speleonics 12 APRIL

19a9

"BETTER CAVING THROUGH ELECTRICAL STUFF" volume III number 4

.':1'

[photo by Harold Pruitt]

THE BRIEF COLLABORATION BETYEEN ALFRED NOBEL AND THOMAS EDISON

or

THERE IS NO NOBEL PRIZE FOR SPELEOLOGY

Sam Frushour (L) and John Hartman re-enact a technically-correct version of a cartoon from The NewYorker magazine (7 November 1988, p. 154). Antique equipment: Hurcules(tm) 50-cap blasting machineand General Electric Mazda(tm) tungsten-filament lamp. ~e cheated to preserve the bulb (from AngeloGeorge's garage sale)-- It's actually connected through a triac lamp-dimmer to the lights in thecommercial section of Cumberland Caverns, Tennessee.

Cartoon blasting machines are nitroglycerine pumps but real ones are electric generators. Therack-gear plunger spins a flywheel, and closes the circuit when it reaches the bottom of its stroke.The output can light a 115V 100-lIatt bulb for one second. Mechanical blasting-machines are beingsupplanted by compact (but less dramatic) capacitor-discharge electronic types containing dc-deconverters. The machine in the picture weighs 22 pounds (10 kg). lie don't recommend this system forcave lighting! Fortunately, product-liability lawsuits were rare in Nobel's day. On the other hand,consider the case of Coyote vs. Acme!

SPELEONICS 12Volume III, Number 4. April 1989

SPELECIIICSis pU:llished approximltely four times peryear by the COIIIIU'Iication ard Electronics Section of theNational Speleological Society (NSS). Primary interestsinclude cave radio, underground cOllllU'lication and instru-mentation, cave-rescue communications, cave lighting, andcave-related appl ications of amateur radio. NSS menber-ship is encouraged but not required.

Section menbership, which includes four issues ofSPElEONICS, is $4.00 in USAlc:..dBIMexico, 16.00 over-5888. Send subscriptions to section treasurer JoeGiddens at the address below (make checks payable toSPElEONICS). If you have a ham-radio callsign or NSSmenbership number, please include them when subscribing.

Forei gn subscripti ons can be paid in U.S. "paper"dollars in the mail; an international money-order maycost as much as the subscription. Many menbers have sentcash without problems. (No forei 9" currency, please.)

Editorship rotates among the officers. Volunteers areencouraged to guest.edit or produce an issue. A technicalsession, followed by election of officers, is an amualevent held during the NSS Convention.

C~l imentary copies of SPELEONICSare mailed to NSSoffices and sections, the u.s. Bureau of Mines, U.s.Geological Survey, and the longwave Club of America.

CONTEIITS

-._-----

THERE IS 110 IIOBEL PRIZE FOR SPElEOLOGY[cover story]

Editorial 1

IIEVS & AIiIlOUIiCEMEIiTS -Informal Spring MeetingsRegular publisher unavailable 1"Radio Pit" openedCave rescue on network TVSuper LEDs to be available at NSS Convention.Call for papers 3

AUSTRALIAII RESCUE USES CAVE RADIORon Allum 2

LETTERS.Dave Ursin, Ron Johnson 3Dave Johnson 8

Magnetic Moments #9:GROUND COIIDUCTIVITY BY ELECTRO-MAGIIETIC METHODS

Ian Drummond 4

SCIEIITIFIC CAVE LOCATION [reprint]Ph ill ngham '..".'.""""'..' 6

CAPACITIES OF PRIMARY CELLS[collected reprints] 9

SUMMARY OF THE CAVE-RESCUE TELEPHOIIE PROJECTJohn Halleck 10

PHOTOS OF LUMIIiESCEIiT CAVE MIIiERALS VAIITED 13

RESOURCES: ULTRAVIOLET LAMPS FOR MIIiERALOGY ... 14

JAPAIIESE CAVE-RADIO USED III VORLD VAR II 15

REVIEVS -Bat detector, Field telephones,BCRA CREG v.1 no.2 15

Electronic Bat-Feeder [cartoon]artist unknown 14

Art by Jay Jorden 15

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

Section officers and Speleonics staff:

Chairman (and editor ofissue 14:)

Secretary (and editorof this issue):

Ian Dr~nd627 Varsity Est.Calgary, AlbertaCANADA T3B 3C4A[IIEV ADDRESS]A

Cres. N.W.Frank Reid W9MKVP.O. Box 5283Bloomington, Indiana47407-5283W9MKVi K9IU Z: 47401

Treasurer (and editorof issue #13):

Publisher:

Joe Giddens 11510Zpo Box 891Camden, Arkansas71701

Diana E. George I190EJ1869Trevilian Waylouisville, Kentucky40205

Editorial - As we end our third volune, it is grati-fying to note that Speleonics has become self-generat-ing-- For the first time we have a backlog of articlesfran many contributors. We hope to keep the gestationperiod reasonable by pU:llishing more issues per year ifnecessary. We are experimenting with new software, hopingto enhance the print quality of future issues.

--Frank Reid

IlEUS All) A8II8DEIITS

INFORMALSPRING MEETINGS. All Speleonics readers, cav-ers, VlF/lF experimenters, and interested people areinvited to our second arnJal meeting at the DAYTCIIIIM-VEllTICII(Dayton, Ohio) at 11:00am local time on Saturday,April 29. Place: Seats (I) above main arena (the "bigroan" containing major manufacturers' displays), Southcorner behind DARA booth (to right of main entrance), toplevel. A carbide l~ will mark the spot. Show/tell,trade equipment, share information (including flea-marketlocations of interesting items) or just say hello. Bringlunch if you wish (recommended; hamfest food is awful!:.(* Freq: 147.64 14Hz, RFI permitting.

Bring cave radios and other electronics to ICEIIl1DCYSPELEOFEST (Memorial Day weekend, 26.29 May, near WhitleyCity; KY). I.. D~ fran Canada plans to attend; wemay be able to assemble all the section officers for thefi rst timet See NSS News or contact Fnnc Reid for de-tails. Freq: 146.66 Mii'ZSilTplex.

"FREED<J4 OF THE PRESS BELONGS TO HIM WHO OWNS ONE."-- St. Wysiwyg of Gdansk

Di- George, or regular publisher, has been unable toprint the last two issues of SPElEONICS due to heavyworkloads of the primary users of the press. We arepresently using facilities of higher cost and lowerqual ity.

[Conti rAJed p. 3]

1

.pel.ODic. 12v. III no. 4 Apr. 1989

AUSTRALIAN RESCUE USES CAVE RADIO

We were fortunate to have our induction radiofor the 88 Pannikin Plains Cave cave-diving expe-dition on the Nullarbor Plains, Australia when adeluge of rain caused a collapse of the cave'sentrance trapping 13 of us inside. Without thecommunications, the uncertainty of not knowingthat everyone had escaped the rock collapse andbeing able to coordinate rescue teams, the situa-tion would have been far more severe.

Although the report was not written for Spele-onics it may help add some weight to the use ofcave communications expecially when you need itmost.

Ron All\818 Riverglen DriveWindsor Gardens 5087AUSTRALIA

Strol19RD. F.

WindS preV(l.ntnz.c.~ptjon .

Erroneous rumors preceeding Ron's letter said thata British "MoleFone" had been used. Details ofRon's equipment were published in SPELEONICS4. Acondensation of Ron's report and newspaper cover-age follows. The complete articles are availablefrom Frank Reid for SASE.

Sunday Observer (Victoria) 4 December 1988 p. 1:

Nullarbor rescue missionCAVE-IN13 SAVED

by Paul Daley and Ken Burrowes

Rescue workers late last night freed the lastof 13 dives trapped for 24 hours by a cave-in 90metres below the Nullarbor Plain.

