be in ambient noise at one mile.

2.) All RFI problems locally are 100% their responsibility.

That would solve all problems.

The real thing that went wrong with the FCC started in 1984. Our leaders started thinking government was the root of all evil, big money was good, and started taking the FCC apart and turning it over to political appointees and lawyers.

K7MH
10-15-2011, 05:27 PM
CB operators

Hmmm...
It started out as a pretty interesting thread.

Looks like it is done for!!

W7EET
10-15-2011, 09:30 PM
No not really it just got side tracked. I am still looking for Electrical engineers to design a pc board for HR amplifier with the mosfet or the new mosfet that is out on the market.
Rich/W7EET

WB2WIK
10-15-2011, 11:45 PM
No not really it just got side tracked. I am still looking for Electrical engineers to design a pc board for HR amplifier with the mosfet or the new mosfet that is out on the market.
Rich/W7EET

Do you have a budget for this or were you hoping someone would just do it for the sake of science?

If the latter, I'm guessing that may eventually happen, but I don't know by whom. Did you contact Freescale to see if they have an HF test circuit on their roadmap? I'd hope, if the device is worthy of HF operation, they'd undertake this themselves as a marketing development tool.

W7EET
10-16-2011, 12:00 AM
What I was hoping for is to find a engineer to design a PC board and tell me the parameters of what is suppose to be on the PC board. So, I could put it together and buy the parts to make it work. Your second question about Freescale; No I have not contacted them. I did try once but they did not reply to me.
Rich/W7EET

WB2WIK
10-16-2011, 09:24 PM
To me, the "problem" is that the best engineer in the world can't verify a design without building it and making measurements. Thus, a "PC board design" has little merit until it's built, tested, de-bugged and likely re-designed. That's just the way things are.

I've designed and laid out hundred of PC boards for various things, but the "real" working models are always second or third generation, not first. That's why we only make 5 of the first version, since it's never the final version unless it's something very simple. So, to do this, the engineer would need to have the Freescale FETs along with other parts, lay it out, optimize it using a CAD program (easy), have it fabricated, build the design, test it, and then (usually) go back to the drawing board to make changes.

A VHF or UHF amp is actually easier in almost all respects, to me, since the operating bandwidth can be quite narrow. An HF amp is a bigger challenge, as we're covering at least 3 octaves and maybe four. So the input/output transformers need to be very good, and all decoupling circuits might have to work from 1.8 through 29.7 MHz, which is not so easy.

Unless a ham does this just to do it (which evidently nobody has, yet), I'd rely on Freescale to do it.

W8JI
10-17-2011, 02:53 PM
I contacted FreeScale months ago and asked for any data on those FET's. I would do a design that would sell thousands of FET's a year if it was the correct FET for the job.

They never responded.

Then I asked for an applications engineer to contact or call me about HF linear applications. Nothing happened.

IMO if they don't respond to a potential or likely market of thousands of devices, they probably do not have a response.

Another rule for production is there always must be a second independent source for a substitute component, or a way to work in a replacement. Otherwise customers can be stuck with an obsolete product, and all the investment in the design is lost.

To do a proper RF module, fully tested and proven to be repeatable, takes a few passes. Each pass has to be one or more prototypes (some fail at one and need a redesign). The less time is spent picking through every single detail, of which there are several complex areas, the less likely a layout will work on just two passes.

As Steve correctly points out, a single band or frequency system is much easier than a 1 through 30 MHz system. With the demand for good RF engineers giving almost unlimited paid work, it is unlikely to find someone that will gift $25-50K worth of work for "spirit" for someone else to give away. :-)

The only option is almost certainly Freescale deciding to fund a public board.

73 Tom

W7EET
10-17-2011, 04:15 PM
My trade is a electronic technician in the RF field. I wanted to make something for other hams to have fun in making a kit by scratch. Today hams has lost the idea of kit building, by going down to the local store and by the product from the shelf. I really enjoy putting something together and making it work. For an example, The heath kit SB 104 had several problems with it one was the solid state driver. It had lot of distortion in the RF it produce. I did some experimenting and got the problem solved. After that it was a great transceiver. I got in touch with Freescale today by email. They told me that they have a pc for 160 meters thru 10 but not for 6 meters with the new transistor but I will see if they come up with something. I will let everyone know if they do or not within the next couple of days.
Rich/W7EET

WB2WIK
10-17-2011, 05:04 PM
That's actually really good news (that they have a 160-10m board layout, which hopefully has been built, tested and verified). I hope they also have a good parts list and transformer details to go with that.

