Topband: BCB Filter Recommendation?

[Jeremy Maris]

Make your own!

Use this site to design your filter.

http://www.iowahills.com/9RFFiltersPage.html

Attached are the values I used back in 2016 when the G4AQG FT-1000MP had intermod problems with a new Beverage.

I built a 9 pole Chebyshev high pass filter, designed with the excellent RF filter design package from Iowa Software, and used an LC meter to get the capacitor and inductor values correct. Caps were made from polystyrene and inductors wound on small ferrite torroids..

Difficult to see from the (ancient!) spectrum analyzer picture but the filter response was almost exactly as the design showed.
No labels for stop-band but it was 10dB down at 1579kHz, 50dB down at 1000kHz and at 693kHz was in the noise, at least 70dB down, almost undetectable compared to 60dB over S9 or more without the filter, and the  intermod was gone.


> On 16 Apr 2020, at 19:34, Edward via Topband <topband at contesting.com> wrote:
> 
> Greetings, 
> 
> I am getting clobbered by a local BCB transmitter, making 160M unusable, even with a dedicated RX antenna. 
> 
> As for filters, I have narrowed it down to the ICE and the Kiwa. Kiwa seems to be the more serious filter, as they publish their specs in great detail. ICE does not. 
> 
> Any other filter I should consider besides these two?
> 
> 
> Thanks,
> Ed 7Z1ES
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

73,


Jeremy Maris
G3XDK / G4AQG