Ask the Wire Chief (2024)

If you have a question about some aspect of Morsetelegraphy, send an email to [emailprotected].Your question will be reviewed by a panel of experts andyou'll receive a reply by email. Selected questions andanswers may appear in Dots&Dashes,a publication of the MorseTelegraph Club.

Please include your full name and location (city ortown, and state or province) when submitting your question.

Contents

Gravity batteries

Question: Are sources available forreproductiongravity batteries? I'd like to have a vintage-lookinggravity battery to display in my office. Finding anythingfor gravity batteries seems to be almost impossible. Thetype I'm thinking of have a wooden top with brass bindingposts. If nothing is available, I guess I'll have tofabricate one from scratch.

�Joe Fehrenbacher, Wichita, KS

Jim Wades: I have seen original gravitycells nowand then, but they are quite rare, having undoubtedly failedto survive the years in many cases. Some MTC members havemade some nice replicas of early batteries, including thoseinvolved in civil war re-enacting (SCARD, etc.)

Check these photos from the FX Chapter Web Page:

• http://www.floridamorse.com/photo_album.0.html
• http://www.floridamorse.com/photo_album.0.2.html

Gravity battery

Chris Hausler: I've had no luck locatingtheseeither. There appears to be a fair amount of interest so I'msurprised no one has started manufacturing them. Basicallyyou need to make the zinc crowfoot and the copper fanfor the two electrodes. The rest is just a glass jar. OnesI've seen (I've seen a few in museums) don't have a top. Oneof the reasons you don't see them is that the zinc electrodewas sacrificial and in most I've seen the "toes"of the zinc crowfoot are mostly gone.

Of course, as I recall reading, if new ones were to bemade, you'd have to amalgamate the zinc with mercury andmercury is considered toxic these days.

Ed Trump: Gravity cells are not hard tomake. Ibuilt a couple small ones several years ago and they powereda four ohm local sounder just fine.

I used large gauge (No. 6 BWG soft drawn) bare copperwire wound in a spiral at the bottom of the jars with aninsulation sleeve on it to route it up along the side of thejar and make the copper wire pigtail.

I cast my own crowfeet out of some "potmetal" I found which turned out to be mostly zinc andcould be melted in a common electric lead pot like is usedto melt lead to make bullets with.

I chiseled out a crowfoot in a piece of wood for a mold,then melted and cast the stuff into a crowfoot-shapedelectrode. I then made a hook out of steel to bolt on it andhang the thing down into the mouth of the jar with. I put awing-nut binding post on the top of it and that was it.

I got some large wide-mouth glass jars that were aboutsix inches in diameter by maybe eight inches deep. My cellswere smaller than real ones. Real ones were in jars abouteight inches in diameter and a foot deep and the electrodeswere bigger. But mine worked just fine for a local four ohmMorse sounder�made it click with authority.

Nothing much is critical. The copper electrode can bemade of large diameter copper wire, sheet copper, or eventhree short pieces of 1� inch copper water pipe or copperpipe couplings (available in almost any plumbing supplyoutlet) riveted together with copper rivets and an insulatedwire on it to come up out of the jar.

The zinc crowfoot is not critical either. Just make amold to cast one that will fit into the jar you wish to use,and make it with four, five or six "fingers" onit. You can hang it from a wooden lid that fits on the topof the jar with an iron bolt or rod to the center of it andnot have to hook it over the side of the jar if you want. Ofcourse if you have a foundry lined up to cast the things,you can have them make a sand mold that duplicates thoseseen in the old drawings.

The biggest problem I had was getting the coppersulphate. You can buy the stuff, but it comes in 50 poundbags and that was just more than I wanted to mess with atthe time. You might be able to get suitable stuff from agardening store as they use it for something having to dowith growing plants. I got a couple pounds of it somewhereand when it was used up I "retired" theexperiment.

Anyway, you put the copper electrode in the bottom of thejar, and cover it with a layer of copper sulphate crystals(the bluestone) a half inch or a little more deep,fill the jar with water and hang the zinc in it so it is aninch or so below the surface of the water.

Then you short-circuit the thing (connect the copperelectrode directly to the zinc) and wait for a couple daysuntil the thing starts to "work" and then you willsee the solution separate into a deep blue copper sulfatesolution in the bottom part of the liquid and the top partstays clear (zinc sulfate). The liquid solutions willeventually divide so that it is half deep blue and halfclear. At this point the cell is at its maximum strength andis ready to be put to work.

The difference in specific gravity of the two solutionsis what makes it separate and the cells must remainabsolutely still so the solutions don't mix. This differencein specific gravity also gives them their name gravitycell. The shape of the zinc electrode gave them the namecrowfoot cell. The blue color of the copper sulphatecrystals used to "feed" them with gave them thename bluestone cell.

I've heard that in the old days they put some mineral oilin to float on the water to prevent evaporation and to keepthe zinc sulfate from growing crystals on the zinc electrodeabove the surface of the solution.

