[App_rpt-users] Fwd: COR signal getting confused

[Mike M]

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 DougWA3DSPhttp://www.crompton.com/hamradio
> <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 DougWA3DSPhttp://www.crompton.com/hamradio
> <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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