Batboard

I had a need for a high quality receiver to listen to the input side of the 800 band for interference hunting, and other trouble shooting. Having shoved a few other radios outside their intended spectrum on other bands, I decided to give it a try. Low and behold, I was successful, and ended up with rated performance across the entire 800 input band.

So, I have a couple of questions... Has anyone else done this before, and if so, I'm curious how you accomplished it. If not, is there any interest in seeing a writeup? I'll probably do a couple for the other guys in the shop, so I could carefully document the process... that is, if anyone else is actually interested.

I would be interested in reading about your project.

Anyone who maintains an 800 system can use a receiver that listens to the input side.

It is a great tool for looking for interference, particulalrly in the latest systems where the base stations are all digital - you may get an "illegal carrier" report out of that STR or GTR but what was the actual signal?

One other way to create such a receiver is to use a Desktrac repeater receiver - or modify a Maxtrac if you can find suitable front end filters, but since 800 analog Spectras are plentiful, a mod for those would be great.

Well, I'll go ahead and write something up about it. I'm going to do another one this weekend, so I'll document the process. BTW, the process is identical to move a 900 Spectra receiver down to 902. Basically, it involves adding 1pf chip caps to the filter, then retrimming with a Dremmel to bring it back up, and making the LO microstrip about 30% longer.