[App_rpt-users] [Bulk] Issue with Hangup after first keying

Ed Wilhelm vacuumtubesforever at gmail.com
Wed Jul 3 21:40:12 EDT 2013

The Icom IC-A110 is an AM aircraft radio. Being AM there is no 
discriminator audio, and DSP derived COR won't work due to the nature of 
the AM signal. You're going to have to dig around in the squelch circuit 
to find a point that toggles. Most AM type squelch are usually derived 
from the AGC. Don't what they're doing in the Icom.

Ed, W8VT
Nodes 27849 29496
Beckley WV

On 07/03/2013 07:37 PM, Joshua Hintze wrote:
> Thank you for all the suggestions thus far.
> I'm using an ICOM IC-A110 VHF radio. I was able to find some
> schematics/block diagrams in the service manual here:
> http://elektrotanya.com/icom_ic-a110,_a110e_service_manual.pdf/download.html
> This is my first time trying to dig through a radio and find a COR. I'm not
> sure either where to get a discriminator audio signal either.
> Josh
> -----Original Message-----
> From: Bryan D. Boyle [mailto:bdboyle at bdboyle.com]
> Sent: Wednesday, July 03, 2013 3:29 PM
> To: Joshua Hintze
> Subject: Re: [App_rpt-users] [Bulk] Issue with Hangup after first keying
> On 7/3/2013 4:48 PM, Joshua Hintze wrote:
>> Thanks Ben for the quick feedback. I think I might have figured it out. It
> turns out my COR signal might not necessarily be the best COR signal. It
> looks like the signal goes high on BOTH RX and TX. This is probably causing
> asterisk to think its receiving when its sending getting into a nice
> infinite loop.
> Then you don't have a true COR signal.  What radio (make/model) are you
> using?  Can you get discriminator audio??  If so, you can use dsp to
> derive COR; otherwise, you need to look elsewhere.  Sounds like you're
> too far down the circuit.
>> I'm going to try an AND gate with the PTT so that PTT has to be high (i.e.
> NOT TX) and speaker mute (my COR) has to be high for a true COR output on
> RX.
> Sounds complicated; I'm thinking some quality time with the schematic
> will provide an answer that is more agreeable and doesn't require
> building logic circuits.  In all the machines I've built the most
> complex interface has been a pullup resistor on the DB25 connector.  And
> that's for everything from a micor to wouxun HTs to maxtracs and gtx's
> and systel, and ALinco radio-based repeaters.  And throw in a couple GE
> rigs (Mastr-IIs) along the way.  Heck, I even interfaced a TR-33C as a
> receiver in a pinch.
>> In the meantime I tried carrierfrom=vox but it didn't really seem to work.
> Anybody get this working properly?
> As our Maximum Leader Jim says: "Friends don't let friends use VOX".
> Not a way to do it; and is an artifact of development.
> Allstar 27294, 27295, 27673, 27710, etc.
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