[FoxHunt] 2m transmitters required.

Tue Mar 22 00:27:55 EST 2005

I used to sell a kit for a programmable transmitter that used a few simple
commands that I had invented. It included a clock/calendar chip and, over
the years, some rather sophisticated programs were written. Quite often a
number of them would be hidden a week or more in advance. It was always
amusing for the hider to be at the start point along with the hunters and
observe all of his transmitters come up at the proper time.

I recall one hunt when a bunch of transmitters had been programmed to all
sound different, several hours into the hunt they all switched to a
different program (from the same set of programs) so that you were likely to
find yourself hunting a transmitter that you had already found because it
now sounded like one that you had not yet found.

Jim, AF6O

----- Original Message -----
From: "gerald boyd" <wb8wfk at worldnet.att.net>
To: <jsletvol at c2i.net>; "'Radio Direction Finding'"
<foxhunt at mailman.qth.net>
Sent: Monday, March 21, 2005 8:49 PM
Subject: RE: [FoxHunt] 2m transmitters required.

> Jon,
>
> The scripting idea sounds very interesting and would make it a very
flexible
> transmitter. Both I and Mike like that idea. Mike is going to take a look
at it
> to see what it would take to make a system like that. Most likely it would
be a
> basic like language of a few keywords. Will get back with you on what he
finds.
>
> The hardware platform that we designed has a real time clock that runs
when the
> main battery is removed. So some version of delayed start is possible.
Also if
> main battery power is interrupted while its being transported to the field
the
> system will auto recover when power is restored and will stay in sync.
>
> Our plan is to set the clock in our system by plugging in a GPS. When the
> software detects a NEMA data stream it will automatically check the real
time
> clock to see if it needs to be resynchronized with GPS time.
>
> There will be a RS232 commend system where the operator could use a PDA
such as
> an IPAQ or a laptop with a terminal emulator to configure the transmitter.
>
> The operating software will look at who the transmitter is configured to
> (MOE-MO5 or MO) and schedule its transmission based on the real time clock
(The
> first minute of the hour is defined as MOE). There will be no dip switches
as
> all configuration will be via the RS232 port and saved to NV memory.
>
> Our first version will be to get it functional for the championships this
summer
> with ARDF functions, but we are collecting a list of other functions that
would
> be nice for use beyond that event.
>
> For example car type hunts may want a fox that can come on at random times
at
> different power levels each time it comes on.
>
> Where ARDF needs the MOE - MO5 format. Radio -O may want ultra low power
> transmitters. In our design the power level is software controlled on both
HF
> and VHF. Just finished testing the HF pa and was able to very its power.
>
> I noticed that the ARDF transmitters used at the word championships sent a
long
> tone at the end of the cycle. I'm assuming that that's common in Europe.
In the
> US our transmitters have to send the call sign to meet our FCC rules.
That's
> where your scripting idea would be real nice.
>
> 73's
>
> Jerry
>
> -----Original Message-----
> From: foxhunt-bounces at mailman.qth.net
[mailto:foxhunt-bounces at mailman.qth.net]
> On Behalf Of Jon Sletvold
> Sent: Thursday, March 17, 2005 1:24 PM
> To: 'wb8wfk at worldnet.att.net'; 'Radio Direction Finding'
> Subject: SV: [FoxHunt] 2m transmitters required.
>
> Hello, Gerald and Mike
>
> Thanks for a quick answer, and I'm sorry I'm late with an answer. I'll
find it
> interesting to hear about the TX project.
>
> The general foxhunt transmitter has normally only a few options, as
setting
> transmitter cycles and number. I would like a little more sophisticated
> transmitter that could be programmable with some kind of internal
scripting that
> allows the transmitter to alter different modes. The scripting option
allows the
> transmitters to be used with different country specific options without
the need
> to change the firmware.
>
> The different modes of a transmitter could be:
>
> Programming mode: A computer is used to program the transmitters with a
> dedicated program that configures the transmitters correctly. The general
> problem with toggling and push button programming is that the user makes
> mistakes and there are no indications that there are problems until the
> transmitters starts (or don't). A computer-based system would verify that
the
> set-up is correct. A USB or RS-232 connection to a computer is required.
>
