Just say NO! to Winlink expansion!

ae1x:
"Your problem is that you are missing part of the reason for this service. Learning about radio has to being somewhere. Just where do you think the learning process is suppose to begin, in the classroom?

Amateur radio is and has been a place to begin experimenting with RF electronics to learn how to do things. It is not just the venue for the experienced and wealthy. It is a place for anyone with an interest in any form of radio signaling to actively attempt to communicate for whatever reason he/she wishes to communicate. You represent only one form of communications and you want to dominate all the spectrum allocated for all the interests that exist in this service.

Look, the issue should not be the efficiency of what we do. There must be space for all interests, not just digital interests."

Ken,

Once again, you've pretty much hit the nail on the head.

My son learned about transistor biasing, impedance matching, and balanced modulators in building the DSB transmitter.

Whether Larry wants to admit it or not, these are standard techniques that need to be understood by anyone in electronics. Whether the transistor is on a piece of circuit board or is located on an integrated circuit substrate, biasing techniques still apply. So do all the other techniques, be they implemented in discrete components in and IC or in software.

Forcing people to bypass the simple stuff means they have no knowledge of the underpinnings of the art.

It's too bad that a few elitists in our hobby feel that "Let'em eat cake" is the right attitude to have toward the newcomers to the art of radio.

tim ab0wr

 

Tim,

Since Larry has indicated that he is not a WL2k proponent, but rather a proponent of advancing the radio arts. It appears that a technical discussion is not productive. He believes his mathematical skills are far superior to yours.

Larry,

It was not Tim that made what you call an inflammatory comment it was I and I stand by it. If the shoe does not fit your foot, I'm sorry, but it does fit many of those yahtsmen that rely on this for a multitude of things including navigation, safety, and other reports. Many of these people are elitists and have demonstrated this behavior in other posts.

I will state again, there must be a place for the new entrants to perform experiments to develop his/her own skills and this usually includes CW, AM, DSB, SSB, and etc. Amateur radio is not simply a place for advanced communicators with leading edge technology. There should and must be space for all of these interests!

What about antenna experimenters? They ususally use just single frequencies. Modulation is not required for testing until real communications are attempted.

What about QRP operations? We usually use simple equipment. This is my interest and it should be protected. There are those who use QRP SSB or DSB. These users should be protected as well.

Your comments would seem to preclude both of these examples because they are dealing with 50+ year old technology. I submit that they must be accomodated as well as the digital operators!

Ken

 

I think what we have seen here is a special interest agenda that was pushed through the system. I believe there was hope that it would slide through without anyone even noticing the ramifications of such a plan. The ARRL membership represents less than 20% of the amateur population. I'd be willing to bet that even that 20% does not, or will not support this plan. The majority of AR operators have no idea what has transpired as yet, but day by day there is more talk about this on the bands.

Thanks to people like K6hty, ad4mg, n5pvl, and a host of others our awareness of this potential nightmare has increased. The anti-special interest forces will continue to gather momentum as the days and weeks move forward. This bandplan has the potential to cause what in essense would normally be considered "malicious interference", by automatic and semi-automatic machines. It cannot be allowed "as is".

 

It would be nice if the one who claims to be "the teacher" understood his subject. MCW is NOT the same as "CW" - regardless of the similarities. For one thing, the output is at carrier + 1000 Hz (USB) or carrier - 1000 Hz (LSB).

The 1000 Hz tone is simply AUDIO modulating a carrier via a balanced modulator. The result is translated to the output frequency. If the tone is 2000 Hz, same result - different offset.

Because the receiver "supplies" the missing carrier, and because the carrier to received signal tone may be varied, the reception is "like" CW - but it IS NOT CW.

For true CW, my offset from the carrier equals my receive tone. If I desire a 500 Hz tone, I will tune +/- 500 Hz from the carrier for the CW signal.

For the MCW case, my offset from the 1000 Hz tone equals my receive tone. To get a 500 Hz tone from the 1000 Hz MCW signal in USB mode, I must tune 500 Hz ABOVE the carrier (=500 Hz BELOW the tone), or 500 Hz ABOVE the tone.

Apples are not oranges - and MCW is not CW. Pure and simple.

 

The ONLY "special interests" in this discussion are those who seem bent upon dragging ham radio into the past - and preventing it from having a future.

The bands would REMAIN available to ALL modes. The only limit would be bandwidth.

If some want to run modes that inhibit - rather than advance - communications effectiveness (e.g., AM, DSB), perhaps a set of "wideband" frequencies could be set aside for that. As far as I am aware, NO ONE HAS PROPOSED THAT IN ANY FORUM.

