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Old April 16th 04, 08:40 AM
Pete KE9OA
 
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It sounds like the rectifier diodes in you power supply radiating that
noise. Usually, this type of noise decays pretty rapidly above 600kHz, but
this supply could be using very fast diodes. Connect .01uF caps across each
diode and
(more importantly) bypass each leg of the SECONDARY of the power transformer
to ground with .1uF non-polarized capacitors. This will knock out that
noise, allowing the receiver to be usable down to about 250kHz. If you want
to tune lower than that, increase the value to .47uF.

Pete

"Temporary FL@L&ER" . wrote in message
...
On 12 Apr 2004 23:27:39 GMT, (N0DG) wrote:

If it is this bad I would suspect paint or some other insulating material

on
the top post connections on one of the filter caps.Be usre the contacts

are
clean and tight.
Good Luck.
N)DG
Don


Definately check the cap connections, also check to see that the case
cover screws have at least one external tooth lockwasher to bite
through the paint on both the cover and chassis to ensure a good
ground connection for the cover itself. Sometimes there isn't a good
bond, so you have essentially an unshielded power supply.


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Molon Labe!



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