R2400 unstable

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leaper54
New User
Posts: 14
Joined: Thu Jul 31, 2014 5:35 am

R2400 unstable

Post by leaper54 »

I have managed to adjust the TCXO to correct frequency error. Thank you for the prior comments back in April.
In general, the unit works fine for ham radio work. The frequency error still seems to jump around quite a bit.
Both the Freq. Error and Deviation bar graphs swing + / - around zero. I'm thinking a power supply issue?
Anyone seen this before? On my Freq. counter, the source is very stable.
jry
Posts: 481
Joined: Fri Feb 06, 2004 3:14 pm

Re: R2400 unstable

Post by jry »

I would think about updating the fan if it's the original brush type. ( it was a really good fan in its day ...about 25 years ago )

The size is standard and the newer versions are brushless.

Would also add some additional filtering like an LC or RC filter in the fan power leads. The value of R would be low ...you may want to do some testing so you do not drop too much of the 12vdc to the fan. The R value depends on the fan you select and it's current draw. Higher CFM fans will pull more current.

Bigger the cap the better ...1000uf 16VDC but anything will help isolate the noise from the fan which shows up as jitter in the synthesizer output.

This helps remove any residual FM and AM on the gen and receive as well
leaper54
New User
Posts: 14
Joined: Thu Jul 31, 2014 5:35 am

Re: R2400 unstable

Post by leaper54 »

Thank you all! I simply added a 1000uf cap on the fan leads, and it is MUCH better. The fan had already been replaced with a brushless model. _ have ordered an inductor to add also.
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