The absolute GARBAGE being put forth by those who want NO advancement has been PROVEN false many, many times. The replies are usually of the form "well, he didn't answer this" - even when the issue has been REPEATEDLY answered. Then the "cover" shifts to " but he REALLY said (pick anything 180 degrees from the ACTUAL).

When all else fails, the chorus becomes "It's those 'elitist" Winlink guys taking OUR bands!" This, in SPITE of the FACT that Winlink operation are VERY limited on HF - and that what is REALLY being discussed are modes that include voice AND data.

It is NOT about a single service/group/technology. It is about REMOVING BARRIERS that PREVENT the use of modern modes and technologies. And it is ULTIMATELY about opening the way for the experimentation that wil produce some amazing results.

Please stop the false and harmful statements, and lets start to figure out how to work toward a sane plan.

SSB will be around for a LONG time - but it WILL be replaced by a better mode. The question is: Will ham radio exist to see it?

 

Let's see a 10 Watt exciter for $25.00 from all new parts for the DSB mode. Just in case you can manage that (and I doubt that you can build a 10 Watt DSB transmitter for $25.00 - in any technology), why not add about $5.00 to $10.00 and make an SSB exciter with xtal filters?

Of course, for practically ZERO extra, you can build a phasing SSB exciter. Just a few more parts than a DSB - and TWICE the effective power for the same output Watts.

In the much more realistic $50.00 to $150.00 range, there are several DSP options - including special learning systems. THAT is the direction that I would point a kid. Build the RF amplifier, the receiver front end, and the mixer - then let the DSP be the exciter and the receiver. LOTS of "bang for the buck" --- and TOTALLY reconfigurable.

When the kid gets into more money, he/she can change to a faster DSP chip and work at a higher IF - or build a fully DSP receiver / exciter. In any case, he/she can have a very capable RX/TX for a shoestring budget - and one HECK of a selling point on his/her resume and/or college application!

Building a DSB exciter just WON'T get much notice on either a resume or a college application! We may not like it, but that is simple reality.

 

What questions? Your "Well, he got me on that one, so I need to change the subject" nonsense?

The world does not revolve on formulae. My "Electronic Engineers' Handbook" has all of the ones I need - as does my copy of MathCAD. Just as all other engineers, I check my formulae against the source - and then PROVE the results.

I have some very nice sheets set up in MathCAD to run simulations.

 

I see, if we allow EMAIL for yachtsmen and rv owners  to take our bands that is considered progress?  That is the advancement of radio?

Yep, man vs. machine.  Gee, I wonder who will win that battle?

That is quite simple. Automatic and semi-automatic modes need to be in their own sub bands, or by gentlemen's agreement.  They should not have full reign with phone.

No, ham radio will not exist if we allow a plan that allows email to cover our phone bands.

 

wa5ben:
"Please stop the false and harmful statements, and lets start to figure out how to work toward a sane plan."

You mean like your claim that a DSP or DDS based homebrew transmitter would be cheaper than a simple DSB transmitter?

I'm still waiting for the parts list including part costs and circuit board costs for this DSP/DDS transmitter. Remember, your goal is $25.

tim ab0wr

 

Larry,

You're full of bull. You can not distinquish an MCW signal from a CW sign nor can you distinquish between an FSK and an AFSK generated by a SSB tranceiver unless you are using a spectrum analyzer and looking for the suppressed carrier and image sideband. Get real!

I'll say it again, building minimal equipment and experimenting with antennae are both parts of amateur radio. Amateur radio is not only about advancement of the radio arts. What you have indicated is an elitist attitude. Amateur radio is about learning about electronics, propagation, networking, EMCOMM, and etc. There must be a place for all of the above.

The advantage to the proposal on the table is precisely what is needed, but we must be assured that one small group of elite users does not dominate our spectrum and run all the other people off of the bands. That is what I'm against! We also must be sure that we have sufficient technical justification for the bandwidth numbers that we use for the segmentation.

What would you have us do, teach electronics on the black board only? Electronics is best learned by a combination of theory and practice. This is how electronics has been taught and continues to be taught. One has to learn the basics first and progress to more advanced stuff.

Do I think DSP is a good thing? You bet! It's another tool in our bag of tricks that can and will be exploited to advance our art, but it is not the only tool. One still has to develop amplifiers, oscillators, filters etc. not just DSP filters, but discrete filters as well. They will always have a place in this world. Our spectrum is still one of the best laboratories for teaching RF electronics. Ir gives everyone somewhere to learn to use the basics. I'm sorry if you do not want beginners to share spectrum with you advanced users. I guess you think you and your ilk are the only ones that should have licenses to operate an amateur station.

