speleonics 9winter-spring

1987-88

"BETTER CAVING THROUGH ELECTRICAL STUFF" vol ume III nl.ll1ber 1

COIlTEITS

-.-~--:~.~..... ,

JUST FOR FUN (Editorial) 1

NEWS AND ANNOUNCEMENTS ..., 2Informal Section Meeting at

Dayton HamfestAddress ChangeAntennasSection Members PublishBritish Forming Cave-Electronics

Group (reprints)Radio Information AvailableAvalanche Beacon Info WantedLightbulb Data WantedComputer "Cave Net" EstablishedNew LORAN-C Transmitters to

Fill Mid-continent GapTaking Data Underground (reprint)

LETTERS. . . . . . . . . . . . . . . . . . . . . . . . .. 4

Roy Charl tonLuther StroudMax Carter

SENSITIVE SLAVE-FLASHFOR CAVE PHOTOGRAPHY (reprint)

Bo Lenand er, SM5CJW " 5

RECENT DEVELOPMENTS INSUPERCONDUCTIVITY RESEARCH

Luther Stroud 6

NO.4 NO.6 NO.8

A CAVERADIO IN THE FIELD -SUJOtER 1987

Ian Drummond 7

,p

RADIOBA T

"A" STORAGE "B"BA TTERIES

Magnetic Moments #7:ELECTROMAGNETICNOISE-IATURAL SOURCES OF NOISE

I an Dr ummond 9

BATTERY DATE-CODESStan 1 ey F. Quayl e 11

MORSECODEAPTITUDETESTFrank Reid, Richard Blenz .,... 11

RESOURCES. . . . . . . . . . . . . . . . . . . . . ., 11

THEMINI-MAGLITEtm AND VARIANTS:ELECTRICAL TESTS AND CAVERMODIFICATIONS

Frank Reid 12

IN REVIEW:Electronic hypothermia-alarm,

four cave-light articles,South African mine radio 13 Multiple Storage Battery Corporation

FREQUENCIES OF INTEREST:1988ISS CONVENTION , 13

ELECTRONIC WRISTWATCHMAKESEMERGENCYFLASHLIGHT

Frank Reid 14

(Above): Giant No.8 dry cell with bat trademark, circa1906, beside more-famil iar No.6 size. The number indicatesheight: #6 is 6 inches tall. (Below): Another old BATtery.

(From .Collecting Early Radio Batteries" by Bob Allen, TheOld Timer's Bu11 et in Feb. 1988. see RESOURCES,p. 11). -

Volume III, Number 1.

SPELEONICS 9

Fall-Winter 1987-88

SPELEONICS is the quarterly newsletter of theCommunication and Electronics Section of theNational Speleological Society. Primary interestsinclude cave radio, underground COll111unication andinstrumentation, cave rescue communications, cavelighting, and cave-related applications of amateurrad io. NSS membership is encouraged but notrequ ired.

Section membership, which includes four issues ofSPELEONICS, is $4.00in USA/Canada/Mexico, $6.00owerseas. Send subscriptions to section treasurerJoe Giddens at the address below (make checkspayable to SPELEONICS). If you have a ham-radiocallsign or NSS membership number, please includethem when subscribing.

Clla;rwan (and ed itorof issue '11):

Sec~etary (and editorof this issue):

Frank Reid, W9MKVPO Box 5283Bloomington, Ind iana47407-52B3

I an Dr ull1110nd5619 Dalwood Way NWCalgary, AlbertaCANADA T3A IS6

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JUST FOR FUN...

How would YOUdesign a powered vehicle for haulinga caver through a crawl way?

Nevin Davis' famous precedent, the Motorized As-cending Device (MAD), is a man-carrying, gasoline-powered rope climber. It was demonstrated toenthusiastic crowds at the 1970 NSS Convention inState College, Pennsylvania, and used successfullyin Sotano de las Golondrinas and other large pits.

Some caves have wide, smooth-floored crawlways; inCoac h Cave (Kentucky), cavers used snow-coast i ng"saucers" for dragging heavy ropes and equipment,and later built 4-wheeled carts called "CRABs"(Crawlway Reconnaissance And Bivouac). The CRABswere very successful, especially when one was usedto haul an injured caver through the 1200-footcrawlway. Where ceiling height permits, a cavercan support his upper body on the cart and use hisfeet for propulsion.

The effort of actually building a powered crawleris probably better spent elsewhere. On the otherhand, anticipated advances in motors and energystorage could make them practical, and revolution-ize other areas of caving-- See the article byLuthe~ Stroud in this issue.

Practical or not, a crawler would be great fun todrive around caving convention campgrounds, undervehicles, etc. It would make a good project foran engineering-school design competition. Oneenvisions a "crawl off" with prizes for speed,range, minimum height, obstacle negotiation, etc.

Share your though-experiments or bring them to theNSS Convention Electronics Session. In the inter-est of safety and conservation, we will disallownuclear "subterrenes" which make their own tun-nels. We will not otherwise debate ethics ofpowered caving; this is only an exercise in imag-ination. Some ideas already suggested are:

"It should be an articulated tracked or multi-wheel-drive vehicle... Motors from battery-powered

Foreign subscription can be paid in U.S. "paper"dollars in the mail; an international money-ordermay cost as much as the subscription. Manymembers have sent cash without problems.

Editorship rotates among the officers. Volunteersare encouraged to guest-edit or produce an issue.A technical session, followed by election ofofficers, is an annual event held during the NSSConvention.

Complimentary copies of SPELEONICS are mailed toNSS offices and sections, the U.S. Bureau ofMines, U.S. Geological Survey, and the LongwaveClub of America.

Treasurer (and editorof the next issue):

Joe Giddens, N5IOZPO Box 170274Arl i ngton, Texas76003

Publisher:

Diana E. George, N9DEJ1869 Trevilian WayLouisville, Kentucky40205

Editorial =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=.=-

kiddie cars might be suitable."

"Like the MAD, but horizontal;through the crawlway."

string a rope

"It should be amphibious... Counter-rotatingauger propulsion would work in mud and water..."

"Agasoline-electric drive could switch to batterylike a submarine when it goes below the surface...The gas motor could be left behind."

"Motorized Stokes litter: Driver lies on back orstomach, steers with ropes or foot pedals... Thiswould need mirrors, windows and a side escape-hatch... Use vertical curb-feelers to warn of lowce ili ng."

driveco u1d

"A loop of conveyor belt with caver andmechanism inside the loop might work if yousteer it... maybe by dragging feet outside."

"Attach hydraulic cylinders beneath caver's fore-arms; pistons extend rearward from the elbows topush him forward. Hands control valves... Caverwears teflon coveralls and wheeled kneepads...Drag the power supply on a trailer."

"It should be an analog of nature... A snail-likemechanism which crawls by sequentially inflatingand deflating rubber tubes on the bottom, a slith-ering mechanical snake, side-winding inchworm,mechanical centipede, or earthworm-like dev icewhich elongates, holds on, and contracts."

thrust,Steering: Handlebars, ropes, asymetricaircraft-style rudder/brake pedals...

"It should have remote control so that the vehiclecan be fully loaded with equipment, and steered byan accompanying caver."

"Caving dogs used as beasts of burden cannot nego-tiate many obstacles... Genetically engineereddog-sized domesticated slugs with appropriateload-bearing collars and harnesses would workbetter, except in salt mines, of course..."

1

- lEKS AND ANNOUNCEMEITS -

speleonics 9v. III no. 1 ~inter.Sprlng1987.88

INFORMAL SECTION MEETING AT DAYTON HAMFEST

luther Stroud writes, "I plan to attend the DaytonHamfest. Maybe I can meet some of the othermembers there. If you publish a list of othersthat plan to go, that would be helpful also."

