[aprssig] Radio Shack demise - Lets take back 11 meters!
Stephen H. Smith
wa8lmf2 at aol.com
Fri Feb 13 16:25:03 CST 2015
On 2/13/2015 5:01 PM, Robert Bruninga wrote:
> IM thinking simply AM. The only way this can grow exponentially is if it
> is as simple as plugging to the Mic and Speaker.
I tried this once about 20 years ago, in a project to extend TDD
(Telecommuncations Device for the Deaf) normally used over dialup landlines
(basically TTY at 300 baud) to an over-the-air backup. [This was in Los
Angeles just after a major earthquake.]
It was a disaster! Unlike FM, when AM RF gets into the associated computers
and modems, and gets diode-detected, you recover the original modulating audio.
With any antennas nearby (like back-of-the-set or mobile whips), you get a
howling mass of feedback and distortion.
We DID get it to work with AM/FM CB transceivers in the FM mode. These bootleg
Taiwan radios were widely available at swapmeets in the LA area (think the
legendary monthly TRW swapmeet) in the 1980s and early '90s. (I actually
hacked one of these to work on the local 10-meter repeaters.)
Stephen H. Smith wa8lmf (at) aol.com
EchoLink: Node # 14400 [Think bottom of the 2-meter band]
Home Page: http://wa8lmf.net
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