Topband: BCB High Pass Filter

jeremy maris jeremy at
Thu Mar 3 19:55:34 EST 2016

I noticed a bit of BC inter-mod so built a 9 pole Chebyshev high pass filter dead bug style in a small diecast box with some internal screening made from double sided pcb stock.   I designed it with the excellent RF filter design package from Iowa Software, and used an LC meter to get the capacitor and inductor values correct. Only took  a couple of hours to make out pf the junk box using polystyrene caps and small toroids  - designed for 50 ohms with corner frequency 1.5MHz and 0.2dB passband ripple.

The filter response was almost exactly as the design showed, as measured on the G4AQG spectrum analyzer - at least 50dB down at 1 MHz  and a local broadcast station on 693kHz station is  now almost undetectable compared to 70dB over S9 or more without the filter.   
Inter-mod has gone.

Jeremy G3XDK/G4AQG

> On 3 Mar 2016, at 15:59, Roger White <rwhitetexas at> wrote:
> Anyone have a BCB High Pass Filter that they would recommend? Seems like there were a number of sources for these a number of years ago, but Google only came up with a few now. 
> Roger White W5RDW
> Murphy, TX
> _________________
> Topband Reflector Archives -

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