[INRAD] Icom band decoders

[Joe Subich, K4IK]

Kirk, 

---- Original message ----
> Date: Fri, 27 May 2005 17:09:25 -0500
> From: K4RO Kirk Pickering <k4ro at k4ro.net>  
> Subject: [INRAD] Icom band decoders  
> To: Inrad List <list at inrad.net>
>
> I've been trying to send this to George and Dave directly,
> but there seems to be some kind of problem with an anti-
> spam filter rejecting my domain.
>
> I am having two different problems with Top Ten band 
> decoders.
>
> The first problem is that they will not consistently engage
> the 160m meter position when decoding an older Icom radio. 
> I have encountered this before with other Icom rigs, and it 
> had to do with the decoder's break point between 80 and 160 
> being too close to the cross-over point of the analog band 
> voltage coming from the rig.  At one time I added a small 
> battery in series with the band-voltage line to the decoder 
> to bump it up by 0.5 volts. 

The TopTen manual for the Icom Band Decoder see: 
http://www.qth.com/topten/bd-iman.pdf indicates there 
is a resistor soldered in parallel with R1 (page 4 - 
Modifications Required for Use With IC-775DSP). Removing 
it will lower the threshold voltages slightly.  It may help 
your situation. 

73, 

   ... Joe, K4IK