The function of the Cave Radio & Electronics Group is to provide a forum where electronics enthusiasts and cavers can meet to discuss their ideas, through CREG publications and meetings. You will reach a wide and varied audience throughout the world. We would also like to encourage cavers to provide feedback. You do not have to be an electronics expert to subscribe to our journal - yes, it contains much specialist information, but we hope that it can also be used as a forum for feedback from cavers who will be using electronic equipment.

Following a re-organisation at the 2007 AGM, CREG no longer has "members". All those who pay a fee to receive the journal are "subscribers" with no voting rights. CREG operations are now directed by BCRA Council and BCRA members may exercise control over the group via the BCRA AGM.

• Communications (Low Frequency Inductive Radio, Conventional Radio, UHF radio in tunnels, Guide-wire Radio, Single-wire Telephones, and Earth Current Signalling)
• Radio-location
• Lighting & Battery Chargers
• Electronic Photographic Equipment
• Cave Detection
• Waterproof Electronics
• Caving on the Internet
• History of cave communications
• Underground video techniques
• Data loggers (used by hydrologists and other cave scientists)
• Electric drills underground (for fixing SRT/ladder anchor points)
• Caver counters (for cave conservation purposes)

Right: A television image transmitted from a cave in March 1997. [Mike Bedford].

The Journal caters for most tastes by providing constructional projects, reports of practical experiments, general-interest features and original theoretical papers. Constructional projects have included David Gibson's highly-popular flashgun slave unit, now used by most cave photographers in the UK; Brian Pease's sophisticated radio-location beacon using a narrow-band phase-locked loop and, of course, John Hey's induction radio which has performed very well in trials in the UK and France.

Experimental write-ups have included earth-current techniques as away of improving the range of cave radios, capacitive and inductive couplers for single-wire telephones, radio spectrum surveys, speech processing, and experiments with a variety of VHF and UHF radios in tunnels.

General-interest features have looked at video techniques underground, electronic bat detection, the use of telephones for cave exploration in the 19th century. We have had several "special features" on lighting, photography and computing. For the theoretician we have discussed - amongst many topics - losses in tuning capacitors, receiver front-end design, bandwidth v. performance issues, earth current principles, myths surrounding impedance-matching of amplifiers, use of solar panels, and so on.

Letters to the Editor: We welcome letters to publish in the Journal. Whatever your interest, you might find others who are willing to share information. So whether your interest is magnetic field surveys for archaeology, VLF behaviour during earthquakes, metal detectors, video techniques, medical devices (e.g. TENS pain relief equipment, pulse oximeters), diving equipment, sensors for earth science research, earthquake monitoring, or some other "fringe" activity; we would like to hear from you.

You can view a list of CREG journal articles, indexed by journal issue, and you can search a database of CREG articles as part of BCRA's Science Index. Our Bibliography of Underground Communications is now out of print.

We try to organise field meetings from time to time, although this depends on volunteer effort being available. Field meetings allow people to demonstrate equipment and techniques, carry out experiments, and share ideas. The exact programmes differ, depending on the interests of those attending, but typically include practical work during the days, and a few short talks or slide shows on the Saturday evening. Usually, there is also plenty of time to discuss issues informally over a pint in a local pub. Many people have had their introduction to cave radio through our field meetings, and we have welcomed visitors from France, Belgium, Canada and the USA. In 2007 we organised a Cave Technology Symposium, an event which repeated in 2008 and will, hopefully, be a regular occurance in the future.

The following activities have featured at field meetings over the last few years...

• Training in radio-location techniques
• Demonstrations of new cave radios
• Talks on GPS, licensing, speech compression
• Discussion on electronic aids for cave photographers
• Experiments with capacitively-coupled single wire telephones
• Demonstration of cave detection by earth resistance measurement
• Field tests of new commercial induction radios and carrier-based single-wire telephones
• Experiments with an earth-current/induction radio hybrid system
• Underground operation on the 73kHz amateur radio band
• Demonstration of equipment for scanning the LF band
• Tests with emergency lighting based on high brightness LEDs

We have four HeyPhones sets and a pair (i.e. transmitter and receiver) of Pease Radiolocation beacons. These are available for hire. Obviously a lot of time and money has gone into their construction and we do not want to lose them, so we will usually ask you for a deposit to cover the entire replacement cost. For the HeyPhones, this is around £350 each. We also need you to pay the shipping costs in both directions, which can be well over £100. Because of problems with Customs, and because we might need the equipment for UK use, we will not normally ship this equipment outside Europe. However, please enquire, as the situation may change.

BCRA has agreed to provide self-insurance cover for the loan of HeyPhone and similar equipment. The terms of the scheme are set out below.

• CREG will charge borrowers a 5% fee for the loan of equipment.
• Where borrowers of equipment have their own insurance then it should be made clear to them that the equipment should be covered under that policy, otherwise BCRA will cover any losses.
• All equipment under loan must be notified to BCRA Treasurer. This should include details of the borrower, the equipment and the period of the loan. No notification in advance means the equipment is not covered.
• Losses covered by BCRA will not exceed the value of the equipment as indicated on CREG's list of equipment. In arriving at the loss, allaccumulated hire fees will be deducted i.e. CREG will contribute these funds (if any) to a replacement.
• This agreement will be reviewed periodically, in particular to ascertain whether CREG has accumulated sufficient funds to cover losses itself.

For further information, including subscription rates, please go to our Payments page. Following a re-organisation at the 2007 AGM, CREG no longer has "members". All those who pay a fee to receive the journal are "subscribers" with no voting rights. CREG operations are now directed by BCRA Council and BCRA members may exercise control over the group via the BCRA AGM.