ATCS Monitoring using Maxtrac radios

[Josh]

I read that the MaxTrac800 can be modified to operate RX on the 902 ham frequencies... since this is so, the radio should also be able to RX on the 896 and 897MCP frequencies, and I did the mods which proved it so.

Everything went well, I can audibly hear the MCPs and they sound fine.

So, I went ahead and hooked it up to my computer via sound card, using pins 11 (flat RX audio) (yes JU551 is set to position A) and pin 7 (ground) of the 16 pin rear connector to interface to my computer's line-in.

The audio levels look good on the ATCS Monitor signal analyzer, but the program will not decode any ATCS packets, it errors all of them out showing "FEC error". with FEC correction disabled, I get Frame header checksum errors.

I have no idea why when my setup with a scanner is exactly the same. I am only a couple miles from a few different MCPs and can monitor them all day long with the scanner (Radio Shack PRO-2005).

RX specs for this out-of-band radio are still good, according to, again repeater-builder.com so I don't know what gives.

Anyone else have helpful input for decoding data on a maxtrac successfully?