The divers were filming a documentary on thesystem of caverns near Cocklebiddy, near thesouth-western tip of the plain, when a suddensevere storm dislodged rocks blocking the caveentrance.

Police spokesman Inspector David Tree said therescue was carried out under extremely dangerousconditions. "It was raining and freezing cold andwe were worried there would be another cave-in atany time," he said.

The 10 men and three women were trapped when afreak "hurricane" blocked their only exit from thecave at about 6.30pm (local time) on Friday.

The group of 18 was made up of two Americans,one Briton, six from Sydney, eight from Adelaide

and one from the Gold Coast. Members of the group,described as "some of the most experienced cave-diving people in the world," were removing equip-ment after finishing a three-week expedition...

Two of the group scrambled to the surface asrocks began to fill the perpendicular shaft to thecavern. They joined three team members who hadstayed outside the entrance and raised the alarm.

The trapped divers were able to communicatewith those working above the ground, using aspecially-developed radio designed to transmitthrough as much as 250 metres of rock.

The documentary crew includes people who in1983 broke the world record in cave diving dist-ance in the same system of caves...

THE PANNIKINS PLAINS CAVE DIVING EXPEDITION 1988Incident Report

by Ron Allum

The Pannikins Plains Cave Diving Expedition1988 experienced an exceptionally strong weatheroccurrence only minutes after the final cave diveof a very successful expedition. Cyclonic-forcewinds lashed the camp and 100mm of rain was dumpedin less than 20 minutes causing extensive damage,the result of which posed serious threat to thelives of some expedition members. The entrance tothe cave, being the most low-lying area for sev'eral kilometres, became the drain for the floodwaters. A 360-degree waterfall poured into thecave entrance.

...Ironically this was the expedition's finaldive, irrespective of this occurrence. From "Con-corde Landing" (an inner air space used as anadvanced base) they brought with them the lastremaining equipment, leftover food, water (cavewater is to saline to drink), warm clothing, bed-ding, communications unit, radio direction finderetc.

-RO.F HAZARD-l<XXItI"9the position of Conc.ol"de Landing-under the only ~ign of clvilis-ahon on

tM, Nullarbor De.stu-t.

2

Thirteen people grouped together at the lakeside to witness this phenomenal process of nature.Concern then existed for the safety of the remain-ing expedition members, however to attempt toascend the subsiding rockpile to go to their aidwould not be not 'bravado' but 'suicidal'. A 240vpower cable, telephone line and a copper air hoselinking this chamber with the surface were severedduring the collapse.

The cave dwellers prepared for the inevitable,although safe beneath the solid cave roof. A stocktake of our provisions was made, warm clothing andbedding was shared as evenly as possible, food andwater supplies if rationed would last severaldays, cave lights were also conserved...

8am, 12 noon, 4pm and 8pm had been the routinecommunications schedules when we had divers atConcorde Landing. This equipment now with us, the30m-diameter aerial was laid out in the lake cham-ber, hoping that the surface party would connectthe topside equipment to an aerial which alreadylay on the surface directly overhead. There was noschedule for... communication from where we were.Fortunately, the surface had taken the initiativeto set up their equipment and at 9am, as if byschedule, the first voices from the surface werereceived. 'Surface to Chamber, over'. The firsttransmission from the cave responded 'Yes surfacethis is chamber, there are 13 of us; who is on thesurface? over'. Surface replies and lists 5 names,

spel.onic. 12v. III no. 4 Apr. 1989

everybody was accounted for and were safe. Thesolemn atmosphere instantly disappeared and thetask of assessing the situation started. Curiosityat times took over and graphic descriptions of thestorm and the rock fall were also exchanged.

On the surface the camp was flattened and verywet. At 10pm a contact list of relatives wastransmitted to the surface. By now it was realisedthat we could be here for days... Thoughts ofusing the RDF to locate the most suitable positionto drill a hole were discussed. At 11pm, apartfrom receiving an update of the rescue organiza-tion happening above we were content to keep awayfrom the still collapsing rockpile, at least fortonight. The next communications schedule was madefor 7am.

Progressive assessments were made through themorning, coordinating movement via the communica-tion system. Eventually common ground was sightedand a plan for the first person to exit wasmade. The first person was out at 4pm, 24 hoursafter the first rainfall. The other returned,carrying a pack of warm clothing brought in by therescuers in case there may be some inadvertentdelay for the remainder to exit.

Progress of the exit was checked every 30 min-utes using the communication system. The finalcommunication was at 7.15pm, the last person wason the surface at 7.45pm. The cave was clear ofall rescuers at 8.15pm.

[cont i nued from p. 1]-=-=-:-:-:-=-:-:-=-:-=-:-:-:-=-=-=-=-:-:-=-:-=-:-:-=-=-:-=-=-=-:-:-:-=-=-=-:-:-:-:-=-=-:-:-=-=-:-:-:-:-:-=-=

LETTERS

"RADIO PIT- CI'EJIED. DougMedville's article inDC SDeleoQraDh (JaBJary 1988) describes digging andblasting a new entrance into a remote area of the Friar'sHole! Canadian Hole cave system in West Virginia, basedLpOn radiolocations which I., D~ made in 1983. Thenew entrance began at an air-blowing pit 10 feet from theradiolocation. "Four years later we got in. That's thebottom line. We worked like hell and literally fought foralmost every foot of the way until the final connectionwas made on July 18, 1987." An account of the actualconnection appears in The Canadian £!m, Spring 1988.

CAVE IESCIEell IIIE1\DICTV. Indiana cavers re-enacteda 1985 cave rescue for CBSTelevision, to be aired some-time in Mayas part of a 3-part series entitled "911Rescue." The cave se9llertt wiII be 10-15 minutes long.

SIFERLEOs TO BE AVAILABlE AT IISS aJIVEIITleIIJohn Halleck has experimented with the new "super bright"light-emitting dicxles for use as emergency cave lights,using Radio Shack's 2000-millicandela units (normal LEDsare 200-500 mcd). Hewlett-Packard plans to market newLEOs in June, with outputs up to 10,000 mcd. John hasarranged to buy a quantity of these, and plans to makethem avai lable at the convention.

CALL Fat PAPERS OUr amusl technical session andsection meeting at the NSS convention (July 31-August 4,Sewanee, Tennessee) wiII feature formal and informalpresentations, the main difference being that abstractsof the formal papers are published in the ~ Bulletin.Send abstracts to Fr8rit Reid (address p. 1) as soon aspossible; indicate what audio-visual equipnent you wiIIneed. The abstract deadl ine and session date have not yetbeen annoU"ICed (see forthcoming issues of NSS ~).

OUr rescue organization needs cave radios! Has anyoneprcxluced a single-sided printed circuit layout for RayCole's "Organ Cave Radio" [Speleonics 3]1

Dave Ursin

953 East 400 SouthKaysville, Utah 84037

II GHT WAY, IottCJIG WAY. TEXAS WAY!

Dear Frank,I would like to jump into the controversy over which

way to wire a "standard" two-pin DC connector for radiosand other accessori es ("Communi cations Standard #1. 0",Speleonics 2; Letter from Duke McMullan NSGAX, Speleonics11). Basically, y'all picked the wrong kind of connector!

A better choice than Cinch-Jones plugs (or the RadioShack attempted copy) would be the automotive-type male!female connection pictured here.

P08iti.e(inaulated) P08iti.8 (doean't ..tter)

J !~~~Volta.e SOURCE LOAD De.ice (radio, etc.)

