Re: Chinese ADF4351 signal source


Robin Szemeti - G1YFG
 

Check the value of the charge pump resistor also

On Sat, 26 Dec 2020 at 11:58, Andy G4JNT <andy.g4jnt@...> wrote:
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.



On Sat, 26 Dec 2020 at 11:54, Andy Talbot <andy.g4jnt@...> wrote:
You have to remove the L feeding DC to the on board OCXO.   Then move a link or two to get your external input



On Sat, 26 Dec 2020 at 11:41, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
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.
Dick


--
Robin Szemeti - G1YFG

Join UKMicrowaves@groups.io to automatically receive all group messages.