Great Idea, especially since many of our membersare non-cavers and do not attend the NSSConvention! I already know at least 10 memberswho will be there. Let's meet at II AM local ti.eon Saturda" April 30, on the right side of theticket-sales room inside the front entrance. I'lltape a SPELEONICS cover to the wall. I willattempt to find a quiet place to sit and talk (noguarantees). Perhaps it will become an annualevent!

The Dayton Hamvention (Dayton, Ohio, April 29 -May 1) is the world's largest hamfest. It's agood place to shop for cave radio parts, and awonderful experience for anyone who loves elec-tronics. For details, see January 1988 issue ofany U.S. ham magazine, ask anyone who has beenthere, or write to Frank Reid.

ADDRESS CHANGE

The new post office in Bloomington, Indiana is anice facility, however, they have changed onedigit of the postal code (ZIP) of the SPELEONICSmailing address. Effective January I, 1988, thenew code is 47407-5283. So far, the last 4 digitsare optional.

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ANTENNAS

SPELEONICS #11 will be on the topic of antennasfor cave radios.

* CONSTRUCTION DETAILS

* THE LARGEST* TESTING METHODS* SPECTACULAR BURN-UPS* E-FIELD ANTENNAS

* DESIGN METHODS

* THE TOUGHEST* UNDERWATER UNITS

* THE SMALLEST

* CALIBRATION

We need PHOTOS, SKETCHES, ARTICLES, STORIES.

Please send material to Ian Drummond or Frank Reid(Addresses in masthead).

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SECTION MEMBERS PUBLISH

John R. Barnes (NSS 17192), electronics engineerat IBM in Lexington, Kentucky, has publishedELECTRONIC DESIGN: INTERFERENCE AND NOISE CONTROLTECHNIQUES (Prentice-Hall 1987, ISBN 0-13-252123-7) $30.67. He has donated a copy to the Section.

luther Stroud publ ished "Phone Sentry" in December1987 HANDS-ON ELECTRONICS magazine. He has writ-ten an article to be published about June, 1988 inRADIO-ELECTRONICS, about a one-MHz frequencystandard of extreme accuracy derived by phase-locking to the 3.58-MHz television color-burstfrequency, inductively coupled to any nearby tele-vision set. (R-E, by the way, now carries Don

lancaster's monthly MHardwareformerly in MODERN ELECTRONICS.)

HackerM co1urnn,

BRITISH FORMING CAVE-ELECTRONICS GROUp.

CAVE RADIO SYSTEMS FOR COMMUNICATION AND SURVEYING

"A discussion session...was an opportunity forvarious people who had been involved with differ-ent systems to discuss ways of co-operating tohelp the development of different systems. Themeeting resulted in the setting up of a Msubjectgroup" of thos interested enough to keep in con-tact via some sort of newsletter and the desire tohold a study weekend in 1988."

[from "1987 BCRA National Caving Conference lec-ture Review," BCRA Caves & Caving No. 38, Winter,1987, p. 45. Contr1DUtea-by Angelo George and IanDr_ond.]

Also from Caves and Caving No. 38:

PROPOSED SCRA RADIO &ELECTRONICS GROUP

At the BCRA Conference, a discussion was heldon the subject of cave radio systems. It soonbecame apparent that quite a few people wereworking on various systems but it seemed thatthere was a lack of any communication betweenthese various persons and groups. To this end, itwas decided to "get it together" and start anewsletter to keep all interested parties in touchwith each other and provide. a framework withinwhich ideas and thoughts could be exchanged ordiscussed. Later in the Conference discussion, thesubject changed to other applications of electronicswithin caving. In this context, one can see theadvance of computers for survey and logging workand also the advance of electronic systems foractual survey measurements and location. Theproposed newsletter could also carry news andviews of this type of work, in fact forming a muchneeded communication for this new and rapidlyexpanding field of caving.

In order to get the thing off the ground, I need toknow who is interested and what their interests are.I would therefore, ask anyone who is interested inradio and electronics within caving (amateur orprofessional) no matter what their specific interestis, to ce>ntact me at the address below:

PHIL INGHAM, 49 Highfield Road, Farnworth,Bolton, BL40AH. Tel. 0204791918

Congratulations and best wishes of success to ourBritish colleagues! We hope to exchange newslet-ters and other information.

2

Icom Ken wood Yaesu------- ------- --------IC-2AT 2600 FT-23RIC-02AT TS430S FT-727RIC-04AT 940 FT-757GXIC -28AIC-28HIC-720 TempoI C-735IC -7 45 51IC-751

speleonics 9v. III no. 1 Winter-Spring 1987-88

ANIOUNCENENTS (continued):

RADIO INFORMATION AVAILABLE

Our file of radio information potentially valuablein cave rescue includes the following:

* U.S. National Park Service radio frequencies.

* How to modify the following types of Japaneseamateur-radio transceivers for operation out-side the ham bands:

The information is collected from magazines andother sources. If you have similar informationnot on the list, please share with us. Copies ofspecific items are available from Frank Reid forSASE. Please don't request the entire file; it'smuch too large (same policy as NSS Cave Files).

AVALANCHE BEACON INFORMATION WANTED

"Avalanche Beacon" transmitt~rs carried by skiershelp rescuers find them if they are buried by anavalanche. Austrian caver Peter Ludwig reportsthat their range is only about 200 feet. Recrea-tional Equipment Inc. of Seattle sells ORTOVOX-brand avalanche transceivers ("Switches betweenreceive and transmit at 2.275'kHz and 457 kHzsimultaneously... Compatible with units used inNorth America and Europe... Two 1.5V batterieswith 300-hour life..." 7/8 x 3 x 6 inches, 11oz., $180.00).

Avalanche beacons or derivatives thereof might beuseful as cave radios, perhaps with external amp-lifiers and antennas. They're obviously rare herein the Midwest; anyone knowing details of theircircuitry, especially that of the receivers,please contact Frank Reid.

LIGHTBULB DATA VANTED

Grotto newsletters have published tables of data(voltage, current, etc.) for miniature 1ightbu1bslikely to be used by cavers.l,2,3 SPELEONICSpublisher Diana E8erson George notes that with somany new and exotic bulbs now available, the datashould be updated. Cavers use everything fromtiny Mini-Maglite(tm) bulbs to quartz-halogenautomotive lamps. The editors of SPELEONICS seeka volunteer for this project. We also need a newarticle on the physics of tungsten 1ightbu1bs,discussing voltage versus output and life, effectof inert gasses in bulbs, the tungsten-halogencycle, etc.

References:---.-------

1. Varnedoe, Bill. "About Electric Lights,"Huntsville Grotto News v8 #7,8,9. reprinted:Speleo Digest 1967 p. 3-44.

2. Crombie~ Ed. "A Survey of Electric CavingLights and Techniques," Cascade Caver 16(4)31-37. reprinted: Spe1eo Digest 1977 p. 301.

3. Vaughn, Michael T. "Electric Caving," GCGElectric Caver vI #1, p. 5-6. #2 p. 13-17.reprinted: Spe1eo Digest 1963 p. 3-62.

COMPUTER -CAVE NET- ESTABLISHED

An electronic mailing-list of cavers is beingformed. Anyone interested in joining should replyto Ron Lussier (address below). Include your loca-tion, locations where you've caved, NSS' if youhave one, net address and path(s), and any otherinformation you want to throw in.

