I purchased two Ukrainian transverters and made some measurements. Their
Noise Figure was 10 to 15dB, the S21 gain was +12dB and the S11 input
impedance was awful (I forget the exact impedance) but that was correctable
by adjusting a coil. The LO frequency was fairly stable for my pair but
there were mixing products all over the place. One right next door to the
IF carrier.
I agree with Steve, nice enclosure but poor performance.
73,
John
N2HMM
-----Original Message-----
From: VHFcontesting [mailto:vhfcontesting-bounces@contesting.com] On Behalf
Of Steve(K1IIG)
Sent: Wednesday, April 25, 2018 2:12 PM
To: VHF Contesting; N1BUG
Subject: Re: [VHFcontesting] What separates a decent transverter from an
awesome transverter?
Paul, Most of my xverters are Demi up to 10ghz and I like them for few
reasons. They hold up well mounted topside, they are very stable with the
Apollo board and support is excellent. The micro-lo does drift esp outside
but the xtal control
does have a plus, it is clean. All the synthesizers I have used are not and
can cause havoc if you have close by ham neighbors. For that reason I do not
run my 432 beacon with syn boards instead I am using a clean transceiver
that seems to hold freq
within 100hz. Of course you can spend some more $$ and go with a Kuhne but
should it break it will take a long time to get fixed not to mention
shipping charges.
I just purchased a couple of transverters from the Transverter Store,
http://transverters-store.com/ and would not recommend them. One was
unusable and the other required a preamp. Both LO's were way off freq. The
best I can say is they came
in a nice enclosure. It is a cheap way to get on the air but you get what
you pay for. Cheap price, Cheap product. Check out the complaint on the net,
I should have. I would not put them in the decent category let alone the
awesome one.
Before you spend more $$ I would talk with Steve at Demi and see if he has
any suggestions.
73'
Steve
> Steve,
>
> I may have missed something last time I checked but it looked like
> DEMI had options to cure drift in that manner for 450 MHz and down,
> 2.3 GHz and up, but nothing for 903/1296. The ZL2BKC board seems to
> fill the gap. While the various phase locking solutions seem fairly
> priced for what they do, it can be the straw that breaks the camel's
> back for those who arguably shouldn't be contemplating these bands
> in the first place. :-)
>
> I decided my $25 crystal heaters probably can't do much for the
> Micro-LO which is why I pushed the DEMI onto the more-or-less-reject
> pile. Nothing against DEMI, just not a good option for me with that
> much drift. It remains to be seen what I can do for the old UHF
> Units but hopefully I can improve it somewhat.
>
> 73,
> Paul
>
>
>
> On 04/25/2018 07:47 AM, Steve(K1IIG) wrote:
>> PAUL,
>> The Demi Micro-Lo is notorious for drift which of course they have a Syn
>> board you can replace that requires 10mhz to lock it. You can buy an
>> 10mhz
>> OCXO for $10 on the internet that will work fine to lock it.
>> Take a look at this site https://zl2bkc.com/ which also has a replacement
>> board for the Micro-Lo.
>>
>> 73
>> Steve
>>
>> --------------------------------------------------
>> From: "N1BUG" <paul@n1bug.com>
>> Sent: Wednesday, April 25, 2018 3:20 AM
>> To: "VHF Contesting" <vhfcontesting@contesting.com>
>> Subject: Re: [VHFcontesting] What separates a decent transverter from an
>> awesome transverter?
>>
>>> One thing I didn't see on your list that always concerns me is LO
>>> drift. Drift can be a problem for any weak signal work, say a long
>>> haul CW sked during a contest. If you want to do some of the digital
>>> modes it can become a critical issue, even a show stopper.
>>>
>>> Since I can neither afford nor get my head around the complexities
>>> of GPSDO locking, I am always concerned about crystal oscillator
>>> drift in transverters. Usually I do the best I can to build and
>>> install some type of crystal heater... with mixed results over the
>>> years.
>>>
>>> Sometimes I find things that surprise me. Last summer I measured
>>> drift on two 1296 transverters: a relatively ancient UHF Units and a
>>> relatively newer but not current generation DEMI, both as yet
>>> unmodified. Over a temperature range that caused the DEMI to drift
>>> over 6 kHz, the UHF Units moved just a bit over 200 Hz! I know which
>>> one I will be using if I ever get the rest of the stuff together for
>>> 1296.
>>>
>>> Paul N1BUG
>>>
>>>
>>> On 04/24/2018 10:31 PM, Patrick Thomas 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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