Karl Townsend wrote:

I built a serial port temp. sensor years ago based on this fella's
work:
http://quozl.netrek.org/ts/

And just bought kit 145 from carl's electronics:
http://www.kitsrus.com/pdf/k145.pdf

The unit uses DS1820 temp sensors and connects to the pc serial port.
There is a fifty foot run from the computer to the sensor.

My better half made me quit using it because of AM radio interference.
There is a constant beep beep beep.

I'm once again in need of 24 X 7 temp. logging. Is there an easy way
to salvage this unit? Or am I better off to just start over with some
sort of analog unit?

20 mA current loop, with shielded twisted pair. Maybe RS-485 for that
distance, although I've run cat5 LAN cable 100 feet before.

The secret to minimizing interference to the radio is twisted pair
and shielding. I recommend you get enough conductors so that you can
also use DTR/DSR and RTS/CTS, if only for the sake of completeness.

And again, use twisted pairs and shield the cable. Ground the shield
ONLY at the host end, so that you don't get a mongo ground loop.

Good Luck!
Rich