BARC ARDF

ARDF

RADIO FOXHUNTING

The Basingstoke Club (BARC) has run a Foxhunting event virtually every month since 1985! This involves finding one manned transmitter located in a 25km x 25km area. Using a car to navigate to the fox and then usually a on-foot finish to find the hidden transmitter and operator. Rules for this type of event are made at club level usually to reflect the participants skill and the requirement to make it a sociable event.
Follow the side menu for some BARC ARDF projects.

RADIO ORIENTEERING (Radio 'O')

The Basingstoke Club also hosts ARDF events for the RSGB, these being on-foot to IARU rules. These events involves finding up to 5 unmanned, low power hidden transmitters on 2m or 80m in a woodland area typically no bigger than 2km x 2km.

Radio 'O' is in an embryo stage in the UK although well established in other counties. The logistics, equipment and tactics used in Radio 'O' are somewhat different to Foxhunting, for more information see the following links :
Official RSGB UK ARDF website.

Website by BARC member G3ZOI

VHF / UHF FOXHUNTING (mostly by Clive G4ODM !)

This pastime is officially know as ARDF or Amateur Radio Direction Finding, however the original title of Radio Fox-hunting is more widely used.

This facet of Amateur radio encompasses the use of radio receivers with directional aerials. It frequently requires the use of compass and protractor, map reading, driving, navigating, orienteering, cross country running and if one really gets hooked some simple construction. Unlike most other amateur radio facets, this one does enable small teams to take part.

Its an ideal way of getting the XYL (or XYM) involved in your hobby! SWL,s and those studying the RAE should be encouraged to participate. There is always a social part of this hobby, normally at the Pub after the end of the "Hunt" when the reasons for ones failure are analysed in detail and blame attributed as appropriate!.

The "guidelines" tabulated within should be taken as just that, "Guidelines". Any flagrant breaches of agreed use of such guidelines should be debated and drowned in the Pub after the hunt. This is after all a form or relaxation!

ARDF includes :-NAVIGATING, MAP READING, ORIENTEERING, DRIVING, WALKING / RUNNING, CONSTRUCTION, EXPERIMENTATION, FRUSTRATION AND ELATION.

Someone (The Fox) hides with a radio and the rest (hounds) try to find where the fox is. In Europe, Foxhunts normally take place on one of three bands. In the UK its HF on 160 metres or VHF on 2 metres. In Continental Europe HF is on 80 metres and combines strenuous physical exercise. More like a half marathon with radio thrown in!. The saddest in the UK do night multiple events on "top band". Those with a little more sanity take it easier on 2 metres although technically this can be more challenging.

This web site is about our experiences and learning on 2 metre Foxhunting that started in 1985.

WHERE?

ME AND THE MISSUS DO IT IN THE WOODS AT LEAST ONCE A MONTH!

If you wish to keep your band of happy hunters together then don't have too many (any) hunts in towns or hunts that result in sitting in traffic jams at traffic lights.

For an enjoyable "hunt" the country is better and offers many more opportunities. Keep the area reasonably "snug" say a 25 kilometre square if the start is by car or a 2 kilometre square if on foot in a forest. Always have the Pub sorted ready for afterwards. (You have to book Pub lunches nowadays!)

MAPS
Ordanance Survey "Land Ranger" and "Outdoor Leisure" maps are very popular. One should note that a Land Ranger map covers a 40 kilometre square.

HOUNDS

The most important requirement as a hound is to know where you are at all times. For my part I (G4ODM) normally carry a Janet (G6JDP) in the passenger seat. If the Janet is being used as a fox then I use a GPS. I did try keeping one finger on the map at all times when driving but changing gear became difficult !

Next in importance is the MAP. This coupled with a magnetic compass and a straight edge permit one to plot bearings. - provided you know where you are at the time! Now the radio gear, a receiver (or transceiver) but it has to be portable as you are likely to hike with it for a kilometre or so.

A directional antenna. The popular HB9CV can be used, its quite compact but it has a poor front to back ratio and peculiar side lobes. Best compromise is the 4 element short Yagi made by TONA. On 2 metres most hounds look for the strongest signal. (On Top Band they look for the smallest).

Be prepared for inclement weather, make a stiff folder with a polythene cover capable of holding a map folded to expose a 25K square. Use a Chinagraph Pencil on the polythene, this works in the wet.

