[arm-allstar] PTT Delay idea

[David McGough]

Okay....I think this board (or a similar one) will solve your ALC issues.  
I haven't measured the actual dynamics of this board, with the supplied
component values.  These values could be adjusted to allow wide
modification of all the various parameters, or course.  I would guess the
attack is under 1mS and release maybe 100mS. I know on a radioless node,
with a electret mic attached and without this board, you can easily
pop-your-P's, even with the levels set low. With this board, no spattering
at all!!!

Here is a datasheet for the SSM2167 chip:

https://www.analog.com/media/en/technical-documentation/data-sheets/ssm2167.pdf


73, David KB4FXC




On Tue, 5 Mar 2019 john at qso.com wrote:

> I'll look into that. Thank you. Right now I have one of those old cassette tape recorders in record mode / monitor mode. 
> What's the recovery time in the ebay unit?  I see adjustments for the 
other vectors.  Also as far as what Doug mentioned, I think I'll wait for 
that, although another board project seems inviting.  I'm using ALC on 
the transmitter because my finger is always on the volume control turning 
people up and down.  Why not? It's my repeater after all 😊
> 
> To answer an earlier question, I have a URI connected to a Motorola 
Quantar powered by a Pi from Doug's image.
> 
> 
> -----Original Message-----
> 
> John,
> 
> Have a look at this nifty little compressor/limiter board. I'm using 
them now for solving mic audio issues and they work GREAT!
> 
> They should work just as well for RX audio, after adjusting the levels.
> 
> 
> https://www.ebay.com/itm/332468614881
> 
> 
> 
> 73, David KB4FXC
> 
> 
> 
> 
> On Tue, 5 Mar 2019, "John Griffith via ARM-allstar" wrote:
> 
> > Well then that answers that. I can wait. Thank you. 
> > 
> > Right now, my wife's voice on the ID'er is over deviated the first 200 
> > ms as my leveler's attack time is slow, But at the same time recovery 
> > is slow so that normal conversation afterwards doesn't sound 
> > compressed like a commercial broadcast AM radio signal does.
> > 
> > The network I'm on encourages people to hold the mike key down a full 
> > second before they talk so that all the entire network can key in 
> > order not to cut off their first words. It's an issue.  There's 
> > usually plenty of time to knock the leveler down before PTT. Was 
> > wanting to take advantage of that time.  Sounds like your update will 
> > make this moot.
> > 
> > Oh, ALC is automatic level control. 
> > 
> > Again, thank you for all you do.
> > 
> > -----Original Message-----
> > From: ARM-allstar <arm-allstar-bounces at hamvoip.org> On Behalf Of "Doug 
> > Crompton via ARM-allstar"
> > Sent: Tuesday, March 05, 2019 12:00 AM
> > To: ARM Allstar <arm-allstar at hamvoip.org>
> > Cc: Doug Crompton <wa3dsp at gmail.com>
> > Subject: Re: [arm-allstar] PTT Delay idea
> > 
> > John,
> > 
> >  I think you contradict yourself because you want audio to level 
> > before PTT but you tell people to hold PTT for a few seconds before 
> > they talk. That does not make sense. Then there would be carrier 
> > without audio. What is this ALC? A good audio limiter/compressor 
> > should be almost instantaneous in response. Are your levels really 
> > that wacky? Perhaps the users need to set their levels better! You 
> > could delay PTT any amount you want with a rather simple circuit but 
> > remember you are cutting off the beginning of the transmission by that amount.
> > 
> > On a side note we will be introducing a new channel driver later this 
> > year that will allow you to use a SW limiter/compressor with custom settings.
> > 
> > 
> > *73 Doug*
> > 
> > *WA3DSP*
> > 
> > *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
> > 
> > On Mon, Mar 4, 2019 at 7:50 PM "John Griffith via ARM-allstar" < 
> > arm-allstar at hamvoip.org> wrote:
> > 
> > > I was wondering if there's a way to delay PTT for 200 milliseconds 
> > > (but
> > not
> > > the audio stream) so that my ALC can properly level out before 
> > > anything
> > is
> > > heard on the repeater?  The people on the repeater network I'm on 
> > > are pretty good about holding the key down for a second or 2 before 
> > > talking, so it would be a big deal.
> > >
> > > Another option I was thinking about would to have a tone or white 
> > > noise
> > or
> > > anything really.. keep the ALC circuit busy and leveled during times 
> > > of non-transmit.  Anyone have an idea?  I already have a burst of 
> > > noise at
> > the
> > > very beginning of the repeater ID, I would just want that to be 
> > > during
> > the
> > > 200ms.
> > >
> > > John
> > > N7OKN
> > >
> > > _______________________________________________
> > >
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> > > ARM-allstar at hamvoip.org
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> > >
> > > Visit the BBB and RPi2/3 web page - http://hamvoip.org
> > >
> > _______________________________________________
> > 
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> > 
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> > 
> > _______________________________________________
> > 
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> > 
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> > 
> 
> 
>