+ + +

j

Grendel!

j

ARPA: Lussier@BCD-Multics

j

{.} USMAIL:Ron Lussier918 St. James Pl.

~~~~~~~~~~~!~~~~~~~~~----

We would also like to compile a list of e-mailaddresses of SPELEONICS subscribers. Send to:

Frank ReidPO Box 5283Bloomington, IN 47407-5283

reid@gold.bacs.indiana.edu.arpaBITNET: reid@iubacs

NEV lORAN-C TRANSMITTERS TO FILL MID-CONTINENT GAP

Aviation Week & Space Technology magazine (Sept.l:Ij, lYI:I/,---p:"T2UT1"eports tnat four new stationsof the LORAN-C radionavigation system will fill alarge area of west-central US where signal Qua1itlhas been marginal (see "LORAN-C for Cavers,SPELEONICS 5; updated reprint: COMPASS& TAPE, v.5, #1, Summer 1987). To be operational by 1990,the new transmitters will also cover southernportions of Alberta, Saskatchewan and Manitoba,and northern Mexico. The AWSTarticle includesmaps of the new coverage areas.

Kingdom),From SUNDAY TIMES (United1987: - -

TAKING DATA UNDERGROUND

5th July,

"An electronic life-line could be a big boost forthe safety ,of Britain's 24,000 pot-ho1ers. Thedev ice, developed by students at York University,transmits data instead of the human voice - anunderground first.

Pot-ho1ers key in messages on a water-proofed wordprocessor which transmits the messages as digitalcode. These are decoded on the surface, anddisplayed on a small screen.

The light-weight system, which s no bigger than acar battery, and comes complete with batterypower-pack and transmitter, uses ultra-lowfrequency electro-magnetic waves to combat theage-old problem of speech becoming garbled when itpasses through conductive rock, such as limestone.

3

AIIOUNCEMEITS(contunued):

The device, which is carried underground in aWorld War 2 ammunition can, presently works justone way, but is capable of being adapted for two-way performance. So far it has been successfullytested at depths of up to 600 feet.

electronic"The key

means ofand it is

needs less

Dr. Andy Marvin, senior lecturer inengineering at York University says:entry system is a more efficienttransmitting the same amount of data,smaller than a voice system, so itpower to transmit.

"As far as we know, this is the first time textmaterial has been used underground as opposed tovoice. So far only 400 pounds has been spent ondeveloping it, but the system may have significantadvantages if it works well at greater depths. Itwould be quick and simple to transmit a message ifsomebody had an accident."

The means of underground communication favoured byBritain's five cave rescue teams up to now hasbeen the "mole phone" developed at LancasterUniversity. It passes messages by modulating amagnetic field and can operate up to depths of

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Dear Joe,

...Underground pipelines, power lines, telephonelines, fences and other metallic lines can carrycave radio signals for long distances. Don't knowhow much distortion of magnetic field shape canoccur near ground zero.

At Bened ict' s cave, Greenbriar Co. WV, an under-ground noise source was found and ground zero(roughly) was determined. Later, cave. passageswere discovered in the immediate area. The sourcewas never determined. I wonder if anyone else hashad such an experience.

Roy CharltonRt. 2 Box 42

Dilwyn, Virginia 23936

Ian DrU880nd encountered a field-distortionanomaly in New Mexico, reported in this issue.Earl Biffle of Missouri detected an undergroundnoise source believed to be a gas pipeline whichwas parallel to large power lines, and may havebeen carrying ground-return current.

There may be unusual effects at 2025 Hz, theproton-precession frequency of water molecules inthe earth's magnetic field (see The ScientificAmerican, February 1968, p. 124)~ NOlse m1gntcoula come from natural or power-line-inducedcurrents in the ground, which become concentratedor forced to change direction by anomalies such ascave passage or vertical joints. If mineral crys.tals form nonlinear junctions causing suchcurrents to intermodulate, then perhaps two cur-rents of different frequencies could be injectedinto the ground, and a receiver tuned to their sumor difference could be used for prospecting.

Roy's observation is certainly worth furtherstudy! It would be interesting to search for othernoise sources, measure shapes of their associated

Iptleanics 9v. III no. 1 ~inter-Sprlng1987-88

1,000 feet in good conditions. But each set costs1,400 pounds, which is an expensive item for hard-pressed cave rescue team budgets.

Members of the York University Caving Club will begiving the electronic life-line its full fieldtrials when they set off for the deep caves ofPicos De Europa in northern Spain tomorrow.

Further uses could be in the surveying of caves.When cavers are camped underground, the surfaceparty can pass on messages such as the state ofthe weather. Deep cave expeditions spending along time underground would benefit as well.

Bill Whitehouse, chairman of the British CaveRescue Association, says: "With conventional voicesets there's no problem through 300 feet of rock;the problem comes when you go deeper than that.

"You have to step up the power for less and lessadditional range. There comes a stage where youcould plug a power station in and it wouldn't doto well." --Martin Charlesworth

[Contributed by Ian DrU88ond]

LETTERS =-=-=-=-=-=-=-:-=-=-=-=-=-:-:-:-:-=-:-=-:-=-=-=-

magnetic fields, study frequency spectra, anddetermine if the noise varies with day/night,seasons, wet/dry weather, etc. --FR

Dear Joe,

...1 hope this copy of an article fromElectronics Australia about a 13-kHz receiverhelps further your research on underground radio.I really enjoy reading Speleonics and plan tocontribute an article in the future. I am open tosuggestions from other members for a subject towrite about.

Sincerely, Luther M. Stroud

P.O. Box 1951Fort Worth, IX 76101

Luther sent "Omega Derived Frequency Standard" byIan Pogson, VK2AZN, in Electronics Australiamagazine, May 1987, p. 92. ~oples OT the lu-pagearticle are available from Frank Reid for SASEwith 2-ounce postage (39 cents in USA).

Advanced weak-signal recovery techniques requirevery stable frequency control. Many designs existfor oscillators which are locked to LORAN-C (100kHz) and WWVB(60 kHz) signals, which are diffi-cult to receive underground. The worldwide Omeganavigation system uses very powerful transmittersbetween 10 and 14 kHz (see chart, from above-mentioned article). The Soviet Union operates asimilar system called Alpha. Frequencies arecontrolled by cesium-beam atomic clocks, accurateto a few parts in 1013.

An early version of my own cave-radio surfacereceiver detected Omega signals, a pattern of one-second tones repeating every 10 seconds. Omegashould be detectable underground. The 13.0-kHzfrequency is unique to the Australian station, sothe frequency standard would require modification

4

speleclnics 9v. III no. 1 Winter' Spring 1987-88LETTERS (contunued):

to work with the USA's Omega transmitters in NorthDakota and Hawaii.

I sent a copy of the Australian article to MaxCArter, who experiments with BPSK (binary phase-shift keying) modulation. He has received low-speed data more than 100 miles from his one-watttransmitter in the 1750m "Lowfer" band. BPSKrequires precise frequency control. Max replies,

"... The Omega standard uses roughly the samemethod I use with WWVB. Looks like the stand-ard could be simplified somewhat by using a4046 to generate the 13 kHz instead of theharmonic filter shown.

I see by Speleonics that cavers still have notdiscovered the ultimate underground communica-tions system yet. Finding the right combina-tion of power sonsumption, weight, ease-of-operation and range at the right price is adifficult challenge! I haven't given muchthought to the question of underground datatransmission lately but it seems to me that ifLowfer BPSK ever becomes viable, the techniquescould easily be adapted to cave use. Forinstance, the. second IF frequency for thelatest BPSK receiver design is 1888 Hz, notthat far removed from caver frequencies."

Max lives in eastern Wyoming, near the 1988 NSSConvention. We hope he will attend the electronicssession and demonstrate BPSK. --FR

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SENSITIVE SLAVE-FLASH FOR CAVE PHOTOGRAPHY

by Bo Lenander, SM5CJW

[Abridged reprint of original 2-page article in Swedish. Illustrations and notes are reproduced here:]

The trigger circuit is extremely sensitive topulsed light but not to carbide or electric light.The trigger works without problem with indirectlight. The slave trigger is...so sensitive thatyou can flash the main flash within your flat andthe slave will trigger wherever it is within thehouse (almost)! This system has proved to be afast and easy way to get reasonably good cavepictures without disturbing the non-photographersof the caving team.

A small computerflash is mounted on the camera,set for one-step underexposure to create a darkforeground. An assistant carries a more powerfulcomputerflash working as a slave flash set to givecorrect exposure in the rest of the picture. Thecamera is always set to the working aperture ofthe slave flash.

On my camera is a small f1 ash "Minolta Auto llX8"with one-step underexposure. The slave is a "Nis-sin 28TSO Thyristor-SO" which gives correctexposure... I have used it together with 200-ASAfi 1m:

Auto setting