These things are messy and require frequent addition ofcopper sulphate crystals. The copper electrode grows copperdeposits and the zinc electrode is slowly eaten away. Thecells develop about one volt each, and they need to be usedin a circuit that pulls some current all the time in orderto keep them working. It was this fact that made this kindof cell ideal for closed-circuit telegraph work.

The copper sulfate solution level reduces as the copperin it is deposited on the copper electrode and the clearzinc solution increases. When the dividing line between thesolutions reaches under a couple inches from the copperelectrode, it is time to draw off some of the zinc solution(keep it in a dark jug for starting other cells), add coppersulphate crystals to the bottom of the jar, and refill thecell with fresh water to renew it. Short-circuit it for awhile to get it going again and then cut it back into thebattery string.

This job was why old-time agents and operators hated thegravity cell "locals" in railroad depots so muchbefore there were electric lights�and invariably coerced astudent operator to do this messy job if they had one therelearning the telegraph business.

Can you imagine the job of keeping a rack of 100 of thesethings going for a telegraph wire main terminal battery? Thecells could be jumpered out one at a time to remove themfrom the string for maintenance. There wasn't the highcurrent short-circuit danger with these as there was withcommon lead-acid storage batteries. The gravity cells had apretty high internal resistance so shorting them out even atmaximum strength was not an "electrifying" event.

Les Kerr: Additional information on thistopic canbe found in The Gravity Battery section ofG.M.Dodge's 1921 book TheTelegraph Instructor.

Published in Dots &DashesVol. 35, No. 2 (Spring 2009)

Sounder electricalpower

Question: Using a D cell to power mysounder viathe circuit described on the MorseKOBwebsite results in a current of about 200mA when thesounder is energized. This is considerably more than the60mA which I've heard is the normal resting current.Placing a low value resistor in series with the D cellreduces the current, but even with the tensioning springbacked way off it won't sound properly. My conclusion is toobtain the 60mA resting current a sounder with largercoil resistance is needed. Comments?

�Mike Hardie, North Vancouver, BC

Ed Trump: 200mA in the sounderloop withonly a single 1.5volt D cell for loop power is aboutnominal for a 4ohm local sounder. Measure the coilresistance of the sounder magnet windings and, if thesounder is a nominal 4ohm type, make sure it isproperly adjusted.

First, adjust the magnetic gap between the armature thatis mounted on the sounding bar and the ends of the magnetcore pieces. Hold the sounder bar down and set the downstopso that there is about two or three thicknesses of ordinarytyping paper between the armature and the magnet corepieces. The armature on the sounder bar should nothit the coil magnet cores at all. Make sure there is nomechanical defect in the sounder magnet coil mountings andthat they are tightly fastened to the "heel piece"that straps the two cores across the bottom where they mountto the sounder plate so they can't move.

Next check the sounding bar return spring tension. Itshould be just enough to smartly return the sounder bar toits upstop. Make sure the travel of the sounder bar betweenthe upstop and the downstop is about 1/16of an inch or a little less. Also make sure the trunnionscrews where the sounder bar swings from are properly set sothere is no slop, yet the sounder bar moves freely in thesetrunnions without binding. It must be free to be moved bythe magnetic pull on the armature.

If all this is well, the sounder should operate and soundwell as the loop is keyed. Make sure you haven't wired adiode across the sounder coil windings; this will make thesounder sluggish. The sounder driver circuit shows theprotection diode should be connected across the keyertransistor in a reverse direction between the collector andthe emitter.

The normal working current for a 4ohm sounder isabout 250mA. They were designed to operate withbetween 1.5 and 3 volts of battery in circuit, no more.

The only time you should be working with 50 or 60mAin the sounder loop is if you are using a mainlinesounder that has coils wound for 100 to 150 ohms. Inthat case a 1.5volt D cell won't be sufficient voltageat all. For these mainline type instruments you need around20 to 24 volts with additional series resistance in the loopto regulate the loop current to about 50 mA. This would beabout 360 ohms for a 24volt supply and a nominal120ohm sounder. The resistor should be rated for atleast 5watts. The higher voltage is necessary toovercome the high inductance of the instrument windings. Theinstruments will work with less, but they won't always soundright.

Chris Hausler: For mainline instruments of100 to150ohms, I find using a 12volt Radio Shack powerbrick and putting the instrument in series with a150ohm 2watt carbon resistor works well. Thesepower bricks can serve as a simple and readily availablealternative to a higher voltage supply. It's true thatlarger voltages dropped across larger resistors improve thetime constant of the circuit, but I've had no performanceproblems with the above configuration. In a pinch I�veeven used only 9volts and very little seriesresistance successfully.

Les Kerr: In the case of a 4ohmsounder,remember there's a voltage drop of about 0.7voltsacross the Darlington switching transistor that the powersupply must overcome, in addition to powering the sounder.If you use a 1.5volt D cell, for example, that onlyleaves 0.8volts to drive the sounder. Enough to work,perhaps, but maybe not as "snappy" as you'd like.