I wouldn't sweat the 6m stuff.

W6RZ
10-18-2011, 08:29 AM
HF/6M amplifier using the MRFE6VP61K25H.

http://www.nikkemedia.fi/juma-pa1000/

WB2WIK
10-18-2011, 03:13 PM
HF/6M amplifier using the MRFE6VP61K25H.

http://www.nikkemedia.fi/juma-pa1000/

Anyone know if they actually produced the kit? The page says, "Our intention is to make a kit..." but doesn't really state if they did it.

W7EET
10-18-2011, 04:44 PM
OK everyone: Here is the scoop from Freescale. They do not have a pc board as of yet but; They may or might produce a test amplifier for HF and sell the boards. I told them that there will be other ham radio operator that will be interested in building a home brew amplifier with this new mosfet. I also told them I was interested in two boards for my home brew amplifier. It probably will help if any of you folks are interested contact Freescale and let them know.
Rich/W7EET

AF6LJ
10-18-2011, 05:10 PM
Anyone know if they actually produced the kit? The page says, "Our intention is to make a kit..." but doesn't really state if they did it.
That's really nice looking.
That would be a nice addition to my shack. :)

W7EET
10-18-2011, 05:26 PM
Thank you WB2WIK,
That is a really nice HF-6 meter amplifier with the new mosfet. I have already emailed them! We will see how much the amp is in the very near future. It is very well engineered in it's design and they did very good job.
Rich/W7EET

WB2WIK
10-18-2011, 05:50 PM
Thank you WB2WIK,
That is a really nice HF-6 meter amplifier with the new mosfet. I have already emailed them! We will see how much the amp is in the very near future. It is very well engineered in it's design and they did very good job.
Rich/W7EET

I didn't see more than the pics on line. Is there more to look at?:o

I couldn't see the heat sink at all, since it seems to be in a box with a fan at the end of it. I'm kind of surprised they could get away with only one fan, but maybe the 1 kW rating is PEP for SSB only, which is low duty cycle...couldn't really tell what its key-down (or RTTY) rating was. Pretty packaging job, though!

W7EET
10-18-2011, 10:46 PM
There is two fans on the heat sink, one at each end. The pic's are a little deceiving. The box is the heat sink and the amp weights 30 lbs. I can also see the filters for the amp. I emailed Finland to find out the price of the amp.
Rich/W7EET

AF6LJ
10-18-2011, 10:49 PM
Let us know what you find out.
:)

W7EET
10-19-2011, 07:57 PM
sorry folks, but I had to email them again today. On my first email there was no reply. I did find another email address so I am trying that one. There is a great interest in this amp, not only on here on the form but also in other areas. Let's wait for 24 to 48 hours and see if I can get a response from them.
Rich/W7EET

W7EET
10-21-2011, 03:41 PM
This is friday oct 21 and still no reply from Juma amplifier by email. I have sent two emails so far.
Rich/W7EET

W7EET
10-21-2011, 03:41 PM
This is friday oct 21 and still no reply from Juma amplifier by email. I have sent two emails so far.
Rich/W7EET

W9GB
10-21-2011, 06:17 PM
I went to the Juma web iste:
http://www.nikkemedia.fi/juma/

It plainly states that Partco Oy will be handling the ordering and shipping of Juma kits directly to the customers world wide.
The managing director of Partco Oy, Mr. Pentti Honkanen, OH2AVL who coordianted/negotiated this logistics and distribution deal.