~~~-~~~--l--~~~~~:~--+--~~~~~~-f/4

I

redI

redf/8 yellow green

+6 Volts is taken from the flash.

I

IPhotodiode 2-5mm2

_The LED is only an indicator.

A computerf1ash automatically varies its output tomake a correct expoure. Film speed and cameraaperture are set on dials, and a photocell detectslight reflected from the subject. The flash isterminated when the proper amount of light hasbeen received.

NOTE: Before building this circuit, measure thevoltage at the trigger terminals of your flashunit. The 2N2222 transistor has a maximum voltagerating (BVceo) of 30 volts. Some electronic flashunits (especially non-computing types) may havehigher voltages at their trigger terminals.

5

speleanics 9v. III no. 1 Winter.Sprlng 1987.88

RECENT DEVELOPMENTS II SUPERCONDUCTIVITY RESEARCH

by Luther Stroud

Researchers have learned more this year than inthe entire 75-year history of superconductors.Once only a laboratory curiosity, recent discover-ies are making the widespread application ofsuperconductors possible.

Most metals become more conductive with lowertemperature. In 1911, the Nobel Prize- winningDutch physicist Kamerlingh Dnnes discovered thatcommon metals like lead or mercury, when cooled tothe temperature of 1iquid hel i um (-4590F) lost allelectrical resistance. This phenomenon fascinatedscientists, but the cost of maintaining such a lowtemperature, and the extreme brittleness of thesupercooled materials showed no practical uses.Other scientists experimented with combinations ofrare-metal alloys that become superconductive at -4280F but still require liquid helium coolant. In1953, an alloy of germanium and niobium became theindustry standard, with a superconductive transi-tion at -4180F. Because of the extreme cold andexpense of liquid helium ($11.00 per gallon) theuse of superconductors was limited to high-leveltechnical research equipment.

In February 1986, Alex Muller and George Bednorzof )BM produced a new class of superconductingmaterials, made of ceramic metal ox ides that havea transition temperature of -390 Fahrenheit. Thisbreakthrough began a frenzy of activity worldwide.Scientists have defined a new classification ofmaterials that are non-conductors of electricityat room temperature but become perfect conductorswhen cooled below the transition temperature. Therace is on worldwide to find materials that aresuperconductive at higher and higher temperatures.The ultimate goal is to find a practical materialthat is superconductive at room temperature orhigher. In February, 1987 Dr. Paul C.W. Chu of theUniversity of Houston announced his discovery of anew group of metallic oxide ceramics that becomesuperconductors at practical temperatures. Theyttrium barium copper oxide ceramic materialbecomes superconductive at -2840F, well above the-3200F temperature of liquid nitrogen (22 centsper gallon).

The class of superconductors is not withoutnew

References----------

1. Editorialductors. "p. 17.

staff, "The Search for Supercon-Elektor Electronics, September 1987,

2.

3.

Editorial staff, "ToshibaTapes of Superconductor."tralia, August 1987 p. 36.

Sienkiewicz, J. "Superconductivity at RecordHigh Temperatures." Hands-On Electronics,November 1987 p.31.

Prod uces Wires andElectronics Aus-

4. Rowe, Jim. "Superconductors: The Heat is On."Electronics Australia, July 1987 pp. 10-13.

problems, one of which is how to form the brittleceramic material into wire. One method suggestedis to pack a metal tube with crystals of thematerial and draw it into a fine wire. The ArgonneNational Laboratory has a contract with the U.S.Department of Energy to study the problem. Anothermethod pioneered by IBM involves spraying a thincoating of the ceramic over the surface wires.With the Nobel Prize and patents worth millions ofdollars, scientists are somewhat reluctant toshare information about individual discoveries,which slows the progress of superconductorresearch.

Superconductors can make possible inexpensive,practical and powerful electric cars. The ArgonneLaboratories announced last month their successwith an electric motor made with superconductingmaterials. Superconducting power distributionlines would be twenty percent more efficient than.existing power 1ines. Computers can be madefaster, smaller and more powerful withsuperconducting components. Superconductingappliances that will use far less power are alsopossible. Superconductors may also hold the key toa much more practical propulsion system forspacecraft based on magnetic attraction/repulsionof the natural planetary magnetic field. Small andportable CAT(computer aided tomography) scannersof much lower cost with improved functions arealso possible with the new superconductingmaterials. Currently, CATscanners are costly andimmovable due to the need for liquid heliumcool ant.

It will be a few years before the technicalproblems are worked out and superconductors getinto the consumer marketplace. Superconductors areapparently not a passing fad, but a new,unexplored science that will have major impact onindustry and consumers. Cave explorers wIllbenefit with less power-hungry electronic devicesand possibly very small electric generators withlarge power output.

Advances are occurring daily inresearch. The inventor's dreammotion is close at hand.

supercond uctorof perpetual

5. Maranto,Reality. "

Gina. "Superconductivity: Hype vs.Discover, August 1987 pp. 23-32.

6. Editorial staff, "The History of Superconduct-ivity," Superconductor Application AssociationNewsletter, August/~eptemoer 1~81 p. ~.

[Microwave System News & Communicationsogy, ~eDrua~s-TP7 ~4) reports tnatconductor which works up to SOOoK(2270C)produced at Georgia Tech.] --ed

Technol-a super-has been

6

speleonics 9v. III no. 1 ~inter-Spring 1987-88

A CAVE RADIO IN THE FIELD - SUMMER 1987

by Ian Drummond

The ASS radio was well used this summer.projects were planned, of which three werecessfully carried through.

Foursuc-

The first project was the one which fell-through,but the preparations for it helped in ~he successof the others. This project was the connection ofNita Nanta and San Agustin in the Huautla area ofMexico. The two caves come very close together ata huge boulder-choke. All efforts to connect thecaves at this point had failed and it was feltthat a distance and direction, obtained by gettingcave-radios to both sides of the choke, would helpin passing this obstacle in the ISO-foot widepassage. In preparation, the procedures and form-ulae were worked out for locating a transmitter bytriangulation from a surveyed base-line. Whenexpressed in the right form, these formul ae aresimple enough to be readily evaluated in the caveusing a calculator with sine functions. (Publishedprocedures for position-finding assume the pointdirectly over the transmitter can be reached bythe receiver operator).

