A simple self contained 10GHz(3cm) monitor converter

With the advent of the low cost Quansheng UV-5R VHF/UHF hand-held portable
and Egzumer software to both extend the receive frequency range and add SSB reception, it has become possible to monitor narrow and wide band 3cm signals for little cost, assuming a K-band satellite LNB is already to hand.

This assembly was demonstrated at a Newark Hamfest in 2024 by Kevin G3AAF on his stall, from which enough interest was shown to it becoming a build project for the following years Finningley Round Table.

An early write up on how this was done is here:  http://www.earf.co.uk/easy3cm.html 

For the Finningley Round Table build project, a number of areas needed addressing, not least of which was the safety aspect, and inconvenience of charging Li-ion cells.

Searching through the internet for parts, fully built small Li-ion cell charger/protection pcbs are ludicrously cheap, as are boost converters to provide a suitable supply voltage for the LNB. These have therefore been used on the final design.

A dual output LNB was found to be a suitable LNB. Initially, the thought was to have the option of fitting a TCXO based LNB, but their relatively high cost was rather contrary to the low cost aspiration of the project.
The project would inevitably need a pcb, so space would be available on that if the tcxo was found to be stable enough, which it very much was.

Although the internal xtal doesn’t strictly need removing, it should be in this project because it would otherwise impair tcxo frequency stability. The motherboard pcb allows for several methods of netting, which is why some of the circuit components around the tcxo have been greyed out. 

One thing to note with the software modified Quansheng unit is the dead frequency range of 630 – 840 MHz, so it cannot be used to monitor the narrow-band QO-100 satellite output centred on 10489.750 MHz (unless a 26MHz tcxo is fitted to the converter, in which case the centre beacon will be down-converted to 739.750 MHz).
Signals from the satellite are just audible via the converter without recourse to a dish, which may be of interest to some listeners.