TAKING THE FIRST BEARING

Chose a high clear point roughly in the centre of the declared area. This will ensure that you have a very good chance of hearing the first transmission.
ALWAYS do a full circle when taking a bearing. Its far too easy to centre up on a back bearing and head off in entirely the wrong direction. When you are sure about the direction line up on a distant object as a reference. Then take your compass bearing. Alternatively, place the map on the ground beforehand and line the top of the map up with true North. Then lower the beam onto the map and draw alongside the central spine of the beam passing through the point where you are.
Make allowance for the difference between magnetic and true north if you have time. Don't worry if you don't. Oh yes, the RED end of the compass needle is North!

WHERE TO GO NEXT
Experience has shown that a straight down the beam heading is normally the best tactic. Take into account the strength of the first transmission knowing that the fox was pointing directly at you. It may well be worth missing the next 2 or 3 transmissions if you believe there is a good distance to travel.

FOXES EQUIPMENT

A 2 Metre transceiver and attendant amplifier if necessary to ensure sufficient radiated power can be provided. As a guide 20 watts is fine from a reasonable vantage point to service a 25K square. Adequate battery capacity to ensure that the station can transmit for the duration of the hunt plus a bit. Antenna. Favourite is the same as that used by the hounds, a 4 element Yagi horizontally polarised and beamed towards the centre of the declared area.

ACCURATE WATCH.
Synchronise with the TV or speaking clock if you don't have a GPS or radio controlled watch. The Fox normally needs to transmit for defined time periods at precise times, so accuracy is important. Transmissions could of course be random, but that's another variant!

CLOTHING & FOOTWARE.
That battered old wax jacket hanging around the garage just in case you need to lay under the car in a puddle is just about right! Jeans or thick old trousers - last used during painting the fence - for the legs and some decent (or indecent) walking boots. Keep a change of clothes in the car for the pub afterwards. If its summer then shorts and "T" shirt. But again keep that change of clothes just in case you are tempted to swim that ditch! And If you do DON'T take your boots off. You never know what's under the water!

COMPASS - If the transmissions are directional and beamed towards the centre of the declared area the fox needs to know where this is.

CREATURE COMFORTS. Sitting still in the middle of a swamp in January and talking into a microphone is cold and thirsty work. Take a flask with some warm drink, Some nibbles, waterproof clothing and something to read from (daily paper) should your thoughts run dry.

OPERATING FREQUENCY
Agree and publicise the operating frequency, and timing of transmissions well beforehand. Don't use S18, 19, 20 or 21 OR 22!

BARC FOXHUNT EXERCISE RULES

LOCATION The fox will transmit a 145.425MHz FM signal from a fixed location, not requiring permission for access or payment of a fee, in a previously declared Ordnance Survey map area, typically 25km by 25km square. The fox will transmit the location at the end of the exercise.
NOTICE The date, start time and map area will be published in advance.
DURATION The exercise ends after an ample 2 hours, or when all hounds have either found the fox or conceded, whichever is the earlier. Hounds without a transmission capability should make their participation known in advance.
FOX’S OPERATION The fox will transmit on time, for 1 minute at the start of every 5 minute period, a horizontally polarised signal, with maximum antenna gain, if not omnidirectional, directed at the centre of the declared map area.
The fox’s effective radiated power should be such that any hounds starting towards the centre of the area in a reasonably high and clear location shall be assured of receiving the fox’s transmission. The power will remain constant, but may be reduced to conserve battery power as the hounds close in.
The fox may issue clues to the location.
HOUNDS OPERATION A hound may have an assistant or assistants. Only the hound may use direction finding equipment and any assistant(s) must stay with the hound or remain in or by the hound’s vehicle. The hounds may start from any location. Taking bearings from home is not permitted.
The hounds may transmit between the fox’s transmissions but should take care not to divulge their location or mislead others and should not transmit once they have found the fox.
RESTRICTIONS The BARC is a responsible club with an enviable national reputation in direction-finding. Hounds will adhere to the terms of their transmitting licence, the RSGB Band Plan, all driving laws, the Highway Code, the Country Code and local Byelaws. Hounds continued membership will be reviewed by the club’s Officials and Committee should they become aware of any breaches. BARC members must satisfy themselves on relevant matters of law and insurance. They participate in these foxhunt exercises at their own risk and on the strict understanding that BARC Officials, the Committee and the club itself are not liable should any member be involved in an accident or other damage.
AFTERWARDS Fox and Hounds to meet in the pub to lick wounds and agree to do better next time !