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Re: [VHFcontesting] What separates a decent transverter from an awesome

To: Patrick Thomas <p-thomas@mindspring.com>, VHF Contesting <vhfcontesting@contesting.com>
Subject: Re: [VHFcontesting] What separates a decent transverter from an awesome transverter?
From: Greg Mills <gmills@frontiernet.net>
Reply-to: Greg Mills <gmills@frontiernet.net>
Date: Fri, 27 Apr 2018 03:02:38 +0000 (UTC)
List-post: <mailto:vhfcontesting@contesting.com>
Well here is a collection of thoughts, which turned into a rover list. Once you 
build two, it gets complicated.

A good sequencer, or at least a sequence of dekeying steps that protects the 
receiver.Transverters for all bands have the same interface connections. 
Easy way to hook up the external amplifiers.Good LNA's...linearity and NF. Not 
too much gain.Easy way to adjust for the LO and/or IF drive for different types 
of mixers. I made a little board for pi pads, or footprints in the mixer 
section at least.
Light weight 19" rack mount chassis.A controller than can easily switch between 
a stack of transverters, routing IF/power/key/antennas, etc.
5 years of building, testing, breaking, rebuilding, testing, burning down 
LNA's, etc. Then it might be ready.
A source of PVG-612 opto isolators.
Good antennas and accurately pointing them within a few degrees. This is as 
much work as the above.
Never use a switcher for anything. 
Ability to troubleshoot in the field. Make a troubleshooting guide, like a 
cheesy checklist, "set the onoff switch to the ON position".
A retired guy to also build stuff.
PLL LO's.
Machined surplus band pass filters. But... my 3 GHz transverter has printed 
filters, and the up/down converted spectrum looks terrible, but if we work 
someone on 2304, 3456 is just as easy. Bought the basics of it at the Rochester 
hamfest in 1998, via K2DH.
I designed the upconverters for 10 dB below P1dB, but the PA's are run at P1dB. 
Anything on the air is > nothing. Let it rip.

Greg - K2LDT/R


      From: Patrick Thomas <p-thomas@mindspring.com>
 To: VHF Contesting <vhfcontesting@contesting.com> 
 Sent: Tuesday, April 24, 2018 10:31 PM
 Subject: [VHFcontesting] What separates a decent transverter from an awesome 
transverter?
   
Hey all,

Subject more or less says it all... I guess better sensitivity, lower noise, 
better selectivity, and better linearity are the essentials in vague and 
relative terms, but what attributes do you look for in a REALLY GOOD 
transverter?

Or for those who have gone further into making them... what components, 
construction techniques, etc., make a difference?

Partly this is a question I hear a lot and only have a vague notion of how to 
answer other than "obviously the expensive ones are better... somehow." :)

And partly it is a request for topics for self-guided study/experimentation as 
I attempt my own homebrew projects.

Many thanks,

Patrick - KB8DGC
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