[TowerTalk] Brick wall filters

[K4SAV]

You can whip one up very quickly with Elsie.  It's a free program and 
very simple to use.  Get it here along with some other good stuff on 
this page:
http://www.tonnesoftware.com/index.html
The freebie student version is very good and will allow you to build 7th 
order Cauer (elliptical) filters which will do the job.  With the 
registered Pro-Lite version you can design 10th order filters and make 
an even better filter. 

For cores, you can use Amidon T80-2 ($1.20 ea) wound with #20 wire to 
make inductors with Q's ranging from about 200 to 270 for inductors of 3 
to 8 uH, which is about the range you will need.

I built a 10th order filter designed with this software.  It removed all 
my intermod problem on 160 meters, even with a radio station 1500 ft 
from me.

Jerry, K4SAV


MIKE DURKIN wrote:
> Any one have schematic/values for a AM Brick-Wall Filter??
>
> Or will a open 1/4 pice of coax do ok for high pass ??
>
> KC7NOA
>
>
>