These are available widely in most auto-parts stores,and wiring polarity is intuitively dictated by safetyconsiderationl through our negative-ground universe(I've heard tell of positive- ground automobiles butI've never seen one) as follows:

The voltage SOURCE connector (i.e., battery, powersupply) has positive on the rubber-covered (female)

[continued p. 8]

3

.paleoDicD 12v. III no. 4 Apr. 1989

Magnetic Moments no. 9:GROUND CONDUCTIVITYBY ELECTRO-MAGNETIC(EM) METHODS

Ian Drummond

Since the editorial in Speleonics 8 aboutsearching for caves by measuring ground conductiv-ity, I have had some correspondence with caversdoing just that. Also, the second newsletter ofthe British Cave Research Assoc. (BCRA) cave radiogroup has an articLe on conductivity (or resistiv-ity) techniques [reprinted in this issue; Spele-onics 11, p.1 has an announcement on the BCRAnewsletter.]

Both groups were concerned with the traditionalcurrent-injection method, where an array of fourelectrodes are inserted in the ground. An elec-trical current (AC usualLy, but DC can be used) isinjected via two electrodes, and voltage is meas-ured across the other two.

As discussed in the Speleonics 8 editorial, EMmethods of measuring conductivity appear to offersome significant advantages by increasing speed ofmeasurement in the field. This issue of MagneticMoments will Look at some of the principles under-lying EM methods, and suggest a particular schemewhich Looks easy to implement with existing cave-radio equipment.

First, consider a transmitting loop lying flaton the ground (Fig 1). The primary magnetic fieldis the familiar shape shown in the figure, howeverthe current in the coiL wiLL induce eddy currentsin the conductive ground. These eddy currentswill, like those in any inductive load, be 900out-of-phase behind the current in the primarycoiL, and will give rise to a secondary magneticfield (Fig 2).

Consider then the magnetic field at a point onthe surface to one side of the transmitting loop.It consists of two components, the vertical prim-ary field, and a secondary field which has bothvertical and horizontaL components and is 900 out-of-phase with the primary field.

J.R. Wait has published equations describingthe strength of the magnetic field in those circ-umstances. (Mutual electromagnetic coupling ofloops over a homogenous ground. Geophysics, Vol.XX, no.3, July 1955, pp. 630-637)

Given this basic information, there are severalways to estimate the ground conductivity.

Most straightforwardly, using a calibratedtransmitter and a calibrated receiver, the valueof the mutual impedance can be measured from totalfield strength, to allow calculation of the con-ductivity.

Using more sophisticated equipment with aphase-locked receiver, the value of the secondaryfield only can be measured, allowing more discrim-inating estimation of the conductivity.

Both such methods (and others, for all I know)are in use in commercial equipment, as reportedfor instance, in "Geophysical Techniques for sens-ing buried wastes" Benson, Glaccum and Noel;Report EPA-600/7-84-064. US Environmental Protec-tion Agency.

Both methods are also difficult to implementwith existing cave radio equipment, therefore Ispent some time thinking abut Wait's equations tosee if his results could be adapted to use withcave radios. The following method has not beentried practically, but seems to have a lot ofpromise.

Fig. 1- The primary magnetic field around a coil.(The figure is geometrically accurate.)

--abJIY c.M_T"$,,,,...c..a1> 1/116«0"",,1)

UHI.."'. V~-y"--_n' ~'.~b,ollf1C.lt~ "'.~'D.

Fig. 2. Showing the primary and secondary magneticfields arising from a loop on the earth's surface.

The proposed method depends upon using tworeceiver-antenna orientations, and measuring theratio of the signal strength. This eliminatescalibration of the transmitter, and if the receiv-er output is linear with input signal, eliminatesreceiver calibration too.

The proposed procedure is as follows:

1) Set-up the transmitter loop with its planeexactly horizontal on the surface of the groundabove the point of interest.

2) Set-up the receiver loop at a measured distancefrom the transmitter equal to the estimateddepth of caves in the area. The loop should beset with its plane exactly horizontal, at thesame elevation as the transmitter.

3) Measure the signal strength (volts) with thetransmitter off, V(H-background), and transmit-ting continuous tone, V(H).

4

0.01

0.00.

0.G08

~O.ClO7

~~0.G08

" ~0-~F= 0-~o O.IIID<J

0-0.001

I / /

I 1/ / /I 1/ /

/ / / /1/- I}- fie- /V

I / ~./"

/ / !/ /' ./ K./

/ V /"./ ,/'/ --

/ V ./ ,/' ...-- -- I-- ~---If£. V --- ....---- - -

0.0 0.0 2.4 0.5910.2 0.0159 2.6 0.6470.4 0.0404 2.8 0.7040.6 0.0872 3.0 0.7710.8 0.151 3.2 0.8191.0 0.211 3.4 0.8661.2 0.269 3.6 0.9121.4 0.326 3.8 0.9631.6 0.383 4.0 1.0131.8 0.437 4.2 1.0672.0 0.483 4.4 1.1272.2 0.533 4.6 1.189

4) Rotate the receiver loop so the axis of theloop is horizontal and pointing directly at thetransmitting loop.

5) Measure the signal strength (volts) with thetransmitter off V(V-background), and transmit-ting continuous tone, V(V).

6) Calculate (V(V) - V(V-background» / (V(H)V(H-background» and use Graph 1 or 2 to lookupdirectly the value of the conductivity.

For those people using other values of freq-uency or inter-loop distance than given in thegraphs, I have tabulated the Voltage Ratio against"Numerical Distance" and it will be necessary tocalculate the conductivity from the formula givenat the end of the table.

I would strongly recommend when doing a trav-erse along a surface line, that readings be takenwith the two antennas aligned with the traversedirection and with the two antennas at rightangles to t~traverse direction. The reason forthis is that I feel limestone terrain will exhibitdifferent conductivity in different horizontaldirections (anisotropy). I have experienced direc.tional effects with my cave radio that I cannotexplain except by anisotropic conductivity of theground (See Speleonics 9, page 8).

This observatton applies equally to conductiv-ity surveys done by current-injection methods.

Further Work. Obviously there are a lot of prac-tical things which could be tried to see how suchan EM system would work. There is however onemajor theoretical contribution which would be veryuseful if there is a person out there who has acomputer and the necessary knowledge and skill.

The interpretation of the conductivity esti-mates is very primitive, si.ply assignment of a

CONDUCTIVITY BY CAVE RADIO115.4-

oo 0.1

\IOI.T'- IW10

0.8o.a 0.4

'peleODic. 12v. III no. 4 Apr. 1989

"bulk value" to a point in the ground ilalfwaybetween the loops at a depth equal to their separation.

It seems to me it should be possible to con-struct a numeric model so that the effect ofvarious sub-surface conditions could be tested.Chambers, joints, bedding-planes, and tubes wouldall affect the apparent conductivity measured fromthe surface in different ways. Such a model wouldalso give an estimate of the sensitivity of themethod, that is the smallest feature which mightbe detected under given conditions.

It would certainly enhance the interpretationof conductivity data.

Table 1. Numerical Distance v. Voltage Ratio

NumericalDist. Voltage Ratio

- - - - - - - - - -. - - - -. - - - - - - - - - -+- - - - - - - - - - - - - - - - - - - - - --

Conductivity (mho/m) =(ND/d)2 . .(1/f) . 1.27 x 105

where ND = Numerical Distanced = distance between loops (metres)f = frequency (Hz)

CONDUCTIVITY BY CAVE RADIO3.5-

l.a 0 0.1o.a 0.4

Fig. 3. The distance is the inter-loop distance. Voltage ratio is the ratio of measurements made withthe antenna plane vertical, axis on a radial from transmitter, over those made with the antenna planehorizontal.

