The whistle is easily hung round your neck on a piece of string, the control card is best waterproofed (if it is not already printed on Tyvek) and then pinned to your outer clothing with safety pins.
The receiver, aerial and compass are best made up into a single unit if possible. Home constructors have a field day building a receiver into the boom of the antenna.
The map needs to be waterproofed on the start line. If you hope to make marks on the outside of the waterproofing, the map must not move about inside its covering. Chinagraph pencils will write on plastic although they do break easily.
Marking the map
Unless you are blessed with incredible powers of memory you must mark some of the information about the bearings and strengths of the Foxes, onto the map. If the weather is fine and dry, you can carry the map unprotected but in the wet this is a real problem. Pulling the map out of a plastic bag, marking it with a pencil and then returning it to the bag is one option. A better idea is to mark on the outside of the plastic cover providing the map does not move about inside the cover. Chinagraph pencils and spirit based felt-tips will do this, although felt tipped pens will run in the wet.
How to decide the order in which to take the Foxes?
This is the hardest part really. Focus on the known location of the finish; try to make some sort of judgement about signal strength and make your decision. What you want to avoid is going to a Fox near the finish and then have to return, in the direction of the start, to find another Fox that you need.
Choice of Receiver
The ideal radio is small, light, an AM receiver with accurate frequency setting. It should possess a very wide range gain control. In reality you will get as close as you can to this ideal. Here are some of the possibilities:
- Use a commercial hand held rig. This will almost inevitably be an FM receiver with a built in limiter. This feature makes DFing harder but far from impossible as evidenced by the hundreds of Club DFers up and down the country.
- Use a commercial AM rig. Even if you find one it will probably be too heavy to cart round.
- Build one of the kits available. See the home page of this site for details of UK sourced kits and ready built receivers.
- 'Roll your own', probably to a published design. In this case the receiver can be integrated into the boom of the antenna.
Multi-path on 144 MHz
In well contoured areas, multi path propagation at vhf has to be overcome by a successful DFer. Here is an account by David Williams of how he overcame the multi path at Transmitter #3 at Eymore Wood.
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