Re: 1296MHz LMW Transverter Troubles


geoffrey pike
 

Hi Jim,
My first 23cm transverter in 1980 something, anyway the problem with these was the 6watt PA stability. Stability from my point of view in the Rx converter was always OK. I would initially try and re tune it. It does have from memory quite a few teflon trimmers and it may be worth trying
BUT you may wish to buy a LNA from Epay that covers 23cm and go straight into the mixer with it, If this works then you could look at some 23cm specific filtering later and other refinements.
Good Luck
Geoff
GI0GDP

On Monday, 3 May 2021, 18:54:24 BST, jimbod1973 . <jimbod1973@...> wrote:


Hi all,

Well I've discovered the reason I heard nowt at all on 23cm yesterday.

I'm using an old LMW transverter and the 2nd RF stage of the RX converter hoots (I think the 1st stage might be dead altogether) Looking at the layout its not that surprising - there is no shielding around the individual stages and not many ground stitching vias, so I would expect it to lack some stability.

Despite efforts today to add some shielding made from bits of PCB I haven't yet succeeded in taming it. This is a really old design now though (think I built it about 25+ years ago), which has me wandering if I should look at an alternative, more recent approach and just use the remaining parts that work OK (the LO chain, PA and switching all work quite nicely)

The RX conv in its present state would make quite a useful test source for 13cm & 9cm when I eventually get going on those bands.

Suggestions please?

Thanks
Jim G0MPP
IO93CT

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