Look, I've been in electronics since my sophmore year in high school. That was in the fall of 1967. I've watched the transistion from tubes to transistors, from transistors to ICs, from discrete logic to programmable logic, and then on to microcontrollers. DSP is here too and will find its place on our bands. I started in amateur radio in 1972 as a technician and watched a lot of things happen in radio. I went to work for M.I.T. Lincoln Laboratory in 1972 and had a hand in development of a wide array of technologies that are now the state of the art in commerical communications. Please stop preaching about advancing the radio arts and leaving out all the other wonderful things that amateur radio represents.

The real question raised by this forum is whether we should just SAY NO to the ARRL/WL2k proposal that's on the table or should we attempt to make it work by debating how this can be brought about. This forum has brought out many important questions that need answers during the debate. Your statements and arguments have merit, but are not the entire picture. You are advocating from a narrow point of view when the real issue here is the big picture.

Ken

 

wa5ben:
"Let's see a 10 Watt exciter for $25.00 from all new parts for the DSB mode. Just in case you can manage that (and I doubt that you can build a 10 Watt DSB transmitter for $25.00 - in any technology)"

Larry, I said a 1/2 watt transmitter, not a 10watt transmitter. And we did manage that. Here's a parts list:

3 - 2n2222a transistors ($0.15)
1 - mpf102 fet ($0.16)
4 - 1n914 diodes ($0.16)
4 - t50-6 toroids ($1.20)
1 - 2n5109 transistor ($1.50)
1 - 9.046 Mhz crystal ($0.50)
miscellaneous disc capacitors ($1.50)
miscellaneous resistors ($1.50)
1 - 6" x 6" piece of double sided circuit board ($2.25)
1 - old radio shack dynamic microphone ($2.00)
miscellaneous magnet wire ($2.00)

Total cost - $13.12

Add one more crystal oscillator, mixer, and low pass filter for about $7.00 using the same prices from above and you will have a 20m DSB transmitter for $20.12. I didn't add in the costs for solder and antenna binding posts because I already had them.

Anyone can do this, Larry!!

Too bad you are so ready and willing to prevent newcomers from experimenting and learning the art of RF design! Let'em eat cake!! right?

wa5ben:
", why not add about $5.00 to $10.00 and make an SSB exciter with xtal filters?"

I gave you the web site to go look up what a crystal filter costs - even an experimenters setup. It's $25 alone for a cheap filter with a 5.5 shape factor.

wa5ben:
"Of course, for practically ZERO extra, you can build a phasing SSB exciter. Just a few more parts than a DSB - and TWICE the effective power for the same output Watts. "

Let's see your parts list and costs for this, Larry. I've already told you that I'm building one and have over $100 invested in the VFO alone to get the I and Q signals that are needed. I haven't even started on the rest of the exciter yet!

wa5ben:
"In the much more realistic $50.00 to $150.00 range, there are several DSP options - including special learning systems. THAT is the direction that I would point a kid. Build the RF amplifier, the receiver front end, and the mixer - then let the DSP be the exciter and the receiver. LOTS of "bang for the buck" --- and TOTALLY reconfigurable."

References, Larry! Where? Do you have a web site I can go to and order a fully configured DSP, including circuit board, for $50? for $150? It has to be something I can use directly - if I have to spend another $300 for a programmer that has to go into the cost as well!

Since you have yet to provide ANY parts list, including costs for the parts and circuit board, I am not going to hold my breath waiting for this!

wa5ben:
"When the kid gets into more money, he/she can change to a faster DSP chip and work at a higher IF - or build a fully DSP receiver / exciter. In any case, he/she can have a very capable RX/TX for a shoestring budget - and one HECK of a selling point on his/her resume and/or college application!"

I'm still waiting for that parts list with costs for the parts and for the circuit board for building a DSP and/or DDS transmitter. Remember, your goal is $25!

wa5ben:
"Building a DSB exciter just WON'T get much notice on either a resume or a college application! We may not like it, but that is simple reality."

Maybe not, but knowing what a Taylor expansion is, knowing how it applies to a non-linear mixer, and knowing the triginometric identities to use in evaluating the terms of the expansion certainly will!

I'm still waiting for that parts list with costs for the parts and for the circuit board for building a DSP and/or DDS transmitter. Remember, your goal is $25!

tim ab0wr

 

Now I know who was working in the FCC field office and issued all the pink tickets to Collins KWM-2 owners for using MCW before someone explained to the person what MCW was.

