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I did the 26mhz and 27.5 mods on one a while back giving me aprox 980mhz and 438mhz for 10.4ghz.
Can't find your Cat talk Brian on the original mods.
I take it the Octagon OTLSO PLL Optima is ok for locking mods.
P.S Have gone back to other posts, possible boards for Ref input, mods etc.
I have built one up, I haven't got all the right parts so a little bodging was needed, especially around the BNC/F connector, but it seems to be working. Needs cleaning up a bit. I will design an update based on what I have learned building the prototype. What to do next, not sure.
- PCB_Bias_Built.jpg (391.1 KiB) Viewed 530 times
I should think that locking would be fine on the OTLSO.
I've been looking around for crystals to bring the NB section into 432MHz, to use an FT817. For the 27MHz version, the best I've found is 27.85MHz, which brings the NB section to 432.605MHz. I don't know if the 27MHz version is stable with that high a crystal.
For the 25MHz version, the best I've found is 25.78125MHz, which brings the NB section to 434.862. Again, I don't know if it would work. It would also bring the WB section down that low.
You'd probably have to use reverse DDS to externally lock those frequencies.
Unfortunately both crystals are from Mouser, so I'll have to wait until I need enough stuff to get the free postage.
Also Brian for link, that's the one and your information on modifications and limits.
Have done some catch up today on Batc and other forums.
I gather that the Si5351A kit supplied by QRP Labs can be locked to 10Mhz.
Link to that post
https://groups.io/g/QRPLabs/topic/is_th ... 0,26746229
Square wave output will cover 25 - 27mhz etc.
I have no experience with the Si chips, would this be too noisy?
That is if the concept worked