This is a description of a fox hunt (hidden transmitter direction finding) of May 12-13, 2001 in Honolulu, Hawaii. Included are links to web sites with fox-hunting info and tips.
The map shown below is one team's attempt at plotting the bearings to locate the foxes. They were successful.
Russell's report and other comments follow the map
As the infamous Montgomery Burns would say, "Release the hounds!"
The starting point is the KCC parking lot next to Leahi Hospital. Both foxes are about s5 on my mobile at that location. You do not have to start there if you can pickup the signal somewhere else.
The fox frequency is 147.52 MHz. The foxes are on a 5 minutes cycle. Fox 1 will transmit "MOE" in CW for one minute and then Fox 2 will transmit "MOI" for one minute followed by 3 minutes of silence. For those who don't know CW, just count the "dits". [ E is dit; I is dit-dit ]
The fox will be somewhere between the Kalihi and Kahala Mall and located in a public area. The fox will be a gray ammo can with a 19" whip antenna. It will not be disguised or hidden, but it may be placed in such a way as to minimize attracting unwanted attention.
The fox is running as of now and will be shutdown sometime after 10PM Sunday May 13.
On top of each fox will be a "control code". Write down that code and email it back to me to be placed on the list of winners. (For those reading this via a filtered web page, that email address is "wh7o at arrl.net".
Since there is no start time, there is no "race" Everyone who finds both foxes is a winner. Sorry, no prizes this time, other than the fun and practice.
Please drive carefully and responsibly. If you have a mobile direction finder, you may want to team up so one person drives and the other operates the equipment.
For tips on RDF (Radio Direction Finding) techniques and equipment, check out these links:
A crash course in RDF http://members.aol.com/homingin/equipment.html You may not need anything more then your HT and your body! I've done very well with this simple method.
A good staring point: http://www.homingin.com
A voice of local experience in projects: http://www.qsl.net/kh7o/rdf.html
One popular project is the "tape measure" antenna. Simple construction, and you can find all the parts at Home Depot, build it and still have time to hunt all in one weekend. http://home.att.net/~jleggio/projects/rdf/tape_bm.htm Who says building things has to be hard? But be careful! You might get bit by the homebrewing bug!
Russell Houlton, WH7O, May 2001
This is the map Bev AH6NF and Jim WH6GS plotted to find the 2 foxes.
Red dots, with black lines through them, are locations from which beam headings on the MOI fox were taken (e.g., Punchbowl, Waahila State Park, ST Louis Heights, Kakaako Waterfront Park).
Yellow dots are locations from which beam headings on the MOE fox were taken (e.g.,Waahila State Park, Puu o Kaimuki Park, Triangle Park).
At each location, the direction of the strongest signal was obtained with a beam antenna, a bearing taken with a compass, then plotted on the map.
Black numbers in circles are the order in which the team went to the sites to take readings for each fox.
Equipment used : Icom Z1 handheld, Arrow portable 2M 3 element Yagi, Arrow attenuator, Suunto orienteering compass, map, ruler, protractor, transparent colored dots, red and black marker pens.
The great NFW roundup
From: "Russell Houlton" <R_Houlton@compuserve.com>
Date: Thu, 17 May 2001 00:48:29 -1000
Subject: The great NFW roundup. (Long post!)
What/When: The results of the great National Foxhunt Weekend (Honolulu):
Where: The designated starting point to hear the foxes was Leahi Hospital. Fox MOE was planted across the street from the American Red Cross on Diamond Head Road. (approximately 3/4 of a mile away.) Fox MOI was on King Street just DH (east) of the intersection of King and Keamoku. (About 4 miles away.) Each fox was set to transmit for only one minutes out of every five.
How: This was a "weekend" mobile hunt with the foxes set up at very late Friday night and retrieved late Sunday night. People where free to hunt them any time during the weekend. On top of each fox was a "control code" the successful hunters were to report back to show they had found the fox.
Since there was no official start time, there was no ranking in the finishers.
Who: The following all emailed to say they found both foxes: Rick Ching KH7O & Rod Tom KH7L, Husband and wife team Jim & Bev Yuen WH6GS & AH6NF, and future husband and wife team Todd Kawamoto KH7UK & Crissy Terawaki KH7CHI. The following found only one: Kevin Bogan AH6QO, Dale Fajardo AH7D, and Ralph Toyama NH6PY. I hadn't noticed until just now, teams and only teams found both foxes! I wonder if there is a lesson in there....
