[aprssig] d700 in mic-e mode

Wes Johnston aprs at kd4rdb.com
Fri Feb 18 21:35:41 CST 2005

Sure, our controller runs everything thru a db25 connector.  I got one of those
DB25 breakout boxes from radio shack and mounted a de-9 on the side of it.  I
jumped all the lines from one db25 to the other, except for the COR line into
the controller.  This is jumped with a 1k resistor.  On the controller side of
the 1k resistor, I connect it to de-9 pin 8.  RX audio and ground also need to
be connnected to de9 pins 5 and 6.

The tnc is a kpc3plus with CTRL A MUTE 1.  The programs the CTRL A line to
mirror the CD LED and 10mS bounce time.

When the TNC hears a carrier, it asserts the CTRL A (de-9 pin 8) to ground. 
Since this is connected to the COR line, the repeater controller thinks the
carrier has dropped and mutes the packet for you.  The 1k resistor serves as a
current limiter to protect the radio, which is trying to raise COR high.

If your COR is active low, you'll need to use a PNP transistor and a couple of
extra resistors in addition to what I've descibed above.  OR you can get a
normally closed reed relay from mouser.

We also had to build a Y cable that splits out the TNC TX and PTT lines to the
APRS radio, and the TNC RX and MUTE lines to the repeater controller.


Quoting William McKeehan <mckeehan at mckeehan.homeip.net>:

> Can you give some details on how you setup the repeater to mute the packet
> burst?
> On Fri, February 18, 2005 4:32 pm, Wes Johnston said:
> > And now for something completely different!
> >
> > We finally got one of our repeaters setup for MIC-e and muting the packet
> > burst.
> >  Packets are gated over to 440 (since the repeater is so close in frequency
> to
> > 144.39), and at the main IGATE site, we digipeat the 440 packets back onto
> 2m.
> >
> > Has anyone ever noticed when using the d700 in PTT mode (ie mic-encoder
> mode)
> > that the radio doesn't always send a posit right as you unkey?  It will
> send a
> > position about 1 to 2 seconds later every once in a while.   I thought at
> > first
> > it was hearing some packets on 144.39 just as I unkeyed, and that was
> causing
> > it
> > to hold off, so as an experiment, I unkeyed with the squelch turned down
> all
> > the
> > way on the data side of the radio and that did not cause it to hold off
> tx...
> > could it be that the radio is processing a packet or sending a waypoint to
> the
> > GPS at the moment I unkey and that's the holdup?
> >
> > Sure is aggrivating... since when it doesn't TX right away when I unkey, it
> > will
> > TX 2 seconds later when the other party I'm talking to has just started
> > talking
> > and it blanks him out for a second or so.
> >
> > Wes
> >
> > _______________________________________________
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> >
> >
> --
> William McKeehan
> Internet: mckeehan at mckeehan.homeip.net
> http://mckeehan.homeip.net
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