The second piece of preparation was to make two 13metre square antennas from a single turn of 2-conductor 1.024 mm(18 AWG)wire. The objectivewas to obtain 2-way voice contact to the surface700 meters above, to support the complex logisticsin having an underground camp for several weekswith parties diving, surveying, exploring, andmoving supplies. The size of 13 m was initiallychosen as the largest size which would fit in myback-garden so I could test it at home. Subsequentcalculations suggested that the size was adequateto give speech communication to a depth of over1000 m but this remains untested.

The Mexico trip was cancelled when the diving teammade the connection via a 10 m sump, to make theSistema Huautla the third deepest in the world atapproximately 1370 m.

The cancellation left me with 2 weeks spare vaca-tion and an itch to tryout the new equipment andmethods. The chance came at the Speleofest held inthe Crowsnest Pass area of the southern CanadianRocky Mountains. Yorkshire Pot is the third deep-est cave in Canada at 384 m. The entrance is at7,800 feet on the British Columbia side of theGreat Divide. A series of six pits drop to 620feet, where the cave enters a phreatic roller-coaster. At the far end of this series in alittle-visited side passage, an extension had beenfound which contained pack-rat scat. An opportun-ity existed to check the accuracy of the surveyand, perhaps, to find another entrance to theremote lower sections of the cave.

The radio was taken underground, the party stop-ping at the bottom of the pits to talk to the

surface 620 feet above. Clear 2-way communicationwas established, confirming that the equipment wasfunctioning, and the party progressed on schedule.It was also useful to know that in the case of arescue, communications could be provided up anddown this difficult section of cave. While theunderground party cont inued to the rendezvous, thesurface party surveyed up, over the ridge intoAlberta. As expected, the null-point above thetransmitter was under a cliff and not accessible.However, the triangulation method was used suc-cessfully to find the location of the transmitter.It was 95m into the cliff and 140m deep, with nochance of an entrance here, but it did provide aclosed loop for the surveyors to use in checkingthe accuracy of the survey. Voice contact wasmade, and the underground party agreed to continueto the bottom of the cave for another location.Unfortunately, at the lower site no contact wasmade. The surface team was assaulted by a sleetstorm at the critical time. Possible reasons forthe missed contact are that water got in the"works," that the higher electrical noise presentduring the storm obscured the signal, or that thesurface crew were too far from the null (and notwilling to search vigorously on difficult groundin the storm). All was not lost, as several newholes were checked out, and one drafting entrancefound.

Enthusiasm was high enough that the following dayanother attempt was made to do the bottom loca-tion. The author abandoned the surface radio infavour of going underground for a change, but thelarge party moved rather slowly. We were able tomake voice contact with the surface crew to tellthem of our progress, but our furthest point wasnot located by the surface party.

Thus ended the radio work at the Speleofest. Weachieved a successful test of the triangulationmethod, a contribution to the survey of YorkshirePot, information on communication coverage of thecave in the event of an emergency, and a draftinglead for the diggers of the world.

The third project arrived out of the blue, aninvitation to do some location work at LechuguillaCave in Carlsbad Caverns National Park in NewMexico. The overburden at Lechuguilla is as highas 4DD m, so I knew that the standard D.7 m anten-nas would not reach this depth. In addition, theEM noise in the area could be higher than in theCanadian Rockies, being nearer the tropics withtheir high frequency of thunderstorms. I feltthese problems could be overcome by the 13 mantennas, but I was not sure if the magnetic fieldwould remain "well-behaved" at these depths. (SeeMagnetic Moments #5 in Speleonics 7 for a dis-cussion of the Phase Problem). In short, I wasconfident that I would hear and talk to the

7

underground unit, but I might not be able to tellwhere it was from the surface.

The first day at Carlsbad we decided to check theperformance of the units, using the theodolitesurvey of Carlsbad Cavern itself. One radio wasta ken in to The Left Tunn el to the Bell Cord Roomand The Lake of the Clouds, while the other wasused to do locations on the surface. Upon turning-on the surface unit I thought I had gone to NewMexico for nought; the noise was overwhelming.Then at 5.00pm the noise vanished as the ParkService turned off the visitors' radio system, onechannel of which operates at 115 kHz, right at thecave-rad io frequency! We were able to do twolocations, tying the null-point to a Park's surveymonument nearby. At 230 m depth (750') the errorwas 7.6 m or 3% of the depth. At the Lake of theClouds (depth 335 m or 1100') we had to use the 13m antenna on the surface to communicate with the0.7 m antenna underground. We had clear 2-wayspeech but could not do a location as the 13 mantenna cannot be rotated.

The next day we did 4 locations along the mainLechuguilla Cave passage at depths up to 210 m,and surveyed the null-points back to the entrancedatum. A field calculation showed the first threepoints to agree well, but the fourth to be wayoff. Therefore the next day was spent in the caveresurveying part of the cave. The survey wascorrect, so on the third day the cave radio wastaken back underground. A fifth point intermed-iate between the last good point and the trouble-some one was done. The problem point was thenrepeated but using the triangulation method.

The purpose here was to sample the magnetic fieldover a large area to see if it was well-behaved,that is, to see if it did indeed d iv erge symmetr i-cally from the null-point. Plotting the datashowed that the field was badly distorted. More-over, since the intermediate point only 110'm awayin the cave was not affected, the cause of theproblem must be close to the underground antenna.The most probable cause would seem to be heavymineralization of a cross-rift right at the siteof the troublesome point.

One other observation of interest was that at thepoints which were located without problems, thesharpness of the nulls obtained by rotating theantenna varied with the orientation of the axis ofthe antenna. The null was much clearer when theplane of the antenna was oriented at right anglesto the cave passage than when it was parallel tothe passage. Thus, the precision of the locationon the surface was much better along the passagethan at right angles to it.

In summary, the experience at Lechuguilla Caveconfirmed the wisdom of performing a series oflocations along the cave to provide a control gridfor the survey, rather than relying on one singlepoint at the far end of the cave to check the

~leonics 9v. III no. 1 ~inter-Sprlng 1987-88

survey. Also, it was nice to have confirmationthat those 13 m antennas really put out the sig-nals. It was just like talking on the telephone at335 m depth!

The final cave-radio trip this summer was to Van-couver Island, to Thanksgiving Cave in the Tahsisregion. The highest point of the cave is at thebase of a shaft estimated to be 60 m high. If anupper entrance to this feature could be found, thecave would move from fourth to second deepest inCanada (current depth is 356 m). Following a now-fami1 iar pattern, the underground party started,pausing every 40 minutes or so to allow a surfacelocation to be done. Interestingly, there was astrong interference present, a pulsed tone signalwhich could be nulled out by rotating the antennaso the plane was horizontal, or with the planevert ica1 on a bearing of 370. This is the firsttime I have met significant man-madeinterferencewith the radio other than broad-band noise intown. Fortunately, it did not hinder the trip.For voice communication, the antenna was orientedto minimize the external noise rather than tomax imize the signal from underground. And whendoing a location I was able to switch in a 1143-Hzaudio filter which cut out the interfering tonewhile allowing the signal from the undergroundunit to come through.

The surface conditions were a complete contrast toNew Mexico. There I had been able to move ireelyin any direction. In the Vancouver Island rainforest my companions looked on in amazement as I"crashed" about trying to follow a compass bearingin the thick vegetation, over a heavily erodedkarst landscape. In the end I had a "keeper" tolook after me; we were followed by a party of twowho flagged the trail so we did not become lost,and a survey party followed us all. They perhapshad the hardest job, as they could use only 10 mlegs through the bush, and indeed they only man-aged to travel ha1 f the distance to the finallocation before dark and the start of a stormwhich dumped 50 mm of rain overnight.

