[ARDF] My PicCon "script"

Tue Oct 25 17:17:46 PDT 2005

Hi Ken,

I was assuming that you had a receiver connected to each PicCon, and the
receiver would hear anything transmitted on its set frequency. If so,
then you could use another transmitter to transmit a DTMF "1" and that
would start everything all at once.

When I program the PicCons, I have DTMF 1 - 5 transmit the codes
specific to transmitters 1 - 5 (C codes), DTMF 6 and 7 transmit all the
stuff common to all the transmitters (A1, A2, and A4 codes), and DTMF 0
sets my callsign into the PicCons. I only turn on one transmitter at at
time to program 1 - 5, but have everything on when transmitting
everything else. Clear as mud :)?

Re: MO. It sounds like the red button on my PicCons are what you are
referring to as SW1. Also the "F" that I was referring to is hex and
would probably be the lower right hand button on a 16-button DTMF pad.
It might also be referred to as "D". If you aren't sure, try them all :)
as one of them will most likely do the job.

I just took a look at the schematic for your PicCon and I see it uses a
ceramic resonator instead of a crystal (as you mentioned and I
overlooked.) You can replace the ceramic resonators with a crystal and a
couple of small caps (Byon suggests about 6 pf) which might give you
better long term accuracy. Since I am not an electrical engineer either,
you might email Byon and ask him about this. All of my PicCons uses
crystals. I rather suspect that the crystal will give more temperature
stability than the ceramic resonator but someone else will have to
verify that one :).

Marvin

"Kenneth E. Harker" wrote:
> 
> On Tue, Oct 25, 2005 at 04:06:11PM -0700, Marvin Johnston wrote:
> >
> > Everything you are doing looks good. I have all of that programmed into
> > the Yaesu 470 DTMF memories so I can reprogram all five transmitters in
> > a minute or so.
> >
> > I am assuming that you started them all at once with a DTMF "1" after
> > they were deployed in the field. The only problem with that is some of
> > the transmitters might not be able to "hear" from where you are doing
> > the start. Setting the A4 start delay allows them to be started before
> > they get deployed, and eliminates that problem.
> 
> Actually, I held all five of the them in one hand and hit the SW1 on each
> in rapid sequence (takes about a half second.)
> 
> > FYI, undocumented on the earlier PicCons (not sure about the latest
> > revision), DTMF DF while holding the red button down will set the PicCon
> > to transmit MO for the finish beacon.
> 
> I don't understand this.  I don't have a red button and I don't think
> there's an "F" on my DTMF keypad.
> 
> > 30 seconds sounds rather excessive but the drift has nothing to do with
> > setup, but rather with the crystal clock frequency for the PicCon. You
> > can trim the frequency down by putting some capacitors from each side of
> > the crystal to ground. The PicCons I used drifted perhaps 3 or 4 seconds
> > at the end of about 6 hours. I need about 22 pF on each side of the
> > crystal used in the Microhunt transmitters to get the timing close. I
> > would guess that you could probably set the audio to some frequency at a
> > *VERY* slow CW rate transmitting Dahs, and use a frequency counter to
> > get close to the proper frequency without having to wait several hours
> > to find out the drift.
> 
> I'll check into this.  I have the current model of PicCons, in the
> translucent green cases.  The ceramic resonator Y1 has three connections
> to the PC board (let's call them left, middle, and right.)  Do I put a cap
> in line between left and its pad on the PC board, and then do the same with
> right?  Or do I leave the resonator in place and put the cap between left
> and ground and between right and ground?  (I'm not really an engineer, if
> you couldn't tell :-)  Aside from painful experimentation, how would I know
> what value cap to use?
> 
> Does temperature have anything to do with it?  Between the time I set out the
> transmitters and when we picked them up, the air temperature had gone
> up like 20 degrees Fahrenheit.
> 
> Some of the PicCons had drifted well over 60 seconds off their cycle over
> a period of 7 hours.
> 
> > Marvin, KE6HTS
> >
> >
> >
> > "Kenneth E. Harker" wrote:
> > >
> > >      This is the script I used to program each of the PicCons at the Texas
> > > ARDF Championship last weekend (where several of the transmitters gradually
> > > drifted in time during the course of the event, leading to significant
> > > overlaps.)  This specific example is for MOH.  I'd appreciate feedback from
> > > the more savvy PicCon users if there is anything I'm doing wrong:
> > >
> > > C123133518#  Set Morse code ID to WM5R
> > > A10100       Set a transmission delay of one minute duration
> > > A20056       Morse code sequence is 56 seconds long (leaving 4 seconds for ID)
> > > A30500       Transmission loop time is 5 minutes
> > > A40000       No initial delay time
> > > A50000       Run until commanded to stop
> > > B188         Set Morse code sequence to default code speed
> > > B220         Set Morse code ID to 20 WPM
> > > B371         Set Morse code tone to ~700 Hz
> > > D4           While holding down button, set IARU transmitter ID to MOH
> > > C411123#     Set transmission sequence order beginning with three delays
> > >
> > > Start with SW1
> > >
> > >      Anything obvious that I was doing wrong?  For at least the first several
> > > cycles, everything sounded like it was in proper timing and sequence, but
> > > by the time of the first start three hours later, some of the transmitters
> > > had drifted by as much as 30 seconds.
> > >
> > > --
> > > Kenneth E. Harker WM5R
> > > kenharker at kenharker.com
> > > http://www.kenharker.com/
> > >
> > > _______________________________________________
> > > ARDF mailing list
> > > ARDF at kkn.net
> > > http://www.kkn.net/mailman/listinfo/ardf
> 
> --
> Kenneth E. Harker WM5R
> kenharker at kenharker.com
> http://www.kenharker.com/