The British Caving Association

UK Cave Technology Symposium 2011

9am to 5pm, Saturday 9 April 2011, Hulland Ward Village Hall, near Ashbourne, Derbyshire, UK. Admission discount for BCRA members. This is the venue we visited in 2007 for the first of these symposiums. Doors open at 08:15 for breakfast. Tea, coffee bacon butties and toast will be available

As usual, this one-day symposium - organised by BCRA’s special interest groups CREG and CSG - is expected to coincide with the Cave Surveying Group's spring field meeting. Field trips and 'classroom' sessions (CREG and CSG) may be offered on the Sunday, and will be announced in due course. Abstracts of talks (or at the very least, titles!) are requested by 1 March 2011. This year, the lecture secretary is myself, David Gibson. Accommodation and CSG activities are being handled by Allan Richardson. The address tech-sym@bcra.org.uk will reach us both.

I would particularly like to include a photography and video theme this year, so if you wish to talk about video editing software, video lighting, unusual digital techniques or whatever ... please start thinking about it now! Further information will be sent out by email in due course to those who are registered with the tech-sym announcement list at http://list.bcra.org.uk. Information will also be posted from time to time to the BCRA news forum at http://bcra.org.uk/forum

Copies of last year's presentations are available at http://bcra.org.uk/proc, together with a copy of Mike Bedford's report that appeared in CREG journal 74. A version of this article will appear in the next issue of Speleology.
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Items offered so far for the programme are as follows.
Last update, Wednesday 6 April at 11:00am

Surveying Session

Kevin Dixon - Surveying Technology, incl. Laser Scanning
SatNav for surface surveying, technology, cost, limitations, accuracy, why water can appear to flow uphill and maps can be disagreeable. Laser scanner development for 3D cave surveying and visualisation, technology used. Example data to be presented subject to tests on return from Mulu expedition

Photography / Video Session

Mike Bedford - High Dynamic Range Photography
The dynamic range achievable with conventional photography is poor compared to the human eye. This means that in high contrast scenes either the highlights are overexposed or the shadows are underexposed. The newly popularised technique of High Dynamic Range (HDR) photography overcomes this limitation and in so doing either records a scene closer to the way the eye sees it or goes beyond this to create a truly dramatic image. Few scenes have a higher dynamic range than those in the vicinity of cave entrances - either looking out or looking in - which prompted Mike's interest in HDR work. This presentation introduces the concept of HDR photography and provides some practical tips on how to take HDR photographs. The talk is illustrated with examples in the areas of landscape and interior architecture - both well suited to the HDR technique - plus some caving scenes as you've never seen them before.

Michael Topsom - Using Internet tools to process photos in 3D
I have two working examples of the techniques I'm using to make 3D models from a set of 2D photographs (Photogrammetry). You can see video examples at http://www.youtube.com/watch?v=svvFcafvjME and http://www.youtube.com/watch?v=fegyR6Y292o . The models are of a bear and bat skeleton respectively, the bat can be hard to spot at first. I've also started looking into the possibility of using these techniques on other formations and general cave passage.

Footleg - Video/AV editing using Sony Vegas Home Studio
and other interesting ideas for cave AV sequences using other software.

Hidden Earth Video Salon
We will show some videos from recent competitions, and this will possibly include a dicussion on editing techniques.

Communications Session

Jon Whiteley - Mountain and Cave Rescue using the SarCall system
Sarcall is a system that has been developed to assist with the call out of Mountain and Cave Rescue Teams across the UK and Ireland.  Jon Whiteley who acts as the rescue controller for Devon Cave Rescue Organisation and who is one of the SARCALL regional administrators will describe and give a live demonstration of the system. The system has been developed and built by John Hulse (Ogwen Valley Mountain Rescue). The number of mountain and cave rescue teams across the UK that have now implemented the system to call out their members is constantly growing. Currently the cave rescue teams that have bought into the system include the Cave Rescue Organisation, North Wales Cave Rescue Organisation, Devon Cave Rescue Organisation and Cumbria Ore Mines Rescue Unit. Gloucester Cave Rescue Group and Mendip Cave Rescue Organisation are currently reviewing the possible usage and other teams are watching progress. The system uses email and SMS messaging and is accessible by both the teams and the "Calling Authorities" (usually the Police). The system provides an audit trail of what information was received from the original 999 caller and transfers this information accurately to the team leaders and then to onward to team members, eliminating the risk of confusing messages about the nature and scope of the call out and important information like RV points which, over years, have proven to become the basis of Chinese whispers. Although the system is not directly accessible to the everyday caver, this presentation will provide information on how cave rescue teams are responding to the need to develop and change and on how the usage of common messaging systems is taking place across an integrated platform.

