[TowerTalk] Band Pass Filter Question

[Jim Brown]

On 11/27/2020 2:00 PM, RVZ via TowerTalk wrote:
> I realize it's best to install Band Pass Filters on both the 
> transmitter and receiver.  But if only one or the other can 
> be installed, can you tell me which of the two usually 
> provides the best attenuation?

The most common bandpass filters are rated for 100-200W, PROVIDED that 
they are inserted at a point where they are inserted is well matched, 
for example between transceiver and tuner or transceiver and amp, so 
they will work on both TX and RX.

The major limitation of these filters is that they can't kill harmonics 
produced in a power amp -- that requires either stubs properly placed 
along the feedline or high power bandpass filters. Here's a survey I did 
my lab of the bandpass filters available to me in 2014. Near the end is 
a link to a page of links for individual measurements.

http://k9yc.com/BandpassFilterSurvey.pdf

This piece on stub placement also ran in NCJ. The second link is to 
slices for talks I gave at Visalia, Pacificon, and to several local clubs.
http://k9yc.com/LocatingStubs.pdf
http://k9yc.com/StubPlacement.pdf

73, Jim K9YC