I would stay away from any Collins gatherings if I was you!

I thought you had the concept when you explained the output is carrier + 1000 Hz (USB) or carrier - 1000 Hz (LSB). But then you blew it with the statement about "modulating" a carrier via a balanced modulator. Several of us have tried to explain to you using math and other descriptions that the term "balanced modulator" is named incorrectly and you refuse to accept it. It is actually a MIXER. Your statement also explains why you claim balanced modulators don't create IMD products!

Get this, write it down, memorize it, put it on the wall --

--> BALANCED MODULATOR EQUALS MIXER

--> BALANCED MODULATOR NOT EQUAL TO MODULATOR

When you insert a single tone into a balanced modulator/mixer you get two frequencies out, LO+1000 Hz AND LO-1000 Hz. The injected local oscillator is balanced out and you are left with these TWO FREQUENCIES. One is considered the lower product, i.e. LSB and one is considered the upper product, i.e. USB, as you said. One of them is removed, more or less successfully, by whatever filtering is used and the other is transmitted. IT IS A CW SIGNAL, by definition a continuous wave signal at a single frequency, LO+-1000 Hz.

Even if the carrier is not suppressed well and the opposite sideband is not suppressed well, you only transmit three unique single frequencies, i.e. three cw signals. They are the local oscillator signal (you call it carrier but it is not a modulated carrier), the LO+1000 Hz and LO-1000 Hz. The reason you could hear this in an am receiver is because the LO frequency is supplying the mixing signal instead of a BFO, not because the carrier is modulated.

A modulated carrier would be a system where you actually vary the amplitude of the local oscillator with the 1000 Hz tone, i.e. modulate it. You would also have to un-balance the balanced modulator so the modulated carrier would pass through. This would give you an MCW signal. You will notice, there is no 1000 Hz signal injected into the balanced modulator with this method.

Subtle differences, but extremely important. This is why some of us are so adamant about the need for experimenting and homebrewing, AND LEARNING. You would not learn these concepts and fundamentals with your DSP example. As I said before, we don't have genetic memory where you know everything that has been learned before. EVERYONE must learn on their own what has gone before.

Jim
WA0LYK

 

wa5ben:
"What questions? Your "Well, he got me on that one, so I need to change the subject" nonsense?

The world does not revolve on formulae. My "Electronic Engineers' Handbook" has all of the ones I need - as does my copy of MathCAD. Just as all other engineers, I check my formulae against the source - and then PROVE the results.

I have some very nice sheets set up in MathCAD to run simulations. "

As I said, I didn't expect any answers from you. Most of us know how to look back in the thread and see what we've missed. It's a shame you don't know how to. Would you like some hints on how to do so?

wa5ben:
"The world does not revolve on formulae."

I think we could all tell that you believe that. The truth is that any RF designer I know depends on nothing but formulaes to do an initial design. MathCad is of no use if you don't know what formulas to use and know what they are telling you. Even designing a DSP involves knowing hilbert transforms, fourier series, laplace transforms, etc. That's all mathematical formula, Larry.

I'll stand by my statement about you, Larry. You are a tinkerer, not a design engineer. There's nothing wrong with being a tinkerer. That's what we used to build that DSB transmitter - we used known circuits and put them together and made them work. But then we went back and did the math to calculate bias levels and determine stage class. We wrote transfer functions to evaluate input and output impedances. We analyzed the balanced modulator to see what would be coming out for mixing products (including 3rd order and higher products). We figured the impedance transformation ratios needed to match the mixer and interstage coupling between stages. We calculated the feedback needed on the oscillator for stability. We looked at the math for feedback in the audio stages for stability. It's all math, Larry. Otherwise its spit, solder, and a prayer that things work!

tim ab0wr

 

wa5ben:
"If some want to run modes that inhibit - rather than advance - communications effectiveness (e.g., AM, DSB), perhaps a set of "wideband" frequencies could be set aside for that. As far as I am aware, NO ONE HAS PROPOSED THAT IN ANY FORUM."

I repeat - you are a troll! Apparently you haven't even read the ARRL bandwidth proposal and here you are arguing about it!

The ARRL bandwidth proposal sets aside a huge amount of spectrum for AM - but not for DSB. That's part of the problem with the proposal. The ARRL plan was written by a very limited number of people on an ad hoc committee whose main goal was to open up the phone bands for use by Winlink automatic robots. They used the battlecry of "we need to do this to advance the state of the art and to make room for experimentation!" when in reality, they didn't consider experimentation at all! All they wanted was access to more spectrum.