I would contact Mr. Honkanen at Partco Oy in Helsinki, Finland
http://www.partco.fi/

Partco Oy
PL 45
Teuvo Pakkalan Tie 9
FI-00400 Helsinki
Finland
Telephone: +358 (0)9-587 6960
Fax: +358 (0)9-587 6990

W7EET
10-25-2011, 12:36 AM
Today monday 24 oct 2011:
I got a reply from Juma. They said, momentarily at this time there is a stand still until later for the amp kit. They did not give me any price but they referred me to email someone else for further details what is going on with the company.
Rich/W7EET

WB2WIK
10-25-2011, 12:59 AM
Sounds like it's a one-off prototype and not a released product.

The difference is tremendous, in terms of the work required.

W6RZ
10-25-2011, 10:18 AM
Just to get a feel for a possible price, here's a link to a 2-meter amplifier using the MRFE6VP61K25H.

http://www.beko-elektronik.de/index.php?do=hlv1000

2370 Euro = 3300 US dollars.

WB2WIK
10-25-2011, 03:06 PM
Just to get a feel for a possible price, here's a link to a 2-meter amplifier using the MRFE6VP61K25H.

http://www.beko-elektronik.de/index.php?do=hlv1000

2370 Euro = 3300 US dollars.

Zowie.;)

To make this long enough, Zowie again.

W7EET
10-26-2011, 03:41 PM
Thank you very much for the link for the 2 meter amplifier.
I am still waiting for the other email from juma.
Rich/W7EET

W8JI
10-26-2011, 04:01 PM
Zowie.;)

To make this long enough, Zowie again.

So they say 1 dB compression point is 950 watts, but no mention of IM3 or IM5 tests. Probably a 700-800 watt PEP amp at acceptable IM3.

W7EET
11-02-2011, 06:02 PM
I never heard from Juma. I do not know what is going on there at the company. Maybe they are having economics problems call money. I did contact beko on their 2 meter amp and they also have a 6 meter amp with that same mosfet transistor. The us dollars is 2900 bucks not 3300. There is a shipping cost of 200 bucks. That looks like a really nice amp for 2 meter SSB and CW. If I had one of those amps I would certainly want to not use it only on a occasion or not all the time due to the repeaters just above in the145 range. I am sure there will be some intermod.
Rich/W7EET

W7EET
11-17-2011, 02:23 AM
Here is the up grade information about Juma as of today. They have replied to me by email. The reason why it took so long because they were swamped with email for information on the amplifier. Here is a copy of that email Thank you everyone for your support
Rich/W7EET

Hello all,



Thank you for your interest in JUMA PA1000 linear amplifier. We have got lot of emails concerning the availability, price and other issues.



We published the JUMA PA1000 preliminary information www.nikkemedia.fi/juma-pa1000 in a very early stage because there are very limited HF application information available for the new Freescale MOSFET.



Currently we have two working prototypes. The MOSFET and main functions are performing very well and we will continue testing. We are not yet fully satisfied with some functions and we need to improve some circuits e.g to reach the targeted broad band performance. Additionally there are some concept issues, like more sophisticated user interface, auto band selection, lighter power supply etc.



Unfortunately we are unable to give any price information or schedule yet. It will take some time to get ready with all the tasks.



Please follow Juma Forum board.jumaradio.com We have opened a new topic there for JUMA PA1000 information and conversation.



73 Juha OH2NLT and Matti OH7SV

WB2WIK
11-17-2011, 02:35 AM
Here is the up grade information about Juma as of today. They have replied to me by email. The reason why it took so long because they were swamped with email for information on the amplifier. Here is a copy of that email Thank you everyone for your support
Rich/W7EET

Hello all,



Thank you for your interest in JUMA PA1000 linear amplifier. We have got lot of emails concerning the availability, price and other issues.



We published the JUMA PA1000 preliminary information www.nikkemedia.fi/juma-pa1000 in a very early stage because there are very limited HF application information available for the new Freescale MOSFET.



Currently we have two working prototypes. The MOSFET and main functions are performing very well and we will continue testing. We are not yet fully satisfied with some functions and we need to improve some circuits e.g to reach the targeted broad band performance. Additionally there are some concept issues, like more sophisticated user interface, auto band selection, lighter power supply etc.



Unfortunately we are unable to give any price information or schedule yet. It will take some time to get ready with all the tasks.



Please follow Juma Forum board.jumaradio.com We have opened a new topic there for JUMA PA1000 information and conversation.