David Gibson - How Earth Current Antennas Really Work
With cave radio equipment such as the HeyPhone and Nicola system there has been a trend away from the use of induction loop antennas towards earth-current antennas, i.e. long wires grounded at both ends. However, the popular explanation for how these antennas work is fallacious. They do not operate by allowing the current to flow in a 'big loop' in the ground and in fact, they do not depend, fundamentally, on current flow in the ground at all. The fact that the popular explanation is wrong is important because, if we do not understand how the antenna works, it is difficult to know the best way to use it, or how to design a better one. Back in 2003, I wrote an article for the CREG journal entitled 'What We Don’t Know About Earth-Current Propagation'. It has taken me some time to get to grips with the problem but this talk will now go some way to filling in the gaps in this knowledge and will describe a method of experimentally rating earth-current antennas for effectiveness.

David Gibson - Link Budget Calculations for Underground Communications
A link budget is a statement that accounts for the various losses in a radio communications system. Such calculations are familiar to radio engineers dealing with radiated signals. However, for subterranean or submarine communications, where the antennas do not usually radiate any power, the conventional notion of a link budget has to be modified. In my professional life, I am frequently asked to provide estimates of transmission range for proposed long-distance non-radiating systems. Two recent examples include a proposed mines rescue system that was required to transmit through 1000m of rock, and an oil drilling application that was required to transmit 6000m below the seabed. Such distances are, of course, impossible to achieve without extremely large antennas and huge power budgets. However, it is sometime difficult to convince a radio engineer, who is used to the conventional notion of a link budget, of the impossibility of the task. "If we can transmit signals across interplanetary space using just a few watts, why cant we transmit through 1000m of rock?".

Further Information

Latest update 15 March

Saturday Programme. There is no pre-registration for this event (although it will be useful if could could let us know, so we can get enough food in). There will be a small admission charge on the door with a discount for BCRA members. Speakers will not be charged. Tea, coffee and light refreshments will be available for a small fee. Bacon butties and toast will be available for breakfast from 8.15am.There is a local pub which will provide meals at lunchtime but it tends to be busy and you may prefer to bring your own packed lunch. BCRA publications will be on sale and all delegates will be offered a free copy of BCRA's Cave Surveying booklet (Cave Studies Series #11). http://bcra.org.uk/pub/cs/index.html?j=11

A programme of events is gradually coming together, and has been posted to this forum (see above). There is still an opportunity for you to offer to give a talk. We would particularly like to include a photography and video theme this year, so if you wish to talk about video editing software, video lighting, unusual digital techniques or whatever ... please let us know.

Accommodation. Accommodation for the Saturday night has been booked in a local caving cottage. Accommodation and CSG activities are being handled by Allan Richardson. The address tech-sym@bcra.org.uk will reach both Allan and the lecture secretary David Gibson.

Sunday Programme. In addition, for those of you staying in the area for the weekend, BCRA's Cave Surveying hopes to be providing "paperless surveying training" on the Sunday, following on from last year's practical session on the use of DistoX and calibration. This will take place at BCRA's Library at Glutton Bridge (near to Buxton) and, if there is a demand, there may also be some underground practical training. Numbers may be limited unless we can find extra volunteers to give training sessions, so please contact us if you can help. If you wish to participate you must contact us or turn up on the Saturday, as final arrangements will not be made until then. It is likely that the library will be used for a CREG classroom session in the morning and a CSG training session in the afternoon, but this is not certain so, to avoid disappointment you must keep in touch!
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