I know a group of guys whose main pleasure in life is getting on a round-table on AM on 75m. They've been doing it for years. According to you this is an antiquated, obsolete mode that should be banned from the amateur spectrum because it's more than 3khz wide.

Yet consider what those guys have learned, by osmosis if nothing else:
1. Propagation on 80m
They can tell you for just about any day of the
year what times the band will be usable and
when it won't be. Important stuff to know in the
case of an emergency.
2. Sun activity
From selective fading to signal strengths, they
know just about exactly how the ionosphere is
doing. NOAA pays a lot of people big bucks to do
exactly the same thing.
3. Weather forecasting
From the noise levels they can tell you how far
away storms are and how severe they are. This
may seem like a small thing but there are a lot
of weather forecasters on TV that have a hard
time doing any better.
4. Antenna design
Because of the size of the antennas each one of
them has probably had to design in compromises
which still allows for comfortable operating yet
minimizes footprint.

Use of digital signal modes, which most people mute from their speakers, give no indication of any of this since you don't know if you don't hear. Either you can connect or you can't. No. 4 will still apply to the digital modes but the others wouldn't unless special arrangements are made.

You can pooh pooh these kinds of knowledge all you want since you obviously don't care about them, but that doesn't make them any less important.

I will ask again that you find a copy of the Amateur Code somewhere and post it in a prominent place where you can see it every day. Study the "Friendly" piece of it well.
Especially the part that says "consideration for the interests of others"

tim ab0wr

 

wa5ben:
"BTW: Actually, a 1000 Hz tone applied to an SSB transmitter DOES NOT result in a CW signal. It results in a 1000 Hz modulated SSB signal. A true CW signal would not have a 1000 Hz tone impressed upon it. It would be pure CARRIER."

wa5ben:
"Apples are not oranges - and MCW is not CW. Pure and simple. "

For those of you interested in the math (You can skip on past this, Larry!)

Whether you are using high-level plate modulation or an unbalanced balanced mixer:

Assume a perfectly linear balanced modulator with perfect cancellation of the carrier frequency so we don't have to worry about IMD products or carrier leakthrough.

In a balanced modulator, the modulator should be biased so the input levels of both signals have no DC offset so we have Asin(at) and Bsin(bt) as our inputs. The balanced modulator is a *mixer*, which would be better called a mulitiplier! (a and b are 2 * pi* freq)

So we have Vout = Asin(at) * Bsin(bt)

using trig functions this can be represented as
Vout = (AB/2) [ cos (at - bt) - cos (at + bt)]

This is what we know as a typical double sideband suppressed carrier signal.

What we need to do for AM is to add a dc offset into the picture (i.e. an unbalanced balanced modulator or a plate modulated RF amplifier)

So the modulating signal becomes [1 + sin(at)] and the carrier frequency is still sin(bt) (I am using normalized amplitudes here)

So we have Vout = [1 + sin(at)] * [sin(bt)]

This becomes:
[sin(bt) * 1] + [sin(bt) * sin(at)]

The [sin(bt) * 1] term is just the carrier frequency.

the sin(bt) * sin(at) term becomes the same as for the straight balanced modulator.

(1/2)[ cos(bt - at) - cos (bt + at)]

Please note that the carrier term is there all the time. The carrier doesn't vary in strength with the modulation. That's not to say the output voltage doesn't vary, but it explains why you see a continuous full strength carrier on a spectrum analyzer.

Now, what does a single tone into a SSB transmitter do (i.e. a MCW mode)?

It's obvious that we get out two tones from the balanced modulator: cos (at - bt) and cos (at + bt)

The filter is used to remove one of these frequencies leaving us with:
(e.g.) cos (at + bt)

Guess what? The output of a CW transmitter is:

sin(wt) (i.e. a single freq)

Guess what the difference between cos(at + bt) and sin(wt) is?

(hint: what happens when (a + b) = (w)?

In other words, nothing but the difference in phase between sin and cos. Same kind of signal, same frequency.

Perhaps Larry can tell the difference between [cos(at+bt)] and sin(wt) but I'm pretty sure I would have a hard time doing so.

I do need to point out that for an AM MCW signal, it is a different ballgame. You will still get the carrier and the two sidebands. You get three frequencies, not one. That's why the FCC frowns on AM MCW.

All of this also explains why WA0LYK made mention of the Collins KWM2. Guess how it generates CW? Guess why the service manual is so strict in how the rig has to be set up for CW?

tim ab0wr