[App_rpt-users] DSP/BEW question

[Tom Caspar]

I was able to get the squelch to calibrate by adding JP1 as you suggested. Now The RSSI will evaluate correctly as long as it is just the carrier and no audio present.   It does not hold a value when there is audio present.  Additionally even a full quieting signal will show RSSI's in the 70-120 range during periods of voice content, almost opposite the desired effect.

Is there anything else I might be able to try with this?

Thanks,
Tom


-----Original Message-----
From: Tim Sawyer [mailto:tim.sawyer at mac.com] 
Sent: Friday, April 03, 2015 11:18 AM
To: Tom Caspar
Cc: app_rpt-users at ohnosec.org
Subject: Re: [App_rpt-users] DSP/BEW question

Even with a 4kHz roll of you should be able to get SOME squelch action. Something else is wrong. You have to get the squelch to calibrate and BEW won’t help with that. BEW stands for Bandwidth Elimination Window. It blocks voice peaks from falseing the squelch off.

If the squelch won’t calibrate perhaps the discriminator output is low. In that case add JP1 for some gain to the noise amp. 

The difference between BEW 1 and 2 is that 2 is a more aggressive action. 
 
> On Apr 2, 2015, at 4:49 AM, Tom Caspar <tom.caspar at cpcomms.com> wrote:
> 
> A while back it was suggested that I try using the DSP/BEW firmware to get my RTCM's working with some DMR radios that I'd like to use as receivers.  Even when in analog mode the radios audio spectral content rolls off at 4khz.  Unfortunately this still didn't help, RSSI is always evaluated as 255.
> 
> Since I couldn't find any additional documentation on this feature, a couple questions.
> Whats the difference between DSP/BEW mode 1, and mode 2 in the RTCM's configuration screen?
> Are there any other parameters that might be relevant to this feature?
> Is there any difference between running the voter_smt firmware and the voter_dspbew-smt firmware with DSP/BEW set to 0?
> 
> FWIW I was able to successfully use both DSP/BEW modes 1 and 2 with a traditional analog radio.
> 
> Thanks,
> Tom
> 
> 
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