[Fourlanders] DCI Bandpass Filter - High Reflected Power

[Jim Worsham]

I have a filter for 222 MHz that you can use.  It is a military surplus 2
cavity job that was tuned on a network analyzer to 222 MHz.  I have never
used it but it should do the job.  I will bring it to the mountain unless I
hear otherwise.

73
Jim, W4KXY

It doesn't matter how beautiful your theory is, it doesn't matter how smart
you are.  If it doesn't agree with experiment, it's wrong.
Richard P. Feynman
-----Original Message-----
From: fourlanders-bounces at contesting.com
[mailto:fourlanders-bounces at contesting.com] On Behalf Of Brian McCarthy
Sent: Tuesday, September 07, 2010 9:27 AM
To: Fourlanders
Subject: [Fourlanders] DCI Bandpass Filter - High Reflected Power

I know that we have had occasional problems with filters used for the
contests. My DCI-223.5-3H has developed a problem. With 30 watts in at
222 MHz I get 10 watts returned. I have opened up the unit. I found no
obvious problems. I closed it back up, but made sure to carefully
clean the center contacts on the SO-239's (MEK and cotton swabs). No
change. I guess I will open it up again and check for hairline
fractures, or bring it to work where I can reheat the joints with one
of the monster soldering irons.

One added data point of information, I NEVER feed the output of the
amp through the filter. I always use it between the transverter and
the Lunar Link.

Does anyone have any other suggestions?

When we had trouble before with DCI filters, what were the failure modes?

Does anyone have a similar filter appropriate for 222 MHz that I could
conveniently borrow?

Thank you!
Brian
NX9O
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