[amsat-bb] Re: Increasing Icom 910H deviation on 9600 setting?
jwcutler at gmail.com
Tue Jan 24 21:35:34 PST 2012
All, for anyone interested, we figured out how to increase the FM deviation
of the Icom 910H. It takes a fairly simple single resistor change to the
rig. A brief overview is online. Thanks to all those who offered comments.
On Fri, Dec 23, 2011 at 11:21 PM, James Cutler <jwcutler at gmail.com> wrote:
> Dear AMSAT,
> Has anyone successfully increased the maximum FM deviation of the 910H
> when using the 9600 setting on the radio? We have not been able to. We
> have two units, and one is maxed at 2.5 KHz and the other at 3.2 KHz
> We've used the service manual to adjust the deviation to max higher values
> (>7KHz). But, this doesn't affect the 9600 input path. Looking through
> the service manual, on page 10-1 lower left corner, it shows that the gain
> control we just set doesn't affect the 9600 path.
> So, I'm thinking of modifying the over modulation detection circuitry to
> allow for a larger peak to peak voltage signal to be input. The components
> that see that voltage appear to be able to handle it.
> Has anyone tried this, or know of another way to increase the deviation?
More information about the AMSAT-BB