5

apel_aioa 12

v. III no. 4 Apr. 1989

SCIENTIFIC CAVE LOCATION

by Phil Ingham *

Since early trials proved that earth resist-ivity methods are of great use in locating un-derground cavities within limestone masses, themethod has been used with considerable success.Whilst there are numerous variations to the equip.ment layout used to measure resistivity, they alluse the principle of a current (I) being intro-duced into the ground through electrodes, and thepotential difference (V) between two points beingmeasured with a second pair of electrodes.

The current is usually generated by batteriesin portable equipment, although some generatorsets are available. Normally the current used isalternating (AC), and this removes unwanted polar-isation effects around the electrodes. If directcurrent is used, then the polarisation effectshave to be countered, by placing the electrodes inporous pots filled with copper sulphate solution.An alternate method involves the use of a high-impedance circuit and compensatory network.

APPARENT RESISTIVITY

If a current is introduced into the groundthrough a pair of spaced electrodes and the poten-tial v across an area between them is measured,(fig 1), then the resistance can be worked out.The relationship between voltage, current andresistance is defined by Ohm's law. This statesthat V

'"IR.

FIGI

If we consider a point electrode on the surfaceof a homogenous earth, extending down for an in-finite distance and having 8 resistivity p, bythen describing a shell around it of radius r andthick~ess dr, we can say that the current passingthrough the electrode into the earth is I, thepotential difference across this shell will be

V = Ip dr/2 r2 .By integration, we obtain thedistance r, from the point, as

potential, at

V(r) = Ip/2 x 1/r .If C1 and C2 are the current electrodes and P1,

P2 are the potential electrodes and V is thepotential difference between the electrodes, thenit follows that

p = 2 x V/IG

where G = 1/C1P1 1/C1P1 1/C2P2 1/C2P2.

In actual use, P will vary when the electrodegeometry is altered or when they are moved keepingthe same configuration. That means the actualresistance will not be directly proportional to Gas on a homogenous earth. The value of p obtainedon substituting the measured R and the appropriatevalue for G, is called the Apparent Resistivity ofthe earth. This is a formal, rather artificialconcept and does not represent the general oraverage resistivity of the earth. To assess thisfigure properly, the type of configuration must betaken into account. The apparent resistivity ismeasured in either ohm metres, or ohm centimetres.Cam,.n. cm)

ELECTRODE ARRAYS

There are three main arrangement of electrodes,the Wenner array, the Schlumberger array and theSingle Electrode array. Whilst others are in use,it is beyond this article to go into them.

1) The Wenner Confi~ration is attributed to F.Wenner (1916) who pioneered much of work in thefield of resistivity with this array. In the array(fig 2), all the electrode separations [a], areequal so that the apparent resistivity becomes

p = 27J"aR .The separation is roughly equivalent to thedepth below the array, to which the resistivityrefers. This array is moved along, maintaining thespacing for horizontal profiling, or expandedabout the centre point for depth sounding.

2) The Schlumberger array (fig 3) is designed tomeasure resistivity by measurement of the poten-tial gradient. It uses a pair of potential elec-trodes which are close-spaced between a pair ofwider-spaced current electrodes. The distance isincreased in a symmetrical manner for horizontalprofiling, whilst for depth profiling, it may bedone in a symmetrical manner (fig 3a) or in a non-s~trical manner (fig 3b), for depth sounding.With large current-electrode spacing, it is neces-sary to increase the potential-electrode spacingin order to preserve a measurable potential dif-ference across them.

This configuration was used by Palmer (1954,1959). He plotted the resistance readings againstelectrode separation, to produce a graph on whichhigh-resistance anomalies caused by cavities couldbe identified. The depth was found by using theformula

a

where a is the ratio a:b and aO is the electrodeseparation at which the anomaly occurred. Tratman(1963) used this method to locate Pen Park Hole.

* 49 Highfield Rd.FarnworthBolton BL4 OAHENGLAND

This article is reprintedfrom BCRACave Radio andElectrOiiTCs Groul) vol.1no.2 (Winter 1988) pp5-8.

6

The apparent resistivity of the Schlumbergerarray when used in the symmetrical form, is givenby the formula

p= KV/I

where K =rraZ/Zb,

whilst for the non-symmetrical form,in a much simplified form,

it becomes,

p = KV/I

where K = (aZ - xZ)PTZPT / Zb(aZ + xZ).

~ ,,......

:~, '...............I I I II'I~I I : I II I I I It I I I II

,I I I

I I I I II I I t I

xxx xx

FIG 2Wemer

Arr..,

latnl

. .

. ,

. :, A.,

*

,, IX FIG 3

Scht umbt!l'gll'Array

xlltlfll .T---.-

,J

**

00I0IIt

: ,~I I

l- :, .,,:

..............

B

3) The Single Electrode array ha. been used withso.. success (Bristow 1966). It works on the as-sumption that the equipotential surfaces aroundthe single (current) electrode are nearly hemi-spherical, provided that the second electrode isfar enough away to prevent distortion. The twopotential electrodes are placed in line with thecurrent electrode, at distances a and b. They thenmeasure the potential drop between two of theequipotential surfaces. The apparent resistivityis described as

p = Z1I'ab/a - b.

THE CHOICE?

Both the Wenner and Schlumberger methods can beused to give results under most conditions. Thereare advantages and disadvantages of both. If vert-ical measurement is all that is required, then themaths involved in the Wenner array are simpler.However, the array suffers from the major disad-vantages that a) it must all be moved for eachreading, which involves a great deal of labour,and b) it is unable to resolve variations causedby near surface features and deep layers.

.peleODic. 12v. III no. 4 Apr. 1989

The Schlumberger array can, on the other hand,resolve both the near surface and deep features,however, the maths involved in the calculation ofthe results are far more complex. For horizontalwork, the Wenner array is most preferable due tothe fact that the graph curves produced are moresymmetrical, but the Schlumberger is the moreefficient in terms of time and requires far lesslabour than the Wenner array. It, however, suffersfrom the fact that horizontal profiles must bebacked-up by vertical sounding, which adds to thetime that must be spent in the field.

INTERPRETATION

The two soundingmethodseach give differentresults. Constant-separation traverses (i.e. thearray is moved each time) give a picture of theresistivity at ~ given depth along the traverse,whilst the expanding method gives a profile downfro. the electrode point. If the earth was aseries of nice homogenous layers, then interpret-ing the results would be easy. As it is, thelayers are uneven and vary greatly in composition.The problem of two- and three-layer earths becomesquite complex; the full solution is outside thescope of this article. However, the basic idea canbe seen in fig 4, where two layers are. encount-ered. The usual way of resolving these problems isto refer to standard curve. and .ake a comparison;this way, accurate profiles can be _ade.

~--~--

~ p

FIG"

IvI

LOA

~~Hi J1.

ocave

FIG5

7

.peleODic. 12v. III no. 4 Apr. 1989

In use for cavity location, the two-layer curvedoes not present too may problems, so long as theelectrode spacing is greater than any overburden.Usually, however, the area will equate to lime-stone pavement with no or little overburden, sothe problem disappears.

Examples of the types of curve to be expectedare shown in fig 5. The cavity will, of course,show as an area of infinitely high resistance,whilst mineral veins will usually show high con-ductivity due to their metal content and thus lowresistance. Table 1 gives some typical resistancesof various rock types.

