Re: using a K3S with a Q5Signal 144MHz transverter

Bob McGraw - K4TAX

If you are planning on 2M FM then 25watts is adequate.  If you plan to work tropo then 150watts is adequate.   If you plan to work 2M SSB via EME then legal limit is necessary.  All of this depends largely on your antenna system.    If you use a simple antenna then don't plan for more than 100 watts or so.   Feedline quality, meaning very low loss, is also critically important.   For my 10 ele yagi at 50 ft I use 75 ft of 1/2" Andrew hardline and with 150 watts I can work digital EME at moonrise or moonset to take advantage of ground gain.

So what do you intend to do, operationally?


Bob, K4TAX

On 2/26/2021 2:59 PM, Bob Novas via wrote:

Tim -  Thanks for the response.  I don’t know whether to go big (150W/$800) or go small (25W/$479). If I go small, I can always buy an amplifier. If I go big, it would seem harder to reduce power to drive a big amplifier.  But, does anyone actually run much more than 150W on 2M? What does moon bounce take nowadays? Bob – W3DK


From: [] On Behalf Of Tim Hague M0AFJ via
Sent: Friday, February 26, 2021 12:02 PM
Subject: Re: [Elecraft-K3] using a K3S with a Q5Signal 144MHz transverter


I run a Q5 transverter with a straight K3, 28MHz works fine as an IF, I don’t know however if it’s possible to run it up to 32MHz but the new Q5 design uses a clever DLO so Cory may be able to make your transverter dual band, worth chatting to him.
The Q5 unit is better than the Elecraft one, very clean, stable and bomb proof, we have some very big signals in Europe and it copes well.
regarding the drive levels, you are correct, .01mW to 1.27mW, the transverter really only needs about -5 for full output.
The transverter PTT is ground to tx, the K3 key out works fine
the IF is your decision, I like to be able to run 50MHz and 2M at the same time, 28MHz works for me.
just a thought, if I was buying now I’d get the 150W version, easier to loose power than to add it.
73, Tim M0AFJ


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