> Idle mode, transmitters are in sleep mode waiting to start. A very exact
> oscillator should allow the transmitters to be deployed 24h before the
> competition without an annoying timeslip between the transmitters. This
requires
> a 2 to 3 ppm TCXO oscillator. They are expensive if it's not possible to
find
> mass produced components that could be used.
>
> Transmitting mode are the period when the transmitters are supposed to be
> operating until the competition is over.
>
> A training mode starts with a home beacon that starts 15 min before the
other
> transmitters and countdown to start. The training course could then be
operating
> for a period of time, switch to idle for a defined time and go back to
training
> mode.
>
> "Find me beacon" is an option to collect the transmitters after the
competition.
> This could be short sequence beep that the collector can use instead of
waiting
> 4 minutes before the transmitter starts again.
>
> Cycles should be configurable, also signatures and sending pattern. This
is also
> possible with a internal scripting in the transmitter.
>
> I think this is not an easy task. I don't know the platform you have
designed
> the transmitter on, but a SDR is usually based on a single chip DSP and
could do
> this job as it's not time consuming functionality. The drawback though is
that
> the software must be designed and It's time consuming.
>
> I hope this might have given you some ideas.
>
> 73 de Jon LA9NGA
>
>
>
> -----Opprinnelig melding-----
> Fra: gerald boyd [SMTP:wb8wfk at worldnet.att.net]
> Sendt: 09 March 2005 05:09
> Til: 'Radio Direction Finding'
> Emne: RE: [FoxHunt] 2m transmitters required.
>
> Jon,
>
> Myself and Mike, K5ATM have been working on an DDS based software defined
ARDF
> transmitter.
>
> On march 5th our prototype exciter was demonstrated at the Albuquerque
Amateur
> Radio Club meeting.
>
> This hardware was a functional 2 band ARDF exciter that can generate CW on
80
> meters. On VHF (2 meters) it has the following modulation modes; MCW AM,
keyed
> carrier MCW AM, MCW FM and keyed carrier MCW FM. (MOE,MOI,MOS,MOH,MO5 and
> MO) We
> have also demonstrated other modes such as packet radio data transmission.
>
> It also has a simocast mode for practice sessions (80M and VHF at the same
> time).
>
> Forgoing any development problems we hope to use the transmitters during
the
> Region II ARDF championships this summer. Our event website is
> http://www.ardf.us Registration for the championships just opened this
weekend.
>
>
> We have been sending out progress reports about the transmitter on our two
local
> list servers ABQTHUNT and ABQARDF.
>
> Our project is currently in the advanced stages of development as we have
> demonstrated basic operation with the first generation development
hardware. All
> that is required is to add the power amp stages and final version of the
> operating software and spin the circuit board design.
>
> What additional functions or features would you like to see in an ARDF
> transmitter?
>
> 73's
>
> Jerry WB8WFK
>
> -----Original Message-----
> From: foxhunt-bounces at mailman.qth.net
> [mailto:foxhunt-bounces at mailman.qth.net]
> On Behalf Of Jon Sletvold SICI
> Sent: Tuesday, March 08, 2005 12:58 AM
> To: Radio Direction Finding
> Cc: Mohd-Ayub.Suhaili at shell.com
> Subject: Re: [FoxHunt] 2m transmitters required.
>
> Hello.
>
> I think the only "out of the box" ARDF transmitter available are from
ok2bw.
> There are kits available, but they need to be assembled. Perhaps others on
this
> list can add some information. The products are available from:
> http://www.marecek.sky.cz/
>
> The Norwegian ARDF association is also looking for transmitters, and I've
done
> some research using a microcontroller (PIC or ATMEL), a stable TCXO
> (1ppm) and a DDS to design a 80m ARDF transmitter. The goal is to make
light
> weight transmitters that are fully configurable from a computer (not
online in
> the forest though!) and can be deployed in the field for a week and start
and
> stop at the desired time. This will allow us to have training course that
can be
> operating for several days, but also allow smaller batteries to be used as
the
> transmitters are only operating during the competition time.
>
> What I need is more people to join in with this project in order to share
> working load and reduce the "time to market". It's also a good idea to get
> people with different experience or occupation as HW designers, SW
designers,
> mechanical engineers. I'm my self a HW engineer with a little SW and VHDL
> experience. Are there any one else who might be interested and would join
this
> project?
>
> Regards Jon / la9gna
>
>
>
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