73 Juha OH2NLT and Matti OH7SV

Sounds to me it's not ready for prime time. It will be interesting to discover what they find out as they continue testing.

Thanks for the update.

VK4KGW
11-17-2011, 06:42 AM
I never heard from Juma. I do not know what is going on there at the company. Maybe they are having economics problems call money. I did contact beko on their 2 meter amp and they also have a 6 meter amp with that same mosfet transistor. The us dollars is 2900 bucks not 3300. There is a shipping cost of 200 bucks. That looks like a really nice amp for 2 meter SSB and CW. If I had one of those amps I would certainly want to not use it only on a occasion or not all the time due to the repeaters just above in the145 range. I am sure there will be some intermod.
Rich/W7EETWell after making enquireis a month ago this arrived via email today

""Hello all,



Thank you for your interest in JUMA PA1000 linear amplifier. We have got lot of emails concerning the availability, price and other issues.



We published the JUMA PA1000 preliminary information www.nikkemedia.fi/juma-pa1000 in a very early stage because there are very limited HF application information available for the new Freescale MOSFET.



Currently we have two working prototypes. The MOSFET and main functions are performing very well and we will continue testing. We are not yet fully satisfied with some functions and we need to improve some circuits e.g to reach the targeted broad band performance. Additionally there are some concept issues, like more sophisticated user interface, auto band selection, lighter power supply etc.



Unfortunately we are unable to give any price information or schedule yet. It will take some time to get ready with all the tasks.



Please follow Juma Forum board.jumaradio.com We have opened a new topic there for JUMA PA1000 information and conversation.



73 Juha OH2NLT and Matti OH7SV





-- All the recipients are intentionally as "Bcc" in the mailing list --""

W7EET
11-17-2011, 05:51 PM
I was not impressed or over thrilled of the email response time either. It will be interesting to find out the kit price and shipping. I hope they get everything ironed out with the minor problems of their design.
Rich/W7EET

VK4KGW
11-18-2011, 03:54 AM
I was not impressed or over thrilled of the email response time either. It will be interesting to find out the kit price and shipping. I hope they get everything ironed out with the minor problems of their design.
Rich/W7EEThere is a 4z4 using the chips I think and making some serious claims about ithem ( or might be similar not sure) , he is an engineer and I have used his designs with success but can't comment on his current developments , and yes ebay might bring a lead

W4QBQ
11-20-2011, 03:29 AM
Some few nights ago I was listening in on a QSO between a few Hams about Amps., there was one in particular that was holding my attention as he seemed very knowledgeable on the topic. This particular individual said he was a radio/tv broadcast engineer in the Maryland area. I thought I copied his call, but when looking it up the next day there was no such thing. He was extolling the virtues of Transistor over Tubes and how virtually all commercial stations now use Transistors or are changing to them. He also was telling of the Freescale Transistor being discussed in this thread including that he thought it was cheap and superior in function over others. He went on to say that he had built a "Backpack Amplifier" using that Transistor and had also taken it to the Dayton Hamfest and shown/demonstrated it to people at Alpha and had it tested by them, with what he thought were satisfactory results.
I was disappointed I didn't get his call as what he had done sounded appealing to me. I looked up the product http://www.mouser.com/Semiconductors/Discrete-Semiconductors/_/N-6hpe7Zlls6?Keyword=191848785&FS=True
and the You Tube video he mentioned and then came to QRZ to see what's up and I found this thread.
In the 50s and 60s there were home brew designs for Linear Amps. in the ARRL Hand Book, it would be nice to see something like this in there in the future.

JIM

KB9QKR
11-22-2011, 09:38 PM
This might be who you are talking about, "KC3VO's 2kW ham radio backpack amplifier"

http://youtu.be/Nxp_Nsa54_Q

W4QBQ
11-23-2011, 03:31 AM
Yup, sounds just like him and I had written KC3VL for the call, miss heard the O as L.
Now you have it. Get him to draw it up and go for it.

JIM

KB9QKR
11-23-2011, 09:22 PM
I have been following this MOSFET VERY closely and been doing hours of research. (borderline obsessive);)
This started when I found we had been throwing away 50VDC 120Amp switching power supplies out of telecom and server gear for the price of scrap!