TABLE 1: RESISTIVITY OF COMMON ROCKS

1 - 6.4 x 10750 - 107

0.6 - 1033 - 70

3.5 x 102 - 5 x 103102 - 5 x 107

2 x 103 - 10510 - 80

2 x 103 - 10420

SandstoneLimestonesWet limestoneMarlsDolomiteLavasTuffsAll uvi um/sandConglomeratesWet clays

REFERENCES--...--...----

A New Graphical Resistivity TechniqueBristow Colin, Studies in Speleology (4),pp204-227

1966,

Principles of Applied GeophysicsParasnis DS, chapter 4, pp101-105

Cave Detection by Geoelectrical Methods, Part 1 -

ResistivityDay, Cave Notes, 6(6), 1964, pp41-45

A Method of Measuring Earth ResistanceWenner F, Bull. Bur. Stand. WAshington 12, 1916,pp469-478

Location of Subterranean Cavities by GeoelectricalMethodsPalmer LS, Min. Mag., London 91, 1954, pp137-141

Myers,VI I

JO, in British Caving (BCRA) 1962, chapter

Applied Geophysics for Engineers and GeologistsGriffin & KingPergamon Press, 1965, chapters 2 & 3

LETTERS[contiBJed from p. 3]

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

side, and negative on the exposed (male) side. Thedevice or LOAD connector takes negative on the rubber-covered (female) side, and positive on the naked malepin, which is okay as there is no electricity in the loaddevice (radio, lllq), etc.) when it is discomected toshort out against any metal which the exposed pin mightcontact.

These molded rubber plugs come in sets of two with redand black wires appropri ate for one-each source and loadcomection (altho you can ignore the wire color if youwant; they cannot be connected the wrong way, even in thedarkl). The plugs grip each other firmly, unlike theCinch-Jones type that will fallout with any gentle tug.They are also water and mud resistant, which Cinch-Jonesare not. The only inconvenience is that the wires aremolded in; if you want to extend them you have to do asolder and heat-shrink splice (or twist-'n-tape in anemergency), but this is no big drawbeck. Extension cordsand nulti-outlet "octop.JS" dividers are made simply,without any bulky chassis boxes involved.

I've used this type of connector for years on allradio ~ipment, 12-volt soldering irons, spotlights,chargers, etc. I have fOU"ldRIIny other people who use 12-volt auto accessories also using this connector in theirvehicles, and invariably they've figured out how to getthe polarity right without referring to any published"standard."

Ron Jahnsan WASRON12700 Silver CreekAustin, Texas 78727

This is the missing part of D8V8 Johnson's letter(SPELEONICS 11):

... I hope someday to build a VLF-LF "cal'llLlnicationsreceiver" and am in the process of collecting ideas onhow to implement such an animal. The biggest engineeringdifficulties I see in such a project are as follows:

1- Getting sufficient resolution and stability. I figurethat resolution has to be 1 Hz below 64 kHz, andstability should be comparable (16 ppm). Easy enoughto achieve with a good direct synthesizer but thoseguys are expensive and they eat batteries too. Tenyears from now they'll probably be the only way to go,but for now I prefer phase locked loop. Yes, I'm awareof the horrendous attention to detail involved ingetting this kind of performance out of a PLL, whilealso achieving low phase noise and reasonable locktime.

2- Tuning the RF stages. To span (shall we say) 3 to 300kHz can't be achieved just by switching taps on acoil. The problem of tuning is complicated by the needto provide notches at 100 kHz (LORANC) and perhapsother fr~encies in order to maintain mixer linearitywithout having to crank gain down too nuch. Also, ifthe system is based on direct conversion, the frontend wiII demodJlate the harmonics too.

3- Some people want to listen wideband, some want tolisten narrowband, some want to demodJlate data usingstandard RTTY format, some want MAX10-baud protocol,somewant to extract standard time from WWVB's signal,etc. It ain't like 550-1650 kHz where everybody wantsto listen to voice and music AM and nobody needsanything else. How many different reception modesshould be provided? If you satisfy everybody, themachine has to sell for S10,OOO and takes two peopleto lift it.

Sometimes I figure direct conversion is the best way togo, and sometimes I figure upconversion followed bydirect conversion is the best way. Both approaches havemerit. Upconversion costs more, but it relaxes the designof the RF stages so overall it's probably cheaper, esp.if you really do intend to cover 2 decades of frequency.

D8V8 Johnson713 Texas Ave.Los Banos, CA93635

8

MN1300 D 1.5 15000 22.5 1.00MN1400 C 1.5 7000 10.5 0.47MN1203 4.5 4400 19.8 0.30MN1500 AA 1.5 2250 3.4 0.15MN2400 AAA 1.5 800 1.2 0.05MN9100 N 1.5 650 1.0 0.04MN1604 9.0 500 4.5 0.03 2

Lantern batteries:

PC908 F 6 20000 120 1.33 3PC915 F 6 20000 120PC918 F 6 40000 240 2.67 4PC926 F 12 20000 240

IpellOllicl 12v. III no. 4 Apr. 1989

CAPACITIES OF PRIMARY CELLS

Part 1:

From computer newsgroup rec.ham-radio, 25 June1988:

Subj: Capacity of 6V lantern batteries

John Opalkos, N7KBT writes:

>>>>>

What is the mAH capacity of a... 6-volt lanternbattery, preferably alkaline? I want to putbattery backup on a device that draws 750 mAand I need to know how long the battery willlast.

Leclanch~ cells (carbon-zinc) do not have"simple" ampere-hour ratings; the effective ratingdepends upon the load current, whether the loadcurrent is steady or intermittent, and the actualtime periods involved. In addition, one must alsodefine an "end voltage" - which is MUCH more var-iable with Leclanch~cells than with any other typeof cell.

However, to give some ballpark figures:

(1) An Eveready(tm) 610S (2.5 x 2.5 inch lanternbattery) with a 500 mA continuous load willprovide roughly 2 ampere-hours of energy to anend voltage of 4.0 volts. The recommendedmaximum discharge current for this battery is250 mA.

(2) An Eveready 731, which is a 3 x 5.5 inch [7.5x 12.6 cm] lantern battery, wi th a 500 mA con-tinuous load will provide roughly 5 ampere-hours of energy to an end voltage of 4.0volts. The recommended maximum discharge cur-rent for this battery is 500 mA.

> Or, should I just get a deep-discharge lead-acid> battery and a trickle charger?

In this day and age, Leclanch~ cells are reallyoutdated for standby power use. I would suggestthat you use a gel-cell and trickle charger. Youshould be able to buy a 6-volt 4-ampere hour gel-cell for not much more than S 10.00 at retailprices. If you shop around in surplus stores, youshould be able to do much better.

Alkaline F-cells (the size used in lanternbatteries), if you can find them, should contain18-20 ampere hours. Alkaline D-cells contain 9-10ampere hours, depending on manufacturer and age.Four of them and are a smaller and more cost-effective alternative to carbon-zinc lantern bat-teries.

<><>

Larry Lippman @ Recognition Research Corp.,Clarence, New York.

ANSI battery-size designations (as of 1972) are:0, N, AAA, R, AA, A, B, C, D, E, F, G, No.6, inorder of increasing volume. 0, R, A, Band E areused only as parts of batteries, and are no longersold as individual cells.

<> Norm (strong@tc.fluke.com) 9 Feb. 1989

Part 2:

In answer to our request for battery-capacityinformation [SPELEONICS 9, p.11], lickWilliaas ofthe BCRA CaveRadioand ElectronicsGroup sentpages from the catalog of STC Electronic Services(a British electronic-components supplier), list-ing capacities of Duracell(tm) alkaline cells andbatteries. This information seems difficult toobtain in the U.S.

As discussed in the first half of this article,primary-cell capacity depends upon many variables.Testing methods recommended by the U.S. NationalBureau of Standards are described in EvereadyBattery Applications Enqineerinq ~ published byUnion Carbide Corporation.

