Originally Posted by
HEATHROW DIRECTOR
So what form did the notch filter take? Did it plug in to the audio output or was it professionally fitted much farther back in the receiver? If you have interference on audio a notch filter is of little use unless the interference is a single tone or some sort. I suspect your improved receive performance was derived more from the outdoor antenna and good co-ax. However, a simple vertical dipole would work as well, if not better, than an expensive discone, which is trying to be a "jack of all trades".
Solid State Electronics in line notch filter. Just goes between the antenna and the antenna input on the scanner. You are then able to "notch" the powerful FM broadbast band (or any other one causing problems) out. Worked very, very well.