Hello everyone,

I have a question...or a series of them I suppose. I'm trying to wrap my head around some concepts regarding filters. I have recently bought and built a neat little RockMite 40. I bought 7.030 crystals for it and it works great. So good that I can hear what seems like 4k (sounds like a good number to use) of bandwidth and a multitude of signals piling up.

My setup for the little RockMite is a random balanced wire through a MFJ Versatuner. It tunes just fine and all is good there.

So.. I'm trying to improve the filtering capabilities. Would I be wrong in assuming that using a resonant antenna for 7.030 would reject some of the unwanted QRM? I hope that wasn't a 'knee-slapping' funny question, but it came to mind.

Further, I noticed this filter kit: http://www.idiompress.com/scaf-1.php?ad=7&ref=e
The filter appears to be an audio filter.

Utilizing an audio filter doesn't seem, in my mind, to be the same as a filter that narrows receive frequency. While the audio filter that is demonstrated on the above link does well at filtering out unwanted signals on an already narrow frequency bandwidth, it doesn't appear to narrow the bandwidth that is fed to the audio in the first place. My guess then, is that if I bought that kit and put it together, I would have the ability to filter out signals that were transmitting on the frequency I was intending to hear. In other words, I could theoretically filter out a signal on 7.030 for a signal on 7.035, and since my little RockMite is 'Rock Bound', I couldn't attempt to contact the station since my transceiver isn't capable of reaching that frequency.

Am I in the neighborhood of the ballpark? The city in which the ballpark resides?

If someone can take the time to affirm or 'set me straight', I'd really appreciate it. Further, if someone has a link to a filter that would work for what I'm intending to do, that would be pretty excellent as well!

I have a TS-2000 I need to make the MARS mod to so I can transmit on 4038.50... Has anyone done this or is there any advise on this mod.?

You can reach me at w4jrv@yahoo.com or call me on my cell at 843-812-7949

Thanks
Jeff
W4JRV

Hi I have an MFJ 1026 that I have been using for a while without issue.

Today I notice when the unit is on, I get no signal at the radio regardless of the position of gain/phase knobs. As soon I shut the unit off, I see an S9 signal at the radio.

I always use the T/R control and I can hear the relay engage/disengage when I transmit. The internal lamp does not light up, and the SWR at the radio is fine.

Please help!!

Kenwood TM733 CTCSS Tone Intermittent
I found loose solder connections at IC-408 on the TX-RX Control Unit board. The board is located behind the front panel and behind the plastic cover behind the front panel. It is the vertical board with Mic and Data plugs and two, white ribbon cables, left of center. IC-408 is a small, three terminal IC with soldered heat sink tab, just above the screw that holds the left end of the board. I resoldered three terminals and the tab and then installed a 1/8 inch wide copper strap from ground pad on front of board to one directly behind it, on back of the board. This cured the intermittent dropouts of the CTCSS tones on transmit. WA0RLY,May11,2013

Hi experts! I am making a RF transmitter

and i need to make a synthesizer as a l.o to feed my mixer 2442MHz and 5dBm need. I talked to mini-circuits and the proposed to me this:http://pdf1.alldatasheet.com/datashe...2554A-119.html

This a chip alone. As i understand i need more "devices" to have a complete synthesizer. Can you please help me what more i need?User interface,microcontroller etc... about the ADF4118 what is this and how the chip is connected with this.? i am confused because i am noob in this field:confused:

George

Hi, i am working on a multiband hf transceiver, and i want it to be a high performance simple to understand all mode solid state transceiver design, made up with robust and easy to find component, i am currently studying a design, i wanted to take advice from all home brewing hams that how can this design will work better and will have a much better quality receiver, transmitter and frequency coverage, low drift, more efficient so that up to 10-25 watts qrp RF output can be made to run on car battery. Actually I just want a design which performs really well on hf also which has all the important stages separately and does not compromise for anything, an all band transceiver design. All I want to make is a circuit design which can be replicated again and again with easy to find components but it should also perform well. If anyone have any of such good design for an hf transceiver then please send me the details and also I would really appreciate if anyone can edit the design details of “HMY2K8 transceiver” with the parts easily available also with addition of additional circuitry or stages for a better performance out of this transceiver design...looking forward for your reply soon..
I am attaching designs details as zip file kindly open them with WinZip or WinRAR software’s.
The original design of this transceiver has the ic 74HC4053 Triple 2-channel analog multiplexer/demultiplexer and ic TA7358 and instead of these I would like to use the ic MC1490 and MC1496 from Motorola to this transceiver,
I would like it to have the features--
Frequency coverage-- RX
0.030– 30.000 MHz continues receiver
Transmitter--TX
1.800– 1.999 MHz
3.500– 3.999 MHz
7.000– 7.300 MHz
10.100–10.150 MHz
14.000– 14.350 MHz
18.068–18.168 MHz
21.000– 21.450 MHz
24.890–24.990 MHz
28.000– 29.700 MHz
Modes --- SSB---USB, LSB, CW, RTTY
Transmitter Output power-- SSB, CW, RTTY 10-to-30 watts
Receive system --super-heterodyne
Thanks and 73’s
Vu3sxn shubham tiwari
Email - vu3sxn@gmail.com

Attached Files

• multiband transceiver hmy2k8 .zip (1.90 MB)

I need the operating manual or schematic diagram. Thanks

hi all i am looking for a spanner wrench for my yaesu vx6 r so i can take the nut off of the sma antenna connector a friend of mine is doing a repair on it

My FT-990 takes one hour to bring it's noise level on 14 MHz from S9 to S3, Any ideas?
73, Gary, K4FY

I have two older HTs a 580 and 160 (as in the post title), When they went into storage they were working fine, now I can't get them to take power even from a direct source, I need a link to some specifications so I can begin the troubleshooting process, anyone have any suggestions?

Tnx,
KD1MP

Just got this unit for my car from ebay, and I have no manual, does anyone have one they can send me, or more importantly just tell me how to program the unit with my local repeaters? Or set it up for dual VFO?

Tnx

KD1MP

So I got a nice YO-301 station monitor from an SK. I'd like to use it for performing a two-tone test, but the unit is labeled for 500 watts maximum power.

Now, I think I have the circuit diagram, and I've not taken the covers off yet, but before I do, does anyone have a suggestion for increasing power handling to accommodate my AL-80B?

There looks like there's one capacitor for the sample pickup on a loop in the coax - would a 3 db attenuator in series with that capacitor do the job?

My IC706 turns itself off every few minutes, especially when 'cold' if left on for a few hours it seems more stable. Has anyone encountered this problem.
cheers
Mike vk6zm

I have the radio at the Ham Shack in Derby, KS as they came highly recommended. I found out today that Yaesu doesn't have this part in stock any more, so I'm looking for an FT-840 'tech special' with a working crystal filter in it. If anyone knows where I might find one, my email address is good on QRZ.

Thanks!

Does anyone have a source that shows the circuit equations for a pi attenuator and which lead to the N= Vin/Vout and R1=R3=R0(N=1/N-1) and R2 = (N^2-1/2N) equations?
I would like to see how these equations are obtained.

I know it gets a bit messy and that is probably where I made my mistake...somewhere in all the parallel resistors calculations....but I just cannot find my error.

Thanks,
73s