[App_rpt-users] Fwd: COR signal getting confused

Fri Sep 26 22:05:03 UTC 2014

Mike,

 Are you using PL or noise squelch or both? Like I said I have not seen this problem and I am using basically stock timing. Every time the PL or squelch goes untrue for a certain (short) duration you should hear a courtesy tone. Perhpas you should try duplex=0 just to see if there is an issue with TX recovery.  Do you have another radio you can try?  
73 Doug
WA3DSP
http://www.crompton.com/hamradio

From: kf7mbk at w7ara.net
Date: Fri, 26 Sep 2014 10:18:19 -0700
Subject: Re: [App_rpt-users] Fwd: COR signal getting confused
To: doug at crompton.com
CC: app_rpt-users at ohnosec.org

The scope image in the OP shows there doesn't appear to be a problem with pulling hi or low,  The transitions (without the RC) are very clean and go all the way to ground..  It seems like the URI is doing edge detection instead of level detection, and it's just missing fast edges.  Wasn't sure if this was something that could be tweaked in software or if I'll have to put some external debounce logic on the line.

On Fri, Sep 26, 2014 at 10:07 AM, Doug Crompton <doug at crompton.com> wrote:

Mike,

 Before you change any timing make sure as Jon pointed out that your COS signal is going hard high and low on signal and non-signal. You might need a pullup. The URI is kind of weak in that regard.  It should be TTL levels  <.5 volt low and >2.5 volt high and preferably rail to rail.

73 Doug
WA3DSP
http://www.crompton.com/hamradio

From: kf7mbk at w7ara.net
Date: Fri, 26 Sep 2014 09:56:21 -0700
Subject: Re: [App_rpt-users] Fwd: COR signal getting confused
To: doug at crompton.com
CC: app_rpt-users at ohnosec.org

Doug,
First: thanks for the excellent writeup on getting allstar running on the BBB.  I used it to get up and running very quickly and is the setup I am having this issue with.
I am running duplex =1 as well.  I have not changed any timing values, (I'm essentially running the as-installed setup from the install image on your site) but I will take a look at them and see if I can make some changes for the better.
Thanks!-Mike

On Fri, Sep 26, 2014 at 9:49 AM, Doug Crompton <doug at crompton.com> wrote:

From: doug at crompton.com
To: kf7mbk at w7ara.net
Subject: RE: [App_rpt-users] Fwd: COR signal getting confused
Date: Fri, 26 Sep 2014 12:46:14 -0400

That is very strange. Have you changed any of the default timing values? Are you using simplex/duplex? Courtesy tone? Timing values could effect that. 

I use simplex with courtesy tone (duplex=1 in rpt.conf)  on several nodes and I have never seen that problem. I have one user who has a signal like you describe. He walks in a park with a handheld and he is often in and out.

Also I assume you are not using any rxdelay?

73 Doug
WA3DSP
http://www.crompton.com/hamradio

From: kf7mbk at w7ara.net
Date: Fri, 26 Sep 2014 08:50:51 -0700
To: app_rpt-users at ohnosec.org
Subject: [App_rpt-users] Fwd: COR signal getting confused

Resending since my initial post has been pending moderation for 2 days now and got no reply from the list owner email.

I have modified an HT to bring out the receive LED signal and use it

as the COR input to a DMK URI. It is a digital signal as viewed on a

scope (i.e. very short slope in the transitions)  This seems like it

would work well and it does on strong signals. But on marginal signals

where the LED may blink on and off quickly (like during picket

fencing), it seems to confuse the URI (or the software) were it will

start off good, but then a quick dropout of the COR signal will cause

the software to no longer detect carrier, even though the signal on

the COR input has been restored.  Even if the input is solid high (or

low in my case, I'm using usbinvert) it will not detect a carrier

until there is another dropout of adequate time to "reset" it.

I've tried putting a simple RC on the input but it didn't really help

much.  Seems the URI (or software) needs a significant minimum time

between transitions to properly detect them, long enough that it would

delay the carrier detection too much without a circuit more complex

than an RC (i.e. something that would allow instant keyup, but delay

the key down.)

Linked is a scope image. 
https://lh5.googleusercontent.com/-CsJ9autUTAE/VCWK-uNJJpI/AAAAAAAAPSM/VsVvbPVvuEA/s800/20140923_184107.jpg
Carrier was detected until this signal

dropout event.  Ch A is my RC filtered signal sent to the URI, Ch B is

the signal out of the radio.  Carrier was not detected after the 5th

dropout even though the signal remained low.

Anyone ever experience this and/or have ideas on how to fix it?

Thanks.

Mike

KF7MBK

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