All told, a fine summer of projects with theradio. I think the key thing I learned is theusefulness of the radio to establish a grid over acave as part of a cave survey, rather than usingit just to establish one point on the surface(often for a potential entrance dig).

[Art from GRUTTAN,Swedish caving newsletter.]

8

speleonics 9v. III no. 1 ~inter-Spring 1987-88

MAGiETIC MOMENTS '7: ELECTROMAGIETIC NOISE - NATURAL SOURCES OF MOISE

by Ian Drummond

Previous "Magnetic Moments" have dealt with itemsaffecting the strength of the transmitted signalfrom a loop antenna. Equally important in deter-mining the performance of a cave radio system isthe electromagnetic (EM) noise present at thereceiver. The ratio of the power of the signal tothe noise power (SIN, the signal-to-noise ratio)presented to the ear of the listener determines ifthe signal can be heard and if it can be under-stood.

A pulsed tone of the type used in cave radios canbe recognized 50~ of the time at a SIN of 6 dB(1). For voice communication, much higher SINratios are required.

EM noise can originate within the radio receiver,or it can be external in origin. The externalnoise can be further classified into man-made andnatural noise. Man-made sources include deliber-ate transmissions such as navigation systems andbroadcasts, and incidental RF emissions frommotors, electric fences, power systems and myriadother sources. The incidental man-made noise canbe very intense in areas of high activity butfortunately it is often (1 ike cave rad ios!) verylocal in nature and the intensity drops rapidly,away from urban or industrial areas.

In the rrequency range of cave radios (2 - 200kHz), atmospheric noise is a very important factorand the predominant source is 1 ightning fromthunderstorms. The storms need not be local; theEM energy propagates over thousands of kilometers.People are suitably impressed when I tell themt~at the performance of my cave radio is limitedby thunderstorms in the tropics, and it may betrue!

The best general source of information on naturalnoise seems to be CCIR Report #322, Geneva, 1963.While I have not seen the report itself, I havefound a set of 24 world noise-contour maps inSaveskie's book (2), and further good informationon using this data in a reference book publishedby Sam s (3).

Noise levels vary with time of day and season ofthe year. Therefore the day is split into 6 four-hour periods and the year is divided into the fourseasons, giving a total of 24 time periods, eachwith a map and two associated graphs. An exampleof one map is shown here for the summer periodbetween noon and 4:00 pm.

The procedure to use these maps and graphs isfollows:

1) Find your location on the map and read thenearest contour line. Alberta is at 550N,1150W. The val ue is 40 dB.

2) Go to the graph associated with eachLocate the frequency of interest (115and find its intersection with themarked "40.. Read the Y-axis value ofdB above kT ob).

Convert this value to the magneticstrength using the following formula:

map.kHz)line

F (95

field3)

Hn .. F + 20 log10 f(MHz) - 117.0

Hn = RMS noise field strength in a 1kHzbandwidth in decibels above 1 microA/m

F .. noise value in decibels above kTobf .. frequency in megahertz

In this example Hn .. -41dB(lmicroA/m).

4) The field strength must then be adjusted forthe desired bandwidth using the formula:

where

H .. Hn + 10log10(bandwidtMkHz»

For the ASS voice radio, the bandwidth is 1.5 kHz,so H .. -39dBOmicroA/m).

5) Finally, the field strength can be expressedin microA/m using the conversion:

H(m1croA/m) .. 10(H/20)

In this example the noise field strength ism icroamps/metre.

0.011

The remaining graph associated with each noise map(which is not shown here) gives the standarddeviation of the RMS noise value., and the ratioof the first and ninth decile to the RMS value.

Knowing the atmospheric noise at a location, themaximum range of a cave radio can be estimated.If a signal-to-noise ratio of 10 dB is required atthe receiver and the atmospheric noise is -39dB(luA/m), then the signal must be -29dB or0.035ua/m.

The antenna used normally with the ASS cave radio(O.~ m square) has a magnetic moment (NIA) of 11A'm.

As noted in Magnetic Moments !!'H .. MIA. G I 2 pi d3

where dfactor.

is the range, and G is the attenuation

as

As G is a function of d, exact solution of thisequation is not easy (or necessary). Assuming Gis 0.3 (corresponding to 3 skin-depths), then d isapproximately 240 metres.

The ASS radio has achieved voice communication atdepths of over 200m, with these antennas, in thesummer in Alberta, suggesting that there are nomajor shortcomings in the receiver. Also suggest-ing that there will not be any more dramaticincreases in range through refinements in thecurrent SSB equipment operating at these frequen-c ies.

References:

0) R.J.Urick, Principles ofeng ineers. quoted inIC8907, Post-disaster1975.

underwater sound forUS Bureau of minesSurvival & Rescue.

(2 ) P.N.Saveskie, Radio Propagation Handbook, TabBooks, Blue Ridge Summit, PA 17214, USA.

Reference Date for Engineers, 7th ed. H.W.Sams & Co. (Macmillan & Co), Indianapolis, IN46268, USA.

(3)

9

180

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120. 90° 60° 30° 0° 30°WEST EAST

90"60°

Almosphc:ric noise levels in nonhern and southern hemisphc:res. summer. I ~00-1600 hours local lime. The maps showthe expected values of Fa al I MHz. in decibels above kTuB. (From CCIR Rcport 322. 10th Ph'l/ary AssL'IIl"I.\'. GCI/(','a: 1963.)

Variation of radio noise with frequency. for data given in Fig, 2 Ic:gend. (From CCIR Report 322. 10th Plenar" Assemblv.Genna: 1963.)

. .

10

speleonics 9v. III no. 1 Winter-Spring 1987-88

BATTERY DATE-CODES

(adapted from article by Stanley F. Quayle on UUCP computer newsgroup rec.aviation)

On Mallory Duracell(tm) packages, the date ofmanufacture is marked in a code like "7DXXX,. inthe upper-right corner of the back of the" card,for the ones mounted on cards. The first charac-ter is the last digit of the year. The nextcharacter is the month, where A = January, BFebruary, etc. The remaining characters are abatch number or something. The code above isApril 1987.

BEWARE-- Duracell is pushing their new dated pack-age. The advertising says that the cells keep upto 2 years on the shelf, but the date on the front(that is easily readable) is about 2-1/2 yearsfrom the date of manufacture. [New Mallorypackages claim 3-year shelf life; we do not knowtheir testing criteria. --ed]

The date code on the bottoms of Radio Shack bat-teries (regular and alka1 ine) is obvious, such as.0786" (July 1986).

Otherwise, you can tell old merchandise by seeingwhich packages have old or expired offers (freeflashlights, rebates, etc.). You can also get ahint from the store's sticker. Many stores datetheir stock with a code like the Radio Shack one(a local store uses 8607 as a variation).

Radio Shack's "Free Battery Card" entitles you

one free battery per month (and you can have LOTSof cards). The batteries don't last long, but theprice is right.

Cavers obviously should avoid batteries of uncer-tain age (Spe1eohucksters take note!). A survey oflocal stores the week after Christmas, 1987,found most batteries with readable dates to beless than one year old; a few 1985 and 1986 dateswere found mixed with newer packages.

Military batteries are clearly marked with date ofmanufacture but are often outdated when theybecome available as surplus.

-=-:-=-=-=-=-=-=-:-:-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

to

Kodak batteries have obvious dates stamped ontheir bottoms. Panasonic(tm) batteries (fromJapan) have obvious year-month date codes, and aresaid to have exceptionally high capacity. Pana-sonic cells in the above survey averaged slightlyolder than domestic brands. Eveready(tm) and 'Ray-O-Vac(tm) batteries sometimes bear 2-characternumeric and alphabetic codes, respectively. Any-one knowing the keys to these and other manufac-turers' date-codes~ please write. (Surely a fewDC-area cavers work for NSA. : -) We a1so need alist of ampere-hour capacities of primary cells,by size and manufacturer. --ed

MORSE CODE APTITUDE TEST

Frank Reid, W9MKV

Do you want a ham (amateur radio) license but fearthe Morse code requirement?

