Temp 900xtal filters to test 800 maxtrac receivers

PETNRDX · Post by **PETNRDX** » Fri Nov 07, 2003 12:48 pm

I was wanting to check a pile of 800 maxtracs to verify that they work at 902 (and pick the best ones) before converting them as repeater receivers. I don't have enuf 915 filters, and I don't want to go to the trouble to solder them in just to find that one receiver is better than another. So I looked a the difference in the 915 and 860 Xtal filters. I peeled the top of the label of and it appears that physically the 860 filter has two more holes in it. Just as a test I made small "horseshoes: of 12 ga solid copper (house) wire and inserted them, while generating a signal into the radio. By sliding these horseshoes up and down I was able to get the radios sensitivity down to about -110 dB (appx .7 microvolt). This may be a good (fast) simple test to verify that the rf board works at 902 and to pick the "best" boards for final complete conversion. Anybody have any comment on this? It was way easier than removing the board and jumpering the bottom of the filters.

Max-trac · Post by **Max-trac** » Fri Nov 07, 2003 1:09 pm

Pulling the board is easy. Pulling the filters is a pain. But that is what I did and just put a jumper with excellent results.
(I have a full set of celwave bpbr duplexer to protect the rx)

If you leave the filter in and just jumper it, won't the filter still have some effect??

PETNRDX · Post by **PETNRDX** » Sat Nov 08, 2003 10:00 am

I know pulling the boards is pretty easy, I just had a problem with the rx I was going to use for a repeater. It quit unmuting, and in frustration I just wanted a fast way to really completly check the radios for all functions, and choose the best ones (I have a pile of them).