- Chinese ADF4351 signal source
Re: Chinese ADF4351 signal source
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Check the value of the charge pump resistor also
I just took delivery of an ADF5355 synth (against all my principles, from China) and it had the same really poor 25MHz CXO on board. I tried it, before doing the mod and it was unbelievably off freq - some 1000 ppm.
After converting for external 10MHz source (which is not really optimum frequency for that chip, but does work if you enable the ref-doubler) seems to work fine, but will benefit from the DC supply decoupling mods.
You have to remove the L feeding DC to the on board OCXO. Then move a link or two to get your external input
The main problem I have with this module is that it does not have an input for external 25MHz source. There is an SMA connctor marked MCLK but this turns out to be an output from the internal (crap) 25MHz reference which is a mile off 25MHz and not very clean..
Otherwise ist seems useable.
Robin Szemeti - G1YFG
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