Several sources rate alkaline D-cell capacityat 9-10 Amp-hrs. Manufacturers have recentlyclaimed process improvements giving 30% more life.Test parameters for the data in the table beloware not known. The relative capacities which wehave calculated should be valid within any chem-ical system and manufacturer.

Capacity 8A-hrDuracell rel. to Seepart no- Size Volts 8A-hr Wehr D-cell note

+ + + + + +------

Notes:

1. MN1203 is the 3-cell battery used in Petzl(tm)headlamps from France. The cells are largerthan AA, smaller than C; they are not commonlyavailable in the U.S. An adapter for the Petzllamp holds three AA-cells which, as shownabove, have only about half as much capacity.

2. MN1604 is a 9-volt "transistor" battery withsnap connectors. Unlike similar batteries whichare stacks of flat rectangular cells, MN1604contains six cylindrical cells smaller than AAAsize, connected by spot-welded stainless'steelstraps. The indvidually-insulated cells can beseparated for special applications.

3. PC908 has spring terminals,terminals.

PC915 has screw

4. PC918 and PC926 are double-width lantern bat-teries. PC918 has eight F-cells in seriesedparallel pairs, PC926 is 8 cells in series.

9

.peleonic. 12v. III no. 4 Apr. 1989

SUMMARY OF THE CAVE-RESCUE TELEPHONE PROJECT(Condensed from Project Summary #1 of the Wasatch Grotto of the NSS)

John Halleck *

The original 10-page booklet is copyright (c) 1989by John Halleck, who has given Speleonicspermis-sion to publish this condensed version. Thisversion may be reprinted for non-commerical use byrescue groups.

Our original cave-rescue telephones (called MurphyPhones) were standard telephone handsets withtheir earphones and microphones wired in series,both sets in series with a battery on the surface.These cost about $7.50 each to produce; most ofthe cost is in making them "caveproof."

.

.MarkI

This simple but reliable arrangement solved theimmediate problem with simplicity, durability andlow cost, but was not compatible with the standardmilitary-surplus field phones that others mightbring to a rescue.

The main advantage is more subtle: When talkinginto a phone, you can hear your own voice in theearpiece. Telephone people call this "sidetone."The easiest way to test for it by blowing into themouthpiece. If you can hear yourself blowing, you"have sidetone." Sidetone was to become the mostimportant element of the phone testing and design.

The original series-circuit design failed wheneverthe line was broken. When phones went dead, every-one knew there was a problem, and immediatelysought to repair it. Even local children recruitedto test phones were able to debug this simplecircuit.

Disadvantageswere that the surface phone, havinga battery, was different than the undergroundphones. Confused practices with "Everybody grab aphone and go set up" tended to result in either nosurface phone in the net, or several. Such prob-lems were always quickly cleared in such a simplesystem.

While the Murphy phones are a design that anyrescue group can produce cheaply, the incompati-bility with standard field telephones remains asignificant problem for any group that partici-pates in rescues with other groups.

Our first field-phone-compatible versiondesign suggested by Frank Reid:

was

IlL FII1III

( .

MarkITA

The capacitor keeps any DC on the line from sat-urating the transformer, and presents a highimpedance to the high-voltage 18Hz ringing signalthat field phones generate. The transformer actsas an "autotransformer" to impedance-match theline and the earphone. This version receives quitewell but does not transmit to the line as well aslater models.

The Mark II-A version solved compatibilityproblems but had undesirable sidetone properties:When the line connection begins to fail, morecurrent is shunted through the earpiece and isunavailable for the line. The worse the connec.tion, the louder the sidetone-- The user soundslouder to himself, and talks softer to compensate.

Such behavior made line trouble less noticeable,thus delaying repairs. Field tests proved that weneeded a field-phone-compatible unit having thesidetone characteristics of the original Murphyphone, i.e., no connection = no sidetone.

The Mark II B addressed the problem with a secondtransformer. We reasoned that if the direct-con-nection phone worked well, then stepping the sig-nal up and down by the same amount would also workwell. .

MarkITB

The Mark II B transmittedly. It restored desirablesounded faint because oftransformers.

well but received poor-sidetone behavior, butsignal losses in the

a

* P.O. Box 8489Salt Lake City, Utah 84018-0488

10

We triedearphone:

putt i ng all the line intopower .

.Markn c

This Mark II C version transmits badly and re-ceives worse due to impedance mismatch. We decidedto learn more theory and try again.

FINALLY...

We have settled upon the Mark II D design. Ittransmits and receives well and is as easy todebug as the original Murphy phones. It is compat-ible with standard field telephones, and can beattached in parallel with a network of Mark Iphones. Each phone costs less than S15 to produce.For total compatibility with Mark I phones, attacha 1K resistor across the binding posts of the MarkII D's. .

Markn D

All Mark II designs have an important differencefrom the Mark I telephones: They can work througha single-wire line and "ground loop." (More onthis later.)

Mark II D phones' only problem is that they haveno bells or ring-generators. This has proved aminor problem within our group, but caused somecomplaints at the NCRC annual cave-rescue trainingseminar. Of several solutions to the ringer prob-lem, none yet produced are compatible with stand-ard field telephones while being simple, ruggedand cheap.

USING PHONES IN "ONE WIRE" MODE

We have tested "One Wire" mode extensively withour current telephone model. This arrangement usesa single wire between telephones, with the otherwire from each phone connected to earth ground.This mode is also called "ground loop" mode. Inall trials thusfar it has worked well, transmit-ting over 600 feet into a cave in one attempt, andover 1500 feet in another on the surface.

.pel.onte. 12v. III no. 4 Apr. 1989

the The most important consideration seems tocontact at the ground point, regardlessstate of the earth between the points. Anmud at both ends makes a big difference.

be goodof theinch of

We have found that the best approach is either tostick the wires into mud, or to pour a littlewater on the ground and make a mudhole for thewire. An inch of bare wire in mud is better thanseveral feet of wire in dry dirt. Salty waterworks better, but seldom enough better to beworthwhile.

We have found no place where "ground loop" did notwork, but we are not yet confident enough toestablish this as our default method.

NETWORKS OF PHONES

Mark-I phones worked well with more than twophones in series (as expected) and in parallel(unexpected). We needed another 1.5 volt cell inseries to drive two underground phones in series.

The final model works well when added in parallelto networks of the original Murphy phones, or tonetworks of standard field telephones. We have hadas many as seven phones in a network, including amixture of original (in 2-wire mode) and Mark IIversions (in both one and two-wire modes).

QUICK IMPROVISED CAVE-RESCUE TELEPHONES

What is the cheapest method for having cave com-munications available when needed This model isequivalent to the original Mark I design andshares both its incompatibility with standardfield phones and its inability to run in one-wiremode.

Prepare two cords in advance, and beg, borrow orotherwise obtain two handsets at the time of therescue.

Start with two telephone handsets with cordsattached. Cut off the "modular" connectors on theouter ends of the cords.

Inside the handset cord are four insulated wires:

The inner pair of wires go to the earphone,two outside wires connect to the microphone.

the

Each of these "wires" has something resemblingtinfoil inside. This "tinsel wire" is, at best,hard to work with, and very hard to solder.

The easiest way to terminate the wire iscrimp connectors (available at Radio Shackautomotive-parts stores).

withand

Bend the wire over, slip a crimp connector overit, crimp it on. The resulting connection isreliable and durable.

Strip 10 cm (3 or 4 inches) of outer sheaththe cord end. Put a terminal on each wire.

from

Jl

.p.l.ODic. 12Y. III no. 4 Apr. 1989

A

B

For both surface and underground phones, connect-ors "C" and "D" go to the telephone lines.

