Visit our newest sister site!
Hundreds of free aircraft flight manuals
Civilian • Historical • Military • Declassified • FREE!

TUCoPS :: Radio :: ic2at_4.txt

Icom 2A/3A/O2AT mods


Connecting Icom 2AT to packet. Jim Gerritz WA4FMA

The Icom 2at HT is an excellent little rig to operate packet. It features usual
fast electronic switching between transmit and recieve as well as a reciever
that comes back imediatly after a transmission without delay. A slow recovering
reciever can be a real hinderince to packet operation. The best feature is that
the Icom 2at is one of the most ecmonimical fully synthesized of the HT on the
market today. Like many of us, it is my only full coverage 2mtr rig. Following
it with the Heath 15 watt amp gives it the power of many larger radios. A must
for packet.
The only problem is that it has no seperate PTT line. Any time the resitance of
the center pin of the outboard mike jack is lowered, the transmitter keys. This
is the difficulty with packet. What follows is a simple schematic showing how
to connect the 2at to the TNC ustilizing a simple inexpensive audio output

.       --------) (---------- (To Center pin of 
.               ) (             Icom mike jack)
.      600 ohm  ) (  8 ohm
.  To TNC out   ) ( To Icom 2at mike jack
.               ) (
.       --------) (--------- (To PTT line of TNC)                

If there is a center tap on the transformer, this may be clipped off as it is 
not used in this application. The speaker jack of the Icom 2at is connected as
per instructions provided with the TNC.
For best results, I have found that if the volume control of the HT is between 
the 9 and 11 O'clock positions, good copy should result. I am using the MFJ 
1270 TNC.

73 and Happy packeting!
Downloaded from packet BBS.  

Call the HAM HOTLINE in Boston (voice) 617-437-0111
the ARRL Eastern Mass Public Information Office

TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2015 AOH