|British Top-Band DF Association|
160 metre DF Equipment
This is a simple tuneable receiver with a directional aerial and a sense aerial. The aerial is either a ferrite rod or a loop. The sense aerial is a telescopic whip. The receiver has a BFO (Beat Frequency Oscillator) so that morse signals can be easily heard; this makes a signal with no speech on it sound like a whistle.
The receiver has controls for:
Headphones are used to keep out background noise making weak signals easier to hear.
These vary considerably and can be used in different ways.
Walking compass. A Silva, or similar make, walking compass fixed to the receiver (away from any magnetic materials including a ferrite rod). The receiver is held in the null position and the bezel of the compass aligned with the needle. The bearing is read off the bezel.
Sighting compass. The receiver is held in the null position at arm's length or on the ground; the compass is held in line with it and sighted along the line of the receiver. The bearing is read directly from the compass.
This is a receiver fixed in the car and used to monitor the transmitter frequencies. Many scan the frequencies automatically. it must be connected to a non-directional receiver.
A 1:50,000 Ordnance Survey map of the area. All the transmitters and the start will be on one map (or an area equal to one map with the boundaries published in advance).
A card for use in the transmitting station DF clock
The type of transmitter most commonly used is one designed by Phil Arnold (G4CFG) and Norman Rathbone (G4KZU). Its main features are:
A specially designed clock which records the times when the competitor's clock card is inserted. This was designed by Phil Arnold (G4CFG). Its features are:
To upload information from DF Clocks
To print the results
Lots of Wire
Tools to get the Wire High into Trees
For example: pole, weights, fishing rod and reel