Aptitude testing was an important developmentduring World War II; the military needed greatnumbers of pilots, rad io operators, etc.. butcould not afford to waste time and manpower at-tempting to train unsuitable people.

The aptitude test for Morse code was very simple:Code was sent so slowly that the people beingtested could write-down individual dots and dash-es. Those who could tell the difference between adot and a dash passed the test, and learned Morsecode with little difficulty. It was noted thatpeople with musical backgrounds ALWAYS passed, andbecame especially good code operators.

Oral history source: Richard Blenz (NSS 5671LF),Cp1, 100th Bombardment Group, Thorp Abbots AirBase, Diss, England, 1944. Dick Blenz, now a caveowner, was an airborne radar and ECMtechnician.

RESOURCES

Antique Wireless Association

AWA is a national organization for collectors ofantique radio equipment, "devoted to research anddocumentation of the history of wireless communi-cations." There are local chapters, and regionalswap-meets similar to hamfests. AWAmaintains afree museum in East Bloomfield, New York. The AWAJournal, The Old Timer's Bulletin, is publishedapproximately TOUr tlmes per year and is availableonly through association membership.

Subscription address: Joyce PeckhamBox .E"Breesport, NY 14816

Membership: $10.00/year, $12 overseas

HeaUh ResearchBox 70Mokelumne Hill, CA 95245

Psychoceramic pub1ications-- UFO's, numerology,Bermuda Triangle, Loch Ness Monster, etc. Weinclude this resource because of the Nikola Tes1aliterature listed in the catalog.

11

THE MINI-MAGlITEt8 AND VARIANTS:

The waterproof, machined-aluminum "Mini-Maglite"flashlight i$ very popular among cavers and thegeneral public. Its durability, small size andsurprising brightness make it an excellent sec-ondary light source for caving. The light isturned on by unscrewing the head about 1/8 turn;further counterclockwise rotation focuses thebeam. There are no fall-apart problems like thoseof flashlights which turn-on by tightening theheadpiece.

Manufacturer:Length:Diameter:

(barrel)( head)(reflector)

Price:

Mag Instrument, Ontario, California5.75" (147 mm)

0.71" (18 mm)1.00" (25.4 mm)0.75" (18.1 nm)$10 - $15

Bulb tests: (New bulb with two freshbrand alkaline AA-cells under load.)

Duracell-

Current:Diameter:Length:Base:

320 mA @ 2.6 V0.117" (3.0 nm)0.375" (7.5 mm) [not including pins]Wires, 0.020" dia., 0.050" apart,0.25" long. [0.05, 0.13, 0.65 mm]

resistance increases asA used bulb took 300 mA;filament metal evaporates.

Bulb life-rating is "4 to 5 sets of batteries."Some ads say that the bulbs are argon-filled. Onepackage of two replacement bulbs ($2.39) waslabeled "vacuum bulbs," which could explain theirnoticeable blackening after only one hour of use.(Evaporated tungsten collects inside the glass.)

Alkaline cells larger than size-AA, having lowerinternal resistance, would probably burn-out thebulb, however, it works well with a single lead-acid "gel-cell" (2.2 v). A 5-ampere-hour gel-cells hou ld prov ide about 15 hours of 1ight, andgreatly increased bulb life due to lower voltage.

The tiny bulb could be built into a caving helmet.The wire-base makes such improvisations easy.

Errors in measuring the low voltages and highcurrents of flashlight bulbs may be appreciableunless metering circuits are carefully d~signed;I used a high-impedance digital voltmeter (BeckmanDM73) to measure voltage directly at the bulbbase. The same voltmeter was used to test voltagedrop (0.006 v) across the ammeter (Beckman DM25Ldigital multimeter on 10-amp de range).

Accessory kit: The optional Mini-Maglite acces-sory kit contains a short lanyard, metal pocket-clip, colored filters, and a hexagonal rubberlens-guard/filter-holder which prevents rollingwhen the light is placed on a flat surface. Therubber guard is the only accessory useful tocavers; I installed mine along with the clearfilter to protect the lens.

and KEY-MATE. These variants useTheir two-pin wire-base bulbs are

identifiable by a colored ring or plas-

MUII-MUIlMAGAAA- c e 11 s .somet imes

v. III no. 1speleonics 9

Uinter'Sprlng 1987-88

ELECTRICAL TESTS AND CAVER MODIFICATIONS

Frank Reid

tic sleeve around the base. The tiny Key-Mate isa good addition to an emergency kit or, as itsname implies, a key ring.

Bulb Batt CurrentColor

Identifier--------------------------------------------------MinimagMini-MinimagKey-Mate

2-AA2 -AAAl-AAA

320 mA170220

(none)bluered

HorizontalMay 1986,cavers tonecks:

Flashlight lanyard. In CRF Newsletter,Rick Olson suggests a Defter way forcarry small flashlights around their

"...Even with the shortest cord which will fitover your head, the flashlight winds up betweenthe floor and your sternum in a belly crawl. Afriend, Pat Porter, suggested that the light besuspended horizontally instead of vertically, likea St. Bernard's cask of brandy. This is easilyaccomplished by running the cord through a tightrubber band near the front of the flashlight. Amuch longer cord can be used if a loop is pushedthrough a small "Barrel-Loc" [spring-loaded slid-ing plastic cord-lock, as used on drawstrings].The light can be raised high when not needed, andlowered as desired. A knot will prevent the cordpulling out of the Barrel-Loc again. The lanyardcan also carry a folding hand-lens, small compass,or a tip reamer..."

I used a plastic cable-tie, and a continuous loopso that the flashlight will not be lost if anattachment point breaks.

Never wear a cord around the neck during anycli.bing operation-- leek cords caught on projec-tions during falls have resulted in injury anddeath. The original configuration, using a rubberband for the forward attachment point, allows thelanyard to break free if caught.

Make the lanyard long enough to allow a heav-ily-clothed person to hang the lanyard over theshoulder and secure the light tightly in the oppo-site armpit, for hands-free forward illumination.This configuration is almost as convenient as ahead-mounted light; right-handed people shouldhold the light under the left arm so that theworking arm is less likely ~lock the beam.

Horizontal-suspension lanyard holds flashlightthree ways. "Mini-Maglite" balances with heavyhead-end tilted slightly downward.

12

Agen cy State MHz------------------ -----------------------Badlands NP SD 169.40 170. 05 170.10BIA, tribal police SO 39.10 39.16 39.24

39.28 39.32 othersDevi l' s Tower NM WY 169.40 170.05Jewel Cave NM SO 170.05Mount Ruslvnore NM SO 170.05NPS, Black Hills SO 169.40U.S. Forest Serv SD 169.95Wind Cave NP SO 170. 05 170. 90

speleonics 9v. III no. 1 ~inter.Spring 1987-88

ELECTRONIC HYPOTHERMIA ALARMFrom BCRA Transactions, December 1975,in TnelTnderground ~xpress, vol. 2,197or:-;:: pages.

reprinted12 (Spring

An electronic device the size of a matchboxwhich can be built for only a few dollars... willenable even a rank novice to know when a hypo-thermia victim can be moved under his own power.While the patient may still be mobile, his bodytemperature may have fallen to the point wheremovement may cause much more rapid and perhapsfatal deterioration by using up his last stores ofenergy... The device lights up when the patient'smouth temperature (a reflection of his core temp-erature) falls below 350C. At that point, thepatient should no longer be moved under his ownpower.. .

