Re: 3cm receive only system


Martyn G3UKV
 

Hi Dave
The German Octagon (PLL version) was quite good without mods, but it needed 30-45 minutes to stabilise.
I have changed over to the 'Bullseye 10KHz' which claims 2 ppm TCXO stability. It certainly is far better than the Octagon, and after 2-3 minutes power applied, stayed within the QO-100 NB beacon frequency, and didn't need re-tuning on a typical SSB or CW signal. In fact, I had slightly more initial drift from the SDRplay (Mk 1) which is my IF (~739 MHz) receiver.
73 Martyn G3UKV

On 18/02/2021 21:48, Dave Brown wrote:
I want to set up a receive only 3cm system to monitor beacons etc.
 I understand that there are a few LNBs that use a crystal controlled LO and
some of these are being used (with mods) to receive QO-100. As this
application is 3cm receive only I believe I should be able to use the LNB,
mechanically unmodified?
 I have no real limitations as regards IF frequency as long as its below
2GHz . I'm looking for recommendations as to which of the few LNBs available
that fall in this category I should get. If I can get away with no LO mods
so much the better but happy to eventually use an external  frequency source
if I find stability inadequate. Had a trawl through earlier posts re QO-100
etc but no clear picture has emerged re which LNB might be best for this
application.
 73
 Dave, ZL3FJ
 Christchurch, NZ











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