I'm sort of surprised that I can't buy a matched mast mounted LNA / transverter
(or perhaps RX converter) combination for amateur radio use on the VHF bands.
(Or maybe they exist and I haven't encountered them or looked hard enough ?) As
much as I enjoyed tinkering with my Spectrum analyzer, attenuators, cavity
filters, signal generators etc while getting my 144 MHz terrestrial system at
my home station more or less working to my satisfaction it would have been nice
have been able to have the option to buy a matched set of equipment with
published performance specs. I realize adding cavity filters would likely
require some additional effort on the part of the users but presumably their
could be some allowance made in a design for this (along with likely cable
losses and other factors.)
Maybe spending time tinkering with things is part of the fun for many people or
perhaps the market is just to small for this type of system.
73
Mark S
VE7AFZ
mark@alignedsolutions.com
604 762 4099
> On Apr 25, 2018, at 8:27 AM, Kevin Hobbs <ve3kh@cogeco.ca> wrote:
>
> I think one needs to look at the bigger picture ... the transverter is less
> important than getting the entire system right. Often the transverter is
> located many dB of coax away in the shack where signals are already lost.
> Many people then add a preamp closer to the antenna that overdrives the
> front end of the transverter ... it took me years of experimenting with
> preamps, cavity input preamps, filters, cable loss, transverters etc before
> I found what played together nicely for me for weak signal / EME work in
> city locations with large in and out of band signals complicating matters.
>
> These days it costs little $ to input a rock solid frequency reference, and
> with a good external preamp (and possibly filter), the transverter itself
> becomes a far less critical component in the system ... IMHO
>
> 73 Kevin VE3KH
>
>
> -----Original Message-----
> From: VHFcontesting <vhfcontesting-bounces@contesting.com> On Behalf Of Sean
> Waite
> Sent: April 24, 2018 11:56 PM
> To: Patrick Thomas <p-thomas@mindspring.com>
> Cc: VHF Contesting <vhfcontesting@contesting.com>
> Subject: Re: [VHFcontesting] What separates a decent transverter from an
> awesome transverter?
>
> I enjoy some of the features on the SG Lab transverters. You can set jumpers
> to switch the LO, and output in a different part of the band (moving from
> the sideband portion of 33cm to the FM portion, for instance).
> It's easy to get either dedicated RX port or a split TX/RX port. 10MHz ref
> is optional but as a dedicated port. Can be switched via RF or PTT (this is
> debatable, since you're hot switching relays in this case I think).
>
> The DEMI 3cm transverter I have has a nice relay feature, you can hook up a
> 24VDC relay as a T/R relay and drive the transverter with 12VDC, it'll fire
> a cap to give the relay enough juice to switch even with only 12V in.
>
> 73,
> Sean WA1TE
>
> On Tue, Apr 24, 2018 at 10:31 PM Patrick Thomas <p-thomas@mindspring.com>
> wrote:
>
>> 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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