[TowerTalk] How to test functionality of bandpass filters?

Jim Brown jim at audiosystemsgroup.com
Sun Dec 22 12:54:00 EST 2013


On 12/22/2013 7:16 AM, Steve London wrote:
> Might also be good to point out that the source and termination 
> impedance should be matched to the filter - probably 50 ohms. 

Another simple test I used years ago before I had HP instrumentation was 
to transmit through them at 50W or so into a 50 ohm dummy load and 
measure the SWR over the width of the band. SWR higher than about 1.25:1 
suggests either mis-alignment or component failure, which often results 
in increased dissipation and (more) component failure.

It's also a good idea to compare your test results with the mfrs 
specs.Some filters, like the Dunestars, intentionally don't cover the 
entire width of the wider bands (80M and 10M).

73, Jim K9YC


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