A great time was had by all, however tired or sunburned they got. (See details below.)
The foxes where a design called the "Montreal Fox" created by VE2EMM. The fox uses a 18 pin DIP PIC microcontroller to do all the control, timing and audio tones. The rest of the 2.5" square PC board is the small transmitter. The original design claims 0.75W output, but with better transistors, this can be pushed to about 1.5W. MOI was running full power. MOE wasn't doing so well - the problem was discovered only a few hours before placing the fox, so I didn't have a lot of time for troubleshooting. In 48 hours, a fox needs about 4Ah at 12V - so some small sealed batteries were used. If I remember, I'll bring them to the next EARC meeting.
I'd like to thank all that helped in this project:
* KH7O for a battery and the use of his shop. Without Rick's help I would have been fighting to drill all the holes needed for assembly and it would be doubtful that we'd have two foxes.
* AH6QO for the second set of batteries.
* Yvette Lee KH7YY for her assistance and enthusiasm in getting clearance in placing the units. (I'd love to have seen the expression on people's faces when she tried to describe us chaining strange boxes to light poles. No other hobby is quite this strange.)
* And of course Jacques VE2EMM and Henry Schroeder KF6PCE for their long-distance help in making this project fly.
When are we doing this again? Haven't come to that bridge yet. The boxes are built so the hard part is done, but I'd like to find a way to reach more people. While this was short notice, the message doesn't seem to have reached other groups. I'd like to find a better method of reaching everyone before scheduling the next one. Maybe I'll have to get Wayne Jones, NH6K to forward it for me.
Extracts from received email:
KH7O: (sent 5/12 2:42PM)
Hello Russ, you did an excellent job on placement on the foxes.. here are some times.
Rod KH7L and myself used one vehicle.
start 9am had to divert for non fox reasons 930-10, resumed and found MOI at 12pm code KSQ located light pole king street
took lunch break resumed at 1pm found MOE at 151pm code ARC. we must have went by it 4 times and just didn't see it....or it would have been faster...
winradio wasn't that important today.. it just provided moral support incase your transmitter drifted , I programmed it for a 40khz window to look at. It does a few tricks but more for debugging not for fox hunt.. no bearing info from it.. You can pass on the below info after Sunday night for those interested in what paths we took for MOI
It was really fun, a little frustrating but that's the challenge. It was a little difficult because of the buildings and reflections but not too bad...
started 9am, first bearing at around 930am
detoured off of hunt 945~10 or so
found 12 noon
then took lunch break
1st reading was at alamoana top deck by sears
bearing toward round top and a little east
2nd reading round top (thought it was going to be hell if you had it up there)
bearing punahou school
3rd reading from the beginning of the round top drive
no bearing taken too much reflections
4th went back to same spot on side of road up roundtop and took a more accurate reading
bearing still toward punahou school in that line
5th reading at some park in makiki ? next to keeaumoku ,mauka of freeway
bearing in a line toward alamoana
6th reading from park on south side freeway/keeaumoku
bearing still toward alamoana sig increasing
7th reading from young st. about 100ft off of keeaumoku
bearing exactly where you put it.
8th reading further down young st about 400ft
bearing intersect exactly where you put it.
9th reading walked south 150ft to king st
bearing intersect exactly where you put it
10th reading from some parking lot about 50ft from target
bearing intersect exactly where you put it
11th reading 10ft from target
located!!!!!!!!!!!!!!!! we must have passed by it a few times but always
the next one MOE
started first bearing 1pm
located 151 pm.
1st diamond head look out
bearing toward Leiahi
2nd kcc east side between buildings
bearing toward kahala (error because we were between buildings!!!!)
3rd peetri park
bearing toward Red Cross
4th kiluea near apuwai
bearing toward red cross
5th parking lot 22nd ave off of diamond head road east side red cross less than a block
bearing toward red cross
6th parking lot at movie production place 18th ave off of diamond head road
bearing toward red cross
7th reading 50ft off diamond head road to the lookout
bearing toward red cross
8th diamond head side red cross
(When teased about his times he replied):
ok next time I will use a real antenna instead of 2 welding rods on a paint stick...