For the underground phones,together.

connect "A" and

For the surface phone, connect "A" to one side ofthe battery, and "B" to the other side.

You now have cheap, workable phones which will runfor weeks on a single 1.5 volt cell. If using morethan one underground phone, you may need to add anadditional 1.5 volt cell for each undergroundphone. The easiest way to make the connections iswith wood screws in a block of wood, holding theconnections under them.

Since these connections do not affect the handsetitself, you need only the modified handset cordsin the rescue cache.

Parts used in the phones

"''''''''''''''

..............

Microphone: This is the standard carbon microphonefound in the mouthpiece of Bell System (~esternElectric) telephones.

Receiver: This is the standard 1000-ohm telephoneearphone. It comes with a metal oxide varistorbetween the two terminals; leave that in place.

Binding posts: I use two Radio Shack 274-661 (sup-plied in a package of four). Smaller types areavailable; the large terminals are worthwhile forextra durability.

Transformers: Radio Shack 273-1380. Primary: 1000ohms center-tapped; secondary 8 ohms.

Capacitor: 1 microfarad nonelectrolytic; 100 voltsor more, e.g., Radio Shack 272-1055.

Battery holder: Radio Shack 270-398 (holds twoAAA-cells). It has been argued that using AA cellsinstead would make it easier to find batteries.Radio Shack's AA holders (270-382) have provenunworkable; they break when exposed to extremeheat or cold with batteries installed. They dohold up if the batteries are stored separately.

Internal wires: I use 20-gauge (0.812 mminsulated stranded wire.

dia.)

Electrical tape: Needed on all connections; therehave been problems with nuts coming loose on theinside, causing intermittent shorts.

BUILDING RUGGED PHONES

1. Use the older ~estern Electric (AT&T)(Model 500). The new electronic typesless durable. Test used handsets andtheir insides before buying;

2. Dismantle the handsets. You should see screw-onmouthpiece and earpiece caps, a receiver (withgreen and white [or yellow] wires), a carbonmicrophone, and a plastic base for the mike(with red and black wires), and a modular jackattached to the base.

handsetsare much

inspect

"B"

3. Remove the modular jack, grab each of the con-tact wires and bend them out straight in frontof the jack. You should now be able to removethe wires from the jack. This will leave allwires accessible from the mouthpiece; they willall have copper wire pins on the ends.

4. Break-offin placethe linephone. )

the tabs that held the modular jack(You will need the space to install

binding posts at the bottom of the

5. Drill holes for the binding posts, and installthem. It is best to drill the holes slightlytoo small, since screwing-in the binding postsseals them watertight. Don't place them so thatthey prevent reinserting the receiver and mic-rophone.

7. Seal the hole at the end of the phone (thatformerly held the connector) with siliconerubber. DO NOT get the rubber on unprotectedmetal. (It is corrosive during the curing pro-cess.) Ordinary candle wax brushed on the metalwill protect it from the rubber if desired.Cover the hole from both inside and outside sothat the seal can't pop out in either direc-tion. Let the glue cure overnight (Leaving thehandset disassembled aids curing.)

8. ~hen putting the earphone back in, coverwith a plastic bag and carefully screwearpiece cap over the plastic. Cut offexcess.

itthethe

9. Replace the microphone base andcover with plastic between thethreads as above.

microphone,cap's screw

PRECAUTIONS

1. Do not overtighten the binding posts when at-taching the phone line. Finger tight only!(Overtightening may twist the binding posts onthe body and short things inside.)

2. After attaching the wires, wrap them around thephone a few times, and tape or tie a strain-relief loop to protect the binding posts andtheir connections in case the wire is jerked.

12

v. IIIspeleonics 12

no. 4 Apr. :331

PHOTOS OF LUMINESCENTCAVE MINERALS WANTED

[Received 31 January 1989]

Union International de Speleologie

To All the Members of the Commission

Bologna May 10, 1988

Object: Request of co-operation for an Internat-ional program on the luminescence of cave minerals

Dear Colleagues,

According with the resolution taken during ourinformal reunions held in Bulgaria and USSR lastyear, I am writing you to ask for help in order toimprove our knowledge in a field (that of lumines-cence of cave minerals) till now neglected or, atleast, not sufficiently developed.

The aim of this program is to print an "Inter-national Atlas on cave luminescence" in the nearfuture.

Our colleague Y. Shopov from Sofia will be theleader of this program and will perform all thelaboratory analyses.

What is asked you is simply to take slidesfollowing the enclosed instructions and to sendthem directly to Shopov.

In the "Atlas" all the material will be clearlyreferred to their authors.

I hope that all of you will make the maximumpossible effort to help our Commission to reachthis goal.

Please send this information to your colleaguesor friends, who may be interested in such kind ofactivity.

Thank you in advance,

The President of the CommissionProf. Paolo Forti

U.I.S. COMMISSION ON PHYSICAL-CHEMISTRY AND HYDRO-GEOLOGY OF KARST INTERNATIONAL PROGRAM FOR THESTUDY OF THE LUMINESCENCE SPECTRA OF CAVE MINERALS

The aim of the program is the determination ofthe colours, the spectra and the elements causingspeleothem luminescence; at the end of the re-search an atlas on the luminescence of cave miner-als of the world will be printed.

The program is divided into 3 stages;

I - The collecting of luminescence slidesII - Their spectrophotometry by Shopov's method

III - The edition of the atlas on the luminescenceof cave minerals

All cavers interested in this program are wel-come to participate in the first stage, followingthe given instruction to obtain phosphorescenceslides.

The second stage will be performed in Shopov'slaboratory at the university of Sofia.

Speleothems growing in caves close to ore bod-ies, or in hydrothermal environments, as well asin lava tubes, normally are the more interestingones from the luminescence point of view.

INSTRUCTIONSFOR TAKING SLIDES OF LUMINESCENT CAVEMINERALS

1) A reflex camera with"M" or "FP" synchronizer

for magnesium flash and curtain shutter is nec-essary to obtain phosphorescence slides. Somecameras like EXACTA, ZENIT-B and other old camerashave a built-in "M" synchronizer with a 0.0030.01 second delay. Modern cameras need an addi-tional shutter delayer.

2) Electronic flash(es) with leading number higherthan 25 are necessary for the excitation of phos-phorescence. The power of flashes must be as highas possible. Several synchronized flashes may beused to increase illumination.

3) Only colour-slide daylight films with a speedas high as possible (400-1000ASA) are to be used.

HOW TO TAKE THE SLIDES

1. Put the camera on a tripod.2. Take a normal slide of the sample: Macrophoto

is better.3. Put shutter rate in "B".4. Connect flash(es) with synchronization jack

"M" ("FP").5. Put the flash(ES) as close as possible to the

speleothem, but take care that it will befully lighted.

6. Open the diaphragm completely.7. Switch all lights off.8. Make a test shot with closed eyes; open them

immediately after the shot. Correct theposition of flashes if necessary to obtainhigher phosphorescence.

9. Keep the camera open until full extinction ofthe emitted light is reached.

10. Leave 3-4 cm of unexposed film (to obtain a"black" sample).

11. For each speleothem prepare a "normal" slideand a well-exposed phosphorescence slide (ov-erexposed slides are not useful for spectralprocessing).