I am no RF engineer, but probably know just enough to be dangerous so I have been looking for a reference circuit that would steer me in the right direction.

My brainstorming (as it stands this hour) has lent me to use this test-circuit/board that uses a MRF6VP11KH and install the MRFE6VP61K25H in its place (as they seem to use the same case), and tweak supporting components where needed like using RF transformers from Communication-Concepts.

http://www.freescale.com/files/rf_if/doc/data_sheet/MRF6VP11KH.pdf


This is really just something I have been researching purely for fun. Ham radio has always been trial and error, and I for one love this hobby because of things like this!

BTW, a month or so back I finished modifying a power supply out of an IBM blade server that now supplies me with 12V DC at 230AMPS! (once again, trial & error)

W8JI
11-24-2011, 09:41 PM
From the data it looks like that FET might be pretty clean up to 600-800 watts, if you can get the heat out of it.

G0HZU
12-02-2011, 08:30 PM
Are there any decent non linear models available for the part?

You should be able to have a play using a decent RF design package like Microwave Office and you could learn a lot from a computer simulation. eg P1dB, Psat, efficiency and IMD/harmonic performance. 1kW power levels are a bit scary (400W limit here in the UK) but I guess if the model for the device is decent then it would be worth a play on a computer. You can also do the thermal modelling on a computer although at these power levels you can't afford to make any errors in your modelling!

G0HZU
12-02-2011, 08:58 PM
I just had a quick look to see if there were any non linear models for it but couldn't find any. If you could get these from Freescale you could characterise a design quite well for P1dB and efficiency assuming their models are good.

For example, companies like CREE release extremely good non linear models of their devices allowing remarkably accurate simulations. But these are for lower powered devices across 10W to 100W for example. I don't know about getting good non linear models of large devices operating at 1kW power levels though...

G0HZU
12-03-2011, 02:12 AM
I've skimmed through this whole thread and I think a few of you are prejudging the capabilities of this device based purely on the application circuit in the datasheet (the pulsed amplifier?).

This is a bit naive if you don't mind me saying and you really need to deal with Freescale directly (i.e. get through to an engineer via a sales rep) and find out what it can deliver with different transformer/balun topologies. Also, some of the spinoff designs linked to in this thread look a bit 'optimistic' based on what I see on their PCB in terms of the choice of output transformer ratio etc.


It's a very interesting device though :)

G0HZU
12-03-2011, 05:04 PM
One thing you can ALL contribute to is towards one of the first essential steps in a design.

After an initial 'business case' to justify the need for such an amplifier (I assume this has been done already :) ) you can then contribute to and/or peer review a set of requirements for the amplifier.
A requirements document can typically be as simple as text entries in an excel spreadsheet with lists of design requirements and comments in each column.

Eg for temperature range you can list columns for max and minimum temperature and include column entries for 'mandatory' and 'desirable' in terms of temperature.
You will be surprised how quickly the document can grow if several people contribute and it becomes the reference for the design so the more entries the better. Other entries can be the obvious ones for size/power/weight/cost/etc etc

Adding columns for desirable and mandatory can help the designer strike up a compromise in key areas. Don't overspec it or you can end up with showstopper reports from the designer.

i.e. without a formal requirements doc you can't really approach a design house and expect them to fill in the blanks (unless they are already on your team)
Basically it isn't fair on the RF engineer if he/she is expected to keep asking you for this info and if you are paying by the hour then you can waste lots of cash very quickly... :)

G0HZU
12-08-2011, 04:43 PM
I contacted Freescale at work today and there are non linear models available for this device :)
I'm registered with them via my place of work and I've now got hold of their non linear models for this device that have been developed for Microwave Office. They also do models for ADS.

I've not had a chance to install the libraries or the associated model kit into MWO yet though. It does look a bit fiddly to do.
But basically anyone with access to MWO should be able to play on a simulator and tinker with RF and thermal modelling of this device. I've designed broadband amplifiers across several GHz with MWO and the simulation results are usually excellent providing the models are good and you know how to model the PCB and components adequately.

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