Thanks Mike, for drawing this up, for clarity the orange wire is the one that should be held low to allow the steady tone output - if cycled it will create the reverse burst that can be detected by an unknown group of radios. And just like a fan delay or a ptt delay you could add a cap to the cor signal but that won't help the discriminator detect fluttering mobiles, that is a discussion for another day. I have used 10, 15 and 20k resistors to make this circuit that Mike has drawn, if the FET can switch quicker than a NPN then use it - that answer may require a degree in advanced silicon applications, the NPN has run for about 7 years near Lake Erie but your mileage will vary and surely be shortened if sparks fall from the sky.
Mike Morris WA6ILQ wrote: > > It's not that hard... > Unfortunately I don't have a working test bench right now to do any > engineering. If somebody wants to run with the idea below and do > the breadboarding and write up the article I'd be glad to edit it, > HTML-it, and post it. > > Basically you leave the encoder running all the time (Virden, it that > what the orange wire you were referring to does?), and have two > resistors in series between the encoder output and the TX modulator > input. A FET goes from the center point to ground. You control the > FET with the RX COR so that the encoder audio is pinched off when > the RX squelch is closed. > > You can also use an ordinary NPN transistor in a pinch. > > You'll need Courier font for the diagram below. > > encoder > output --\/\/\/--+---\/\/\/\/---- to TX modulator (usually > ! the top of the dev pot (may > ! need a DC blocking capacitor) > ! > +--! > !<---\/\/\/---to controller output > +--! or COR output > ! > gnd > > Personally, I'd not use the raw COR output - I'd add a little delay > somewhere in the system so that a fluttery signal didn't flutter the > PL encoder on and off.... Maybe use and RC network, or set up a > logic output on the repeater controller with a 1/3 to 1/2 second delay > > and control the FET with it, and have a 2 to 3 second carrier delay > (hang-in) timer on the repeater. > > End of problem. > > By the way, this trick has been around for 30 or so years - I first > did it on > WA6EWS's Mocom 35 to allow the PL encoder to be enabled or disabled - > Moto > had a T-filter using two resistors like the diagram above with a > capacitor to > ground... I used the front panel "extender" switch to short out the > cap and disable > the tone. > > Mike WA6ILQ > > At 01:16 PM 12/20/03 -0600, JOHN MACKEY <[EMAIL PROTECTED]> wrote: > > > Yes, that would be very good for a write up! > > > > "Chuck Kelsey" <[EMAIL PROTECTED]> wrote: > > > > > Why don't you write it up in some detail and submit to Kevin for > > > posting on the Repeater-Builder web site? > > > > > > Chuck > > > WB2EDV > > > > > > > > > ----- Original Message ----- > > > From: "Virden Clark Beckman" <[EMAIL PROTECTED]> > > > To: <[email protected]> > > > Sent: Saturday, December 20, 2003 8:19 AM > > > Subject: Re: [Repeater-Builder] TS-64 > > > > > > > This is defeatable, I have described this several times - > > instead of > > > > turning off the tone generator thereby activating the reverse > > burst just > > > > use a hold low in between 2 15K resistors to pinch the pl output > > of the > > > > ts64 module going towards the modulator. To use this you will > > have to > > > > hold the orange wire low full time, and you will find the > > switching time > > > > is faster than the reverse burst. > > --------------------------------------------------------------- > Yahoo! Groups Links > > * To visit your group on the web, go to: > http://groups.yahoo.com/group/Repeater-Builder/ > > * To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service. -- 73...Clark Beckman N8PZD Pursuant to U.S. Code, title 47, Chapter 5, Subchapter II, �227, "Any and all nonsolicited commercial E-mail sent to this address is subject to a download and archival fee of $500.00 U.S.". E-mailing denotes acceptance of these terms. Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
