Last call for group buy of F6BVA QO-100 system PCBs etc
Neil Smith G4DBN
As previously mentioned, I'm doing a group buy of PCB sets for the F6BVA QO-100 up/down converter and MW7ic2725 PA.
This version of Michel's design is about making a simple standalone unit for use over QO-100 without needing a computer or SDR dongle, and without tying up the TX side of a 13cm transverter. Ideal for a go-box with a 2m/70cm SSB rig and POTY-equipped dish.
There is already enough interest to do a group purchase of the components. I will be providing some English-language construction notes. The set of two PCBs is likely to cost around £40, perhaps a little less if demand is high enough. Not sure of component cost yet, but the Minicircuits mixer at £13 and MW7ic2725 at £50-ish are the only expensive bits.
You'll need a local osc with two selectable frequencies. An SV1AFN or even a Chinese ADF4350/51 would be good enough for QO-100 usage.
Sorry there isn't a converter-only option as the economics of fancy SHF laminates and finishes mean we have to buy both boards, but you may be able to find a home for the PA PCB if you don't need it.
For clarity, the older version was full-duplex, but this V3 is designed to work with a simple half-duplex transceiver. On 2m, you can use a DF9NP LO using one of the control pins, but for the other bands (and also 2m) you can use an SV1AFN or Chinese ADF4351 with a tx/rx changeover flipping the frequency via a pin on the controller. I'll be using an SV1AFN board. Not decided about the controller yet, might just use an 8-pin PIC and PSU and TCXO on board, but that would just be reinventing the SV1AFN controller. We'll be supporting this through the IO group at https://groups.io/g/BVA-transverters-uk/message/356 which you are welcome to join.
If you are interested, have a look at the document (in French) at https://f6bva.pagesperso-orange.fr/Technique/Satellite/Station%20V3%20QO100%20complete.pdf
If you'd like to join a group purchase of the PCBs, with optional tin box, milled aluminium PA box and full or part component set, please email me direct to email@example.com with title QO100 so I don't miss the message!
I'll be finalising the order to send to Pierre-François in the next day or two, but the ultimate cut-off will be when he submits the order to the pcb fab. I don't expect there will be a second tranche.
Just a quick throw into the air. I currently run a lashed up up-converter from 432MHz to 2400MHz using a SKY-60LH mixer and an ADF4351A LO at 1968MHz – it drifts as it has a crap 25MHz reference crystal. Some amplification up to 500mW to drive a 20w SG-Lab amp. It needs a lot of improvement. (stable reference <the RX LNB one> and sharp LO filter) Prime mover is an IC-706MK2g – I did use an SG-Lab transverter but a hell of a waste and a pain.
RX is down converter from LNB IF 739MHz to 144MHz (FT480) – steady as Gibraltar. I have been having thoughts about changing the LO in this to 307MHz to give /RX IF of 432MHz to give full simplex on a non satelite equipped radio – ie the 706.
Anyone done anything similar ?
Regards to all, Colin de G8LBS.
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From: Neil Smith G4DBN
Sent: 14 March 2021 13:54
Subject: [UKMicrowaves] Last call for group buy of F6BVA QO-100 system PCBs etc
As previously mentioned, I'm doing a group buy of PCB sets for the F6BVA