(See http://www.qsl.net/kh7o/zl_special.html )
I used a 16mhz offset oscillator and/or attenuator.. it worked until I was within 10feet then I stopped "to smell the coffee" as they say,, I told rod that we are on top of it..... I had forgotten that you said you were going to chain it to a pole so didn't look that way.. a true fox hunt to the end... wonder if people would find it if it was hidden to within say the last 5 feet???
I was using a Kenwood HT, older TH79, and where ever we were in town seem to pick up major intermod so had a rough time with that.. the paint stick was sure convenient to throw in the car. I had a 3 element home made beam in the trunk but was too big to carry around so stuck with the paint stick.. I will try building one to spec for the next time... so when is the next one??? I think everyone is motivated now.. good way for non hams to participate and get them interested in Ham radio....
(Sent 5/12 4:53PM)
Jim and I (WH6GS and AH6NF) found your MOI ("dit dit") fox at 3:05 pm this afternoon. It took awhile! The code on the top of the gray ammo box was KSQ.
It was located on King street, near Keaumoku Street in front of the Department of Agriculture building (chained to a lamp post at the curb). (We could hear it from our house in Kapolei before we left home! It was just loud enough to get a beam heading on it toward Diamond Head.)
We didn't have the time to chase down the MOE ("dit") fox today - maybe tomorrow. We did, however, hear it a few times and got a rough direction, so we have something to go on tomorrow.
Thanks for setting up the hunt. This is fun to be able to do it at our leisure and when time is available.
....(Sent at 10:30PM)
Sorry for the false alarm of sorts, I did manage to pick it up during our evening drive into town about 1830. Crissy and I are about to assemble the RDF antenna and give it a shot. :)
... (Sent at 1:52AM)
I found them.
> At night?
Yup! Crissy and I started out at 23:18, after an evening out. MOE was found at 0000, MOI found at 0108.
We took pictures, too.
(WH7O: Looks like tape measure & PVC beats welding rods & paint stick. Who says you have to spend a lot of money? )
AH7D (Sent 5/13 11:05AM)
I had a little time to find one fox yesterday. It was the MOE fox across the street from the Red Cross Building. Its control code is ARC.
Thanks for setting this hunt up.
AH7QO:(Sent 5/13 5:38PM):
I could only find the RCDH one: ARC for MOE. Couldn't get a good fix on MOI. I used the "steel tape measure" beam, but when I got to Makiki park there at Ke'eaumoku it gave an indication that I was close and that it was more towards Punahou. Then when I got up there, I couldn't pin point it. However, it looked like it was closer the old Hawaii Sugar Plantation Growers building at the park. Then, when I got closer it said back up to the hill with Punahou. Anyway, I got close (at least by the S meter), but didn't get it. A real learning experience. Sunburned all to hell. That optimistic attitude leading one to say, "just a little bit more" will do you in every time.
Please, use my comments. May my ashes fertilize others. I figured out quickly that they were running different power outputs when I sought MOI past Diamond Head theater in an ambulatory mode. Took years off my shoes. Added another rule: Work from your car.
AH6NF: (Sent 5/13 6:45PM)
Jim and I (WH6GS and AH6NF) found your second fox today. Fox MOE ("dit") had the code ARC on the top of the ammo box. It was located on Diamond Head Rd, directly across the street from the entrance to the American Red Cross building. (I assume that you got my e-mail from yesterday saying that we located the MOI ("dit dit") fox yesterday. Code KSQ was on the top of the ammo box. Location was on King Street, near Keeaumoku St., in front of the entrance to the Department of Agriculture.)
Thanks for providing our fun for the weekend. We really enjoyed the hunt.
Please let us know who else participated and who found the foxes. It would be interesting, and I'm sure to others also, to know what equipment you used - what provided the CW audio and the timing, what transmitter, what battery, etc., etc.
Bev and Jim
Check out http://aditl.com/ham/fox/foxhunt0105.html
It has your write-up of the fox hunt and the plot map Bev and I used during the hunt.
NH6PY (Sent 5/13 8:29PM)
I found "MOI" -- KSQ -- this afternoon.
I couldn't find "MOE". I think it's somewhere near the Kilauea Rec Center area, but gave up after two hours of walking around in the sun and spinning myself dizzy.
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