Contact person: President of FWARC – Kato Spears KB3LIB email@example.com
FWARC website: www.fwarc.net
Meet at Food City Parking Lot, 191 St Patrick’s Drive, Waldorf, MD
Social hour 1200 to 1300 after Fox Hunt
1.The event will be a mobile foxhunt starting from the Food Lion Parking Lot 191 St. Patrick’s Drive, Waldorf MD on 6 April 2019 from (0745) 8am to 12pm. Our social will be from 12 to 1pm.
2.The Fox will call every fifteen minutes on 147.555 MHz for two minutes starting at 0800 (0800-0802, 0815-0817, 0830-0832, etc.) and ending at 1200 or until all registered hunters arrive at the den. Clues and hints to the Foxes’ den location will be provided at each 15 minute announcement, becoming more descriptive with each announcement. At 1130, 1145 and 1200, the Foxes will reveal where the den is for anyone still on the hunt. Lunch will be on your own if you want or tasty PB&J. Limited refreshments and treats will be at the den.
3. Participants should listen both on a rig with an omni directional antenna to hear the fox (to confirm it is up) and switch to a rig with a directional antenna to narrow down which direction the fox is transmitting from (based on signal strength and/or nulls and using the process of elimination). In some cases a directional might be needed to hear the fox – DONT rely on your omni at the start point!
4. The participant(s) or partner(s) (navigator) should draw a line on a map from the start point (or their current location) in the direction where they believe the fox is transmitting from. Drawing a fan is recommended in order to conduct better analysis. Speaking of analysis, don’t forget to think about reflections and multipath. (the point of the next two comments is: don’t discount any skeptical lines you may have to the fox, just study the map a little closer and adjust based of what makes sense).
a. Reflections (off of large buildings, metal, wire, etc.) can throw you off. To combat it, study your map to see where this might affect you and find a “next” location that will not have the same object that may throw you off (example, I think my fox is that-a-way however from here to there there are large power lines that could be throwing me off, at my next location I will ensure to get on the other side of those lines and take my next reading). You can and attenuate your antenna as far as possible to help determine the true signal.
b. Multipath – it will be harder to determine true direction or null due to multipath fading. When signals reflect off or refract around objects, they will arrive to the receiver at different times or at the same time causing amplification or fading. To combat this, again study the map, if you are skeptical about your first line to the fox, consider if there is a group of objects between you and the fox and move to another site that does not have these obstacles (between you and where you suspect the fox to be) and try another shot.
5. The team should get in their vehicle(s), move to another good listening location (on high ground perpendicular to the previous line drawn on the map) and repeat until there are at least 3 lines (fans) drawn on the map which intersect. Where the lines intersect, is potentially where the fox is. The more lines drawn, the narrower the area of search will be. Timing and route selection is critical as there are only 4 opportunities to get a solid direction on a map, per hour. Here is where having excellent navigation skills or a partner is crucial. I suggest obtaining a map prior to the hunt and studying “go to” locations in the surrounding areas of the start point. Here is a good map:
6.The team should drive to the potential search location and try to narrow it down even further by repeating the process closer to the fox (benefit of going closer right away is that you will know you made the right decision – instant confirmation) or by continuing to stay further out and get more confirmation before moving in (benefit of stay further out is having more accurate search area before getting into a “signal is all around me” scenario).
(if you find yourself in “the signal is all around me” situation) You may have to decrease the sensitivity of your receiver once you are closer to the fox because it will seem like the transmissions are coming from all directions. You can do this a few ways by:
a. using an electrical attenuator connected between your radio and antenna – click one link below for a good one to purchase
b. slightly rolling off of the frequency (instead of listening to 147.555 try 147.550 or 560, etc).
c. body shield your antenna
d. take off your antenna completely or use a poor antenna
e. cover your antenna with aluminum foil on 3 sides
f. standing in a poor location (low elevation or close edge of a hillside with an opening near the suspected direction – if you get a signal by just peaking around the hill, you can assume the signal is coming from the other side of that piece of terrain and you can eliminate the other direction behind you)
7. Again, repeat the process of determining what direction the strongest transmissions are coming from (or not coming from) and move to the area where you think the fox is.
8.There will be increasingly warmer clues as time goes by.
9.Participants should bring a compass, map, protractor, ruler, pencil, vehicle, VHF radio receiver, directional antenna, omni directional antenna, GPS with “favorites” (places you know will be a good next location after the start point) saved (to get you around safer). Charles recommended using a reciever with AM capability as well.
Boy Scouts and Fox-hunting:
How to Build a Yagi antenna:
Check-in (text) at the number provided in email between 0730 and 0755 to let us know you are participating in the hunt.
Meet and greet other hunters — team up and cross load if needed
Prepare directional antennas and compass and listen for the first Fox clue at 0800 on 147.555 MHz
Record most likely direction “fan” (strongest direction + and – 15 degrees)
Draw the fan or your map and stretch it as far as theoretically possible
Identify another suitable direction finding location and move to it
Listen on the 15s and repeat the direction finding process from two or more locations
Identify where the fans intersect
two choices: Stay far out from where you suspect the fox to be and get more confirmed points (keeps you from getting sucked into an area where you need to use attenuation techniques) or Move to the suspected area and attenuate the signal to get a narrow fan by:
using a poor signal location
using a poor antenna
using an attenuator
using an off frequency
sheilding your antenna
using no antenna
Repeat the direction finding process until you find the fox!
Radio Merit Badge Counselor NCAC
President, Fort Washington Amateur Radio Club