Re: [TSCM-L] {3715} Spectrum Inventory Proposal

From: James M. Atkinson <jm..._at_tscm.com>
Date: Thu, 28 May 2009 08:31:55 -0400

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Date: Tue, 21 Aug 2007 15:17:47 -0500
Subject: Re: [TSCM-L] {1864} Re: Low power devices - Fox Hunts
From: James Greenwold <b..._at_charter.net>
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I used the same type of transmitter for bumper beeper tracking. We placed a
130dB 6 attenuator in the antenna and as we got closer just switched on more
dBs. Worked fine
-- 
Thank you for your time
James Greenwold
Bureau Of Technical Services
715-726-1400 
b..._at_tacticalsurveillance.com
> From: kondrak <kon..._at_phreaker.net>
> Reply-To: TSCM-..._at_googlegroups.com
> Date: Mon, 20 Aug 2007 20:14:57 -0400
> To: TSCM-..._at_googlegroups.com
> Subject: [TSCM-L] {1864} Re: Low power devices - Fox Hunts
> 
> 
> We did one, where we initially beaconed for 15 minutes with 100 watts, a
> county away from the starting point.
> After 15 minutes, we dropped to 30 watts, for 20 minutes, then 5 watts,
> and finally down to 100 mw. We didn't go any further down in power,
> because the fox was located in a 1 gallon bleach bottle, under a dock on
> the riverside.
> The interesting thing is most hunters are not prepared for too much
> signal. Without attenuation, you cant make reliable fixes due to
> multi-path. I designed a signal detector, that gave an audio output
> based on signal strength, with 80db of attenuation, all switchable in 1
> db increments. Yes those were fun days....
> Yes its amazing how the fun things we did play into more practical
> skills now...
> 
> James M. Atkinson wrote:
>> Since I grew up in a Coastal New England community I used to go on
>> Fox Hunts in the White Mountains, in the Osippee area, and around
>> Mount Desert Island. Didn't really care for hunting around the lakes
>> and marshes, and likes the mountains and coastline better.
>> 
>> The ones I enjoyed the most involved an unknown frequency, unknown
>> locations, but a quasi unknown time transmitting where it chirped, so
>> the first thing you had to do is figure out the timing duration and
>> frequency before you could do anything else. Then it was
>> rush-like-hell to a second location to capture a second chirp to DF
>> to get a little closer, and then spiral in on the fox.
>> 
>> I also liked the ones where we started 10 miles away from the fox,
>> but each time the fox transmitted the power levels dropped so you had
>> to move fast because you only had a 4 hour window or less before the
>> fox died as the power level dropped to the noise floor.
>> 
>> The ones that started on an HF frequency where loads of fun where a
>> helium balloon was used to hold up a long wire antenna for the first
>> hour, then the balloon would get released, and the fox switched to a
>> different transmitter, on a different frequency, and then an hours
>> later another switch, and so on.
>> 
>> The losers bought dinner and/or movies for the winners, and the
>> winners got to help the hunt masters (or game warden is you will)
>> plant the next fox.
>> 
>> I never had any interest in the building and planting the fox, but
>> enjoyed the hunt more then anything else, especially when it you
>> could not use radios for communications and had to sneak up on the
>> fox from some distance away.
>> 
>> I don't recall any of the foxes being more then a couple of Watts,
>> and recall that the best ones would drop below 100 mW by the time the
>> hunters got within a mile, and under 10 mW within a quarter mile.
>> 
>> -jma
> 
> 
> > 
Received on Sat Mar 02 2024 - 00:57:19 CST

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