A thermistor balances a bridge circuit at 950F050C). A voltage comparator (LM308) 1ights a redLED if the temperature falls below that point.For waterproof operation, a magnetic reed switchis used to turn on the battery. One magnet andthe relay are mounted inside the case, anothermagnet outside in a spring clip, so that themagnetic fields cancel in the vicinity of therelay. The device is then turned on (circuitclosed) by removing the exterior magnet. Ingen-ious! The magnet is then clipped to the patientusing the spring clip.

A CONTINUOUSLY VARIABLE LIGHT FOR CAVINGby Bill Varnedoe, Huntsville Grotto News, vol. XV,lID (Oct. 1974). z pages. --

"liow often we've wished we could vary the intens-ity of our caving light, up to peer into a deeppit, or down to stretch the life of a battery...We've been forced to. exchange bulbs of lower andhigher current rating. This is an awkward and notvery satisfactory solution There simply are notvery many bulbs of a specific voltage to form aseries, besides the bother of disassembly of thehead1amp, etc."

The dinrner circuit is a switching-type dinrner withabout 90% efficiency. The relatively simple cir-cuit uses four transistors. The author givescredit for the design to Mike Cox (NSS 14031) ofIndianapo1 is.

LAMP DIMMER MEASUREDby Bill Varnedoe, Huntsville Grotto News, vol. XV,III (Nov. 1974) j pages. -This companion article to the one mentioneddescribes testing of the variable lamp,contains a graph of cand1epower vs. current.

ab oveand

DIMMER CIRCUIT, MODIFIEDby Bnl Varnedoe, Huntsville Grotto News, vol.XVIII II (Jan. 1977). to pages.-

A CD4002AE CMOS chip replaces two transistorsthis redesign of the circuit of the Decemberarticle, lowering the parts count somewhat.

in'74

Above four articles contributed by NSSB111 Torode.

Librarian

IN REVIEW

CONSTANT VOLTAGE SDURCE FOR BATTERY OPERATED LAMPSE1ektor Electronics (English-language German e1ec-tronlCS magazlne) ~ebruary 1984. 3 pages.

This novel switching-regulator design can be usedas a lamp dinrner but its primary purpose is tokeep the power supplied to the lamp, and thereforethe light intensity, virtually constant over thenormal life of the battery.

"Unfortunately, dry batteries have a serious draw-back: their output voltage falls linearly withtime so that at the beginning of their life thelamp burns brightly, while long before they areexhausted, the lamp begins to resemble a glowworm! Not only is this highly undesirable from asafety point of view, but it also makes for loweffic iency.. ."

The circuit contains four operational amplifiers(a single LM339) and two transistors. It containsa voltage reference; its main purpose is regula-tion, though it can also be used as a dinrner.

[Voltage regulators are recommended for someapplications of the new rechargeable lithium cells(referenced in SPELEONICS 8), which change voltagerather drastically during discharge.] --ed.

Contributed by Luther Stroud and Peter Ludwig.

RADIO COMMUNICATION THROUGH ROCKby B.A. Austin, Electronics & Wireless World,Sept. 1987 p. 943. j pages. - -Underground rad ioin South African mines is highlydeveloped. The author has designed SSB systemsoperating between 100 kHz and 1.1 MHz. Ruggedizedmine transceivers use loop antennas built into theshoulder strap. Ian DrU880nd is now correspondingwith the author.

Contributed by Bo Lenander and Luther Stroud.

Copies of the above articles are available fromFrank Reid for SASE. One-ounce postage is goodfor 5 pages.

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

FREQUENCIES OF INTEREST: 1988 NSS CONVENTION

These are VHF FM frequencies of government agen-cies at some of the interesting places in and nearthe Black Hills region, for your scanning pleasureduring the NSS Convention at Hot Springs, SouthDakota, June 27 - July 1.

Sources: cavers, POPULAR COMMUNICATIONS magazineJanuary 1987, February, 1987.

13

speleonics 9v. III no. 1 Winter-SprIng 1987-88

ELECTRONIC WRISTWATCH MAKES EMERGEICY FLASHllGIT

An LCD digital watch with internal illuminatormakes a useful miniature flashlight if it can bemodified so that the lightbulb is directly exposedthrough the watch crystal.

The light is surprisingly bright, adequate foremergency repair of other cave lights and equip-ment, or read i ng maps and in str uments. Fullydark-adapted eyes require very little light.l

A watch-flashlight is always ready, but cumber-some; operation requires both hands unless thewatch is removed from the wrist. Wristwatchilluminators quickly deplete batteries, which areexpensive and sometimes difficult to replace.Watches should be used as flashlights only if noother light is available.

My Casio thermometer-watch contains a relativelylarge lithium cell which lasts 4-5 years in ordin-ary service, so seems a good candidate for modifi-cation. Some watches have separate batteries forlight and electronics.

The Casio is easy to disassemble, by removing fourscrews from the back. The electronics package canthen be removed from the case. The 1ight is thesize of a 1/10-watt resistor, has axial leads, andis beneath a layer of black plastic on the leftside of the display. 1 used a small "X-Acto"knife to carve a hole in the plastic, and to

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CALL FOR PAPERS

We need abstracts for papers to be presented atthe 1988 NSS Convention at Hot Springs, SouthDakota, June 27-July 1. NSS NEWS, February 1988(p. 43) says,"The abstracts-GeaaTTne is March 31,1988. They should be no longer than 150 words inlength. Since they will be published in the NSSBulletin after the convention, they shoud be In-tormatlve (give objectives, methods, results andconclusions) and do not refer to the presentationitself."

Send abstracts to Frank Reid (address on p. 1).Please indicate what audio-visual equipment youwi 11 need.

We also encourage informal presentationselectronics session, for which abstractsbe submitted. At this printing, a timesession has not been set.

at theneed notfor the

14

Frank Re id

scrape away a spot of paint inside the crystal tolet the light shine out. When reading the watchat night, my thumb covers the direct light.

Cas;o recommends that watches be sent to theirservice center for battery replacement in order toguarantee the waterproof seal; an O-ring under theback becomes permanently deformed and should bereplaced when the battery is changed.2

[Casio's digital-thermometer function is onlymarginally useful. There are two modes, on-wristand off-wrist. On-wrist mode is accurate only inthe absence of wind and water; it uses an addi-tional sensor on the back for body heat. Responsetime for both modes is very slow, around 20minutes.]

Tiny 1.5 and 3-volt bulbs can be salvaged fromdiscarded watches, or bought from jewelers andother sources. Experiments continue with ultra-small 1 ights for cavers: Watch bulbs could betransplanted into larger bulb bases (includingMini-Maglite(tm)) and used for long-duration emer-gency light. They are smaller and brighter thanlight-emitting diodes and could be used as compassilluminators.3 Very small emergency lights can bebuilt into caving helmets.4 A tiny bulb couldmake a helmet-light for a "Gl Joe" doll dressed asa caver, for scale in cave photography. <*:-)

References----------1. Fermi,

p. 2.T. "Nuclear Flashlights," Speleonics 6,

2. Reid, F. "Emergency Watch Repair for Cavers,"Speleonics 7, p. 3.

3. Market, R. "Lighting Up Your Suunto,"onics 6, p. 14.

4. Stuproch, J.C. "An Emergency Light System,"Georgia Underground v II II p. 10. Reprinted:Speleo Digest 1965, p. 3-82.

Spe1e-

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