[CQ-Contest] Re: Bandpass Filtering

Frank Donovan W3LPL donovanf at erols.com
Sun Feb 21 22:45:10 EST 1999

Like K3LR, I also use 200 watt W3NQN transmitting
bandpass filters; in my case, between my FT-1000MPs and the
inputs of my 160, 80, 40, 20 and 15 meter monoband 3-1000Z amps.

I also use W3NQN bandpass receive filters at the receiver
antenna input to each FT-1000MP on 160, 80, 40, 20 and15 meters
and I use a W3NQN 10 meter high pass receiver filter at the receiver 
antenna inputs to my 10 meter FT-1000MPs.  W3NQN's receive filters
are a  considerable improvement over my original W3LPL Receive 

You can construct the W3NQN transmitter filters based on his
articles in  May and Jun 1998 QST.  His high performance receiving 
filters will be described in an article in next issue of QEX.

W3NQN constructed each of my filters for a very reasonable price.
If you want Ed to construct filters for you, you can reach him at 

I still use the old W3LPL Receive Filters as a part of receive
quadraplexers that split signals from my Beverages among my
160, 80, 40 and 20 meter stations.  Four bandpass filters are 
simply connected in parallel on the antenna side, and the output 
of each filter feeds the 160, 80, 40 and 20 meter stations 
respectively.  Total loss thru this system is 1-2 dB.

I use an identical quadraplexer design based on W3LPL
Receive Filters to split signals from the Beverages among my
40, 20, 15 and 10 meter stations.

Yes...  Beverages are excellent receiving antennas on 20, 15 and 10
meters as well, but require a preamplifier.

donovanf at erols.com

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