I've used quite a few different transverters over the years. I changed to
different ones along the way on several bands.
I was using the WA8NLC design on 3456 until Zack Lau KH6CP/W1VT came out
with a design that used better filtering and a separate LO board on thinner
pc board material. The WA8NLC version didn't seem to be sensitive enough on
receive and I had a problem with intermittent oscillation somewhere in the
transmit chain I never was able to cure. The W1VT 3456 transverter design
worked much better and I'm still using it. I had some other design I was
using on 5760, and then W1GHZ came out with a transverter design that I
built. He explained his design choices for it in great detail including
experimental results. I have been using his design for years now with no
problems.
I also did not get great performance from the original 902 and 1296 MHz
transverter boards by KK7B. They worked but I hoped for something better.
Receive seemed a particularly weak point, with a poor signal to noise
ratio. Then W1GHZ came out with his designs for those bands, along with
detailed explanations of designs and choices. I built those and I find them
to be much an improvement. I am using real filters in addition to the basic
circuits, as Paul suggested. The 1296 receiver is particularly hot. I use
preamp designs by WD5AGO on those two bands. By the way, Tom sells pc
boards for his preamps so cheaply he's practically giving them away!
I have the 10 GHz board that Paul now sells. I haven't put it together yet
but I will soon. My current 10 GHz transverter is quite good, so I don't
know if the W1GHZ version will be better or not. Only one way to find out!
As for a couple other bands, the "no-tune" 222 MHz transverter by W1VT is
an excellent performer and I've been using it for years. It can be
configured in several different ways. I like that in a design. And the best
432 transverter I've seen is a design by Ed Krome K9EK that appeared in QST
many years ago. I've also been using that for many years. I've used several
different receive preamps with it. The current one has a measured NF of 0.8
dB.
73, Zack W9SZ
On Thu, Apr 26, 2018 at 6:34 AM, Patrick Thomas <p-thomas@mindspring.com>
wrote:
> Thanks for all the good info. I realize my question is a bit theoretical
> vs. tied to a particular operating scenario. That is deliberate; there is
> no one "best" answer, so I was looking for raw info... also, while
> operating is the end goal for most people, I find tinkering and learning is
> a big part of the enjoyment of ham radio for me. Strangely enough, it's a
> part with far fewer awards and contests linked to it. ;) Anyway, I would
> like to set the next goals for my own designing and learning activities.
>
> With a couple exceptions (W1GHZ for example - thank you!), my experience
> with transverter info online or in ARRL or commercial kits is that the
> write-ups are along the lines of "here is a design you can duplicate but
> we're not going to really explain it beyond a block diagram" or else "here
> is a design we'll explain in depth, but we won't explain WHY these choices
> were made, what others were considered, or what could go wrong if something
> else was done. If anyone is familiar with sources which go this extra
> step, I would be happy to know, by the way! Or if anyone is knowledgeable
> on the subject, I would be glad to work with you to document a design from
> the ground up that is a little more exhaustive, for mid-level DIY neophytes
> like myself.
>
> Linear transponders are even worse to find info on, by the way.
>
> As to "just get on the air," I do have one of the Ukranian transverters to
> experiment with, and I do use it on the air... to paraphrase what others
> have said: "it's a transverter." No slant against them as I think it's
> great to enable people to simply get on the air in VHF... but I would love
> to build (and learn from) my own superior example.
>
> Thanks again, all!
>
> Patrick
> KB8DGC
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