[App_rpt-users] USB URIx overmodulation problem?

[Kevin Custer]

On 3/6/2014 12:17 AM, Kevin Oleniczak wrote:
> I'm using a URIx module with my radio and am in the process of 
> adjusting audio levels. I'm following the well documented procedures 
> to set rx and tx levels but noticed that that choices in txvoice 
> levels have little or no effect. I've made some measurements with my 
> service monitor.
>
> radio tune txvoice 10  >> 0.35Khz deviation
> radio tune txvoice 14  >> 4.8Khz deviation
> radio tune txvoice 15  >> 4.8Khz deviation
> radio tune txvoice 20  >> 5.2Khz deviation
> radio tune txvoice 100  >> 5.2Khz deviation
> radio tune txvoice 500  >> 5.2Khz deviation
> radio tune txvoice 900  >> 5.2Khz deviation
>
> With a goal of 3KHz deviation, its not possible through settings 
> alone. Any ideas why this is so touchy?


It would seem the transmitter audio sensitivity is too great.  Does the 
transmitter have a MIC Gain control?  If so, turn it down.  If not, try 
placing some resistance between the output of the URI and the input to 
the transmitter which will force the URI to output more audio.

Please understand, this control I'm referencing is NOT the deviation 
control.  Many modern transmitters no longer include a MIC Gain pot.

Another thing to try would be to inject audio past some of the 
amplification.  This is not for someone unfamiliar with the radio 
circuitry and full understanding of pre-emphasis and limiting.

What kind of transmitter is it?

Kevin