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[CQ-Contest] stubs vs. bandpass filters

Subject: [CQ-Contest] stubs vs. bandpass filters
From: w2up@mindspring.com (Barry Kutner)
Date: Fri Jul 2 21:10:30 1999

Scott - I believe you are correct. I spoke with Mike at ICE today, 
and without putting number on it, he said "adding the second filter 
would produce an additive effect somewhat less than twice a single 
filter."  I interpret "somewhat" closer to 20 db than 6 db. 
Also, the 170W present on antenna 2 with 1500W transmitted on 
antenna 1 was a theoretical model generated by EZNEC, placing a 
50 ohm load in place of the source on the second antenna 
(suggested method by W7EL). Mike suggested it would be 
significantly less, which I intend to verify once the antenna is up by 
putting a wattmeter in the line of the rcve antenna and connecting it 
to a dummy load (NOT a transceiver!) while transmitting on the first 
antenna.
I'll report back my findings once the antenna is up (probably not 
until fall with the hot wx we've been having!)
73 Barry

On 2 Jul 99, Scott Ellington wrote:


> That said, however, cascading a second "40 dB" filter with the first will
> probably yield a big increase in attenuation.  Perhaps not 40 dB, but probably
> more than 20.  My guess is that with two of the ICE filters, the limiting
> factor would be leakage around the filters, unless great care is taken.
> 
> 73,
> 
> Scott  K9MA
> -- 
> 
> 
> Scott Ellington
> sdelling@facstaff.wisc.edu
> Madison, Wisconsin    USA
> 
> 
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--
Barry Kutner, W2UP              Internet: w2up@mindspring.com
Newtown, PA         FRC         alternate: barry@w2up.wells.com


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