[arm-allstar] Receiver audio levels

[Doug Crompton]

Cole,

 Typically you want about 100mv p-p or so max but you can turn off rxboost in simpleusb.conf  - rxboost=0   

It defaults at 1 or on. That might get you in the ball park but it looks like you do need to drop the level down a bit also. I would suggest a 47 K in series with a 10K to ground on the FOB side for starters. Then take the 47K up if it is still too high. Experiment until you can get the level value reasonably close to mid scale (500). 
73 Doug
WA3DSP
http://www.crompton.com/hamradio


From: colecaz at gmail.com
To: arm-allstar at hamvoip.org
Date: Tue, 3 Mar 2015 16:12:45 -0700
Subject: [arm-allstar] Receiver audio levels

I’m having trouble setting the receive audio input level to interface with a Motorola Radius radio. I’m using a USB FOB modified as shown on http://www.crompton.com/hamradio/usb_fob_modification/ , and connecting to the audio output of the radio on the rear connector I am unable to set the proper level using simpleusb-tune-menu.  Even going all the way to 0 isn’t enough.  The peak to peak voltage out of the radio with 1kHz audio/3 kHz deviation is 1.2 volts.  I have confirmed that it is truly sensing the audio by shutting the modulation off and seeing the tune indicator line go to about 500 Hz of noise. What audio level directly into the FOB, after the voltage divider shown in the mod, is correct for decent tuning range? Cole CunninghamAA7RD
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