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[aprssig] HT-220 HT's for APRS

Robert Bruninga bruninga at usna.edu
Fri Jul 20 00:47:42 UTC 2007


> > Has anyone used the old motorola HT-220 HT's for a simple
cheap
> > APRS radio? I found a box full of them in my garage. 
> >
> > I remember doing one years ago, and the only rub was the
lack of
> > a PTT relay.  I think I might just use some diodes and 1/4
wave
> > line this time?
> >   
> Why would it matter if the unit uses mechanical relays or
electronic 
> switching for PTT?

Because it uses the PTT mechanical switch itself to switch the
antenna.  RF goes through the PTT microswitch.  You either have
to put in a relay or devise some form of electronic switch with
PIN diodes and 1/4 wave lines. (as best I remember it)...

Bob, WB4APR

> 
> 
> 
> --
> 
> Stephen H. Smith    wa8lmf (at) aol.com
> EchoLink Node:      14400    [Think bottom of the 2M band]
> Home Page:          http://wa8lmf.com  --OR--
http://wa8lmf.net
> 
> NEW!   World Digipeater Map
>   http://wa8lmf.net/APRSmaps
> 
> JavAPRS Filter Port 14580 Guide
>   http://wa8lmf.net/aprs/JAVaprsFilters.htm
> 
> "APRS 101"  Explanation of APRS Path Selection & Digipeating
>   http://wa8lmf.net/DigiPaths
> 
> Updated "Rev H" APRS            http://wa8lmf.net/aprs
> Symbols Set for UI-View,
> UIpoint and APRSplus:
> 
> 
> 





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