12. Make a list of the slides (see the accompany-ing form) and mail them together with the"black" sample to:

Y. Y. Shopov, Bulgaria 1408, Sofia, DimitarManov 74

FORM TO BE FULFILLED FOR EACH SLIDE

1. Photographer: (name and address)2. Type of camera3. Used films and speeds4. Location of sample; country, cave5. Rock in which the cave is developed6. Kind of cave mineralization: a) normal speleo-

them; b) guanogenic; c) volcanic; d) hydro-thermal; e) metamorphic

7. Temperature in the cave8. Mineral composition of each sample (if known)9. Type of speleothem for each sample

10. Possible additional data

13

.p.l.ODlc. 12v. III no. 4 Apr. 1989

RESOURCES: ULTRAVIOLET LAMPS FOR MINERALOGY

We plan a future article on portable ultravioletlamps for cavers. The following is digested from adiscussion on computer newsgroup sci.electronics:

Where can I get "black light" (longwave ultra-violet) fluorescent-lamp tubes? When disco musicwas big in the '70s, they were available in everygrocery store but now even the Edmund Scientific"Industrial" catalog doesn't have them except insuper-expensive assemblies. I'm looking for a 4-watt UV tube to replace the white tube in a RadioSh** battery-powered fluorescent lamp, to be usedto illuminate fluorescent cave formations.

(Actively growing white-calcite speleothems areusually fluorescent. They are blue under longwaveUV, green when excited by a xenon strobe. Theeffect is believed to be caused by includedorganic-decay products.)

Frank Reid reid@gold.bacs.indiana.edu

What you want is an F4T5/BL or F4T5BLB fluores-cent lamp, made by General Electric and others.This is a 4-watt lamp, approximately6 inches longand 5/8 inch in diameter. It is a bi-pin lampdesigned for a pre-heat circuit (not needed withhigh voltage and/or high frequency excitation).Try any wholesale electrical distributor, such asGraybar Electric. I would guess th~ "lamp to be$5.00 or less.

Larry Lipp88n Clarence, New York

BLB lamps have a longwave (350 nanometer) peakwith a blue filter to eliminate visible light. BLlamps lack the filter and so emit visible light

masking the flourescing effects, but are stilluseful for photochemical stuff (blueprints, etc).There is also a sunlamp phosphor that peaks at 300nanometers, and germicidal bulbs with the rawmercury arc at 250 nanometers. I get this sort ofstuff at Pacific Lamp in Seattle...

Mark Zenier uunet!nwnexus!pilchucklssc!markz

Ward's Natural Science Establishment5100 W. Henrietta RoadRochester, NY ph: (716) 359-2502

They have supplied Science stuff for about a cen-tury. They target the professional/collegiatemarket as opposed to Edmund who targets the ama-teur/scholastic market.

Al Jones acj@cci632

...For the short-wavelengthUV tubes for EPROMerasure, check with any...electrical or lightingsupply house and ask for a "germicidal lamp" asused by barbers. They come in several sizes to fitstandard fluorscent sockets. I bought the 12-wattbulb (about 1'long) for about $15... This lampwill clear 27256's in about a minute...

John De Ar80nd, WD40QC

I've collected fluorescent minerals (don'tworry- not cave formations!) for years, and own a

twin-tube UV light made by Raytech (4W longwaveand 4W shortwave). I think you will get much moresatisfaction by investing in an inexpensive long/short wavelength light professionally made. Themineral fluorescence you want to see will be MUCH

more pronounced with a filter to remove most ofthe blue/violet wavelengths. The blue coating onhardware-store "poster lights" is extremely inef-ficient at removing the unwanted visible light.Also, MANY more minerals fluoresce under shortwavethan longwave. You can get a nice battery-poweredlamp with a single bulb that produces BOTH longand short wavelengths for under (guessing) $30.

Two reputable places that make/sell ultravioletlights for mineralogical use are:

UVP, Inc. (Ultra Violet Products)5100 Walnut Grove AveP.O. Box 1501San Gabriel, CA 91778 ph: 818-285-3123

They have a free brochure about their Mineralightultraviolet lamps. They sell many portable models.

Ray tech Industries, Inc

Industrial WayStafford Springs, CT 06076 ph: 203-684-4273

I'm pretty sure they also have a freeabout their product... This company sellsbuilt units, including LARGE display-casewell as portables.

I'm sure both places sell "replacement"if you want to go that route... Both sellwave, shortwave or long/shortwave (multi orbulb) lamps.

A tip for added enjoyment: Let your eyes adjustto the darkness before using the lamp, e.g., sitin the dark for 5 minutes or so, then turn on thelamp. Your eyes will be MUCHmore sensitive todimly fluorescent and phosphorescent stuff; you'llbe amazed.

brocuresolidly-

sizes as

lampslong-

single

Rick Inzero Rochester, NY

Hardware stores or wherever you buymust sell replacement bulbs for them.

Bug Zappers

John Sparks

[Cartoon from The Carbide DumD (newsletter ot tneBlue Ridge Grotto, Roanoke, Virginia) v.24 no.1.]

14

speleODics 12

v. III no. 4 Apr. 1989

)

JAPANESE CAVE-RADIOUSED IN YORLD YAR II

The device pictured was captured on Guam Island,circa 1944, where it had been used by Japanesetroops for communicating between caves and tunnelsand for directing artillery. It is a VLF C~ trans-ceiver-- The transmitter is a high-frequency buz-zer; the receiver uses a coherer detector. Theantenna was a very long wire (which may have ex-tended outside the caves).

These historic radios were probably well-suitedto their application; they were able to transmitthrough the earth, using frequencies unlikely tobe intercepted or jammed by the enemy.

Cliff Buttschardt (~6HDO) contributed the phot-ograph.

Other Japanese radios of the war are describedin "Imperial Japanese Naval Communications (1941-1945)" by Alice Brannigan, Popular Communicationsmagazine, December 1988, p.20.

In Review:

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BAT DETECTmt

Rakes, Charles. "The Ultrasonic Receiver," ~ Elec-tronics, Feb. 1989 (vol.6 no.2) p.46.

In SPELEONICS11 we wondered about the insides of theBritish-made "Mini Bat-Detector" advertised in Bat Con-servation International's 'bat boutique' catalog.

We have received no news about that expensive device,however, this article contains construction plans for anultrasonic translator which can be built for approx-imately $25 worth of parts, all available from RadioShack. (It's also offered in kit fonn for $34.95.)

The microphone is a piezoelectric tweeter, the bal-anced mixer is a 4066 integrated circuit (which containsfour analog switches). The circuit contains two otherICs and three transistors. The author's model is housedin 4" (10cm) PVCpipe.

FIELD TELEPIDIES

Allen, Sam. "Build II DTMFField Telephone," ~Electronics, Feb. 1989 (vol.6 no.2) p.41.

This article is about converting ordinary home tele-phones into comnon-battery field phones, with selectiveringers made from SS1202integrated DTMF ("TouchTone")decoder chips driving piezoelectric buzzers. The bat-tery, in series with a large inductor, is connected inparallel with all phones.

This deluxe system is perhaps more useful for largeexpeditions than for cave rescue. The DTMF decoderscould be used to remotely control radio phone-patches orother equipment. A comnon-battery system's major disad-

vantage is that a break in the line disables all phonesdownstream of the break. If each phone has its own

"local" battery, then phones which remain connected toeach other on either side of a break in the line con-tinue to work. See article on emergency telephones inthis issue of SPELEONICS.

BCRA CREGv.1 00.2 (~inter 1988)

The British Cave Research Association's Cave Radio andElectronics Group's second newsletter features a reviewof SMAPScave-mapping software, earth-resistivity tech-niques for detecting underground voids (by Phil Ingham;reprinted in this issue), a list of data for Siemens

ferrite toroid cores, a comparison of three ultrasonicdistance-meters, and many interesting letters and shortarticles.

by Jay Jorden, from Habla 12 Abuela del OZTon (Dallas-

Ft. Worth Grotto Newsletter), March 1989 (vol.? no.3).

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