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.
http://iowahills.com/9RFFiltersPage.html
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@verizon.net> 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
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