Low-Pass Filters

Doug.Grant at analog.com Doug.Grant at analog.com
Thu Jul 30 20:05:00 EDT 1992

I bought some low pass filters from B&W - the guy who took the order had never
heard of them until I gave him the part number and prices from their price
list. I tested them on a network analyzer, and they looked great - the 80M LPF
had a nice null at 7 MHz, etc., so I used them in my multi-2 in ARRL this
The 15 M unit went up in smoke Sunday morning. I opened it up, and the input
coupling capacitor is a teenyweeny little dinky thing - no wonder it smoked
(I'm only using a "street-legal" Alpha 76A, so don't get the wrong idea).
Thank God for 1/4 wave stubs.
I sent the 80/40 M filters back to B&W (at $40 each, I decided it was worth
getting my money back, and they gave me a refund). They don't make a 20M
filter. I'm going to build a set of KW bandpass filters from scratch.
Doug, K1DG

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