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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