For my 4ohm sounder, I use a 12volt powersupply in series with a 50ohm, 10watt resistor,resulting in a current of about 200mA. This works wellfor me.

Published in Dots &DashesVol. 34, No. 4 (Fall 2008)

Closed-circuittelegraphy

Question: One aspect of the originaltelegraphsystem has puzzled me for some time. It appears as thoughbatteries supplied power to the system when no message wasbeing passed, i.e. all the circuit closers on the wire werein the closed position and the various stations werewaiting. This seems like a huge waste of batteries. Am Imissing something, or was supplying continuous power to thesystem (and the resulting battery replacement) arequirement?

�Mike Hardie, North Vancouver, BC

Jim Wades: The practice of utilizing anormallyclosed (NC) system offered a variety of advantages, botheconomic and technical, a sample of which includes:

1. In terms of complexity and wiring requirements, an NC loopis less expensive to construct and easier to maintain.
2. NC loops simplify the process of multiplexing, repeating,and similar activities.
3. The process of compositing telegraph and telephone circuitsis also easier and more economical.
4. Faults in an NC loop are readily detected and easier totroubleshoot, particularly from a remote location utilizing a bridge orsimilar device.

As for batteries, the old crowfoot batteries were ideallysuited to an NC loop. By the latter part of the 19thcentury, however, larger telegraph networks utilized powersupplied by generators and, later, rectifier units toprovide the necessary loop supply current for the variouscircuits.

For simple telegraph circuits, say between two points,normally open (NO) systems were utilized. Such systems couldbe powered by dry-cells and the like, and, of course, powerconsumption was an issue. Perhaps the most common examplesare learner's sets and the neighborhood telegraph line!Short telegraph circuits for railroad block operation mightbe another example.

Ed Trump: There were some very good reasonsthatthe closed circuit system was almost universallyusedon Morse wire circuits in the USA and Canada. Single wire, groundor earth return circuits were normally used, whichhad half the resistance of a metallic loop, since the earthreturn contributed no resistance to the circuit ifitwas more than a few miles in length. The only circuitresistance was due to the line wire resistance and theresistance in the instrument windings or other equipment incircuit.

With a closed circuit system, all the battery could belocated at the ends of the wire circuit, often hundreds ofmiles apart. All the other stations only had to have a key,relay and local sounder or perhaps only a key and a mainlinesounder and a rudimentary switchboard for wire testing andpatching.

Mainline battery could be located all at one end of acircuit, and the far end of the wire simply run to earth,but there were some technical reasons for splitting thebattery source in two and locating half of it at each end ofthe circuit. This had to do with improving operation due toline leakage in wet weather and allowed testing for opensand grounds in the circuit from testing offices at the endor intermediate points of the wire.

A typical mainline telegraph wire operated with mainbattery open-circuit voltages of typically 100 to 160 voltsbut the line current was nominally only about 50milliamperes. Thus the actual power consumption was prettysmall per wire.

In the early days racks and racks of Daniell cells or gravity(also known as crowfoot or bluestonecells(producing about one volt per cell) would comprise a mainline terminal telegraph battery. About 100 cells would beall connected in series for a main battery in a terminaloffice. Before long, telegraph companies went to steamdriven dynamos for DC power and later to AC motor-DCgenerator sets or AC to DC rectifier type power sources fortelegraph purposes.

With an open-circuit system, each station had to supplyand maintain its own operating battery to work the circuit,which was an impractical and uneconomical situation for longoverland circuits with many stations or offices on them.

Open-circuit systems were more commonly used for blockcircuits on short stretches of high-traffic railroads, andfor practice sets and some private circuits where supplyingdry-cell battery at low voltages was not costly. Thecircuits were also often as not metallic loops which coulduse low voltage battery supply and ran at much highercurrent levels than long mainline closed-circuit telegraphwires using low level line currents and higher voltageterminal battery.

Another advantage of a closed-circuit system is that itis always under test. That is, it is a series-connectedcircuit and any interruption at any point is immediatelynoticed by all the offices that are on the circuit, becausethe wire goes open and no communication can be carried outuntil the circuit is closed again.

In the case of a wire break, the offices along the linecould each temporarily connect a ground wire in theirswitchboards on each side of their office to ascertain inwhich direction from that office the break was located andstart out a lineman to make repairs. The wire wouldimmediately be restored to operation in the oppositedirection in this case, and the intermediate ground laterremoved when the break was repaired and the wire "cutthrough".

When a wire was not broken but became grounded, thusinterrupting through service, a wirechief at a testing pointnear one end of the wire in question could call up theoffices along the circuit in succession on the wire inquestion or on another adjacent wire and have them eachbriefly open the faulted wire in their switchboards toascertain between which two stations the ground fault waslocated. Then linemen would be dispatched to clear thefault.

Much of the detail of landline telegraphy practices andhow it worked has been forgotten, but there are some booksavailable that adequately describe a lot of it. George B.Prescott's History, Theory and Practice of the ElectricTelegraph is one such book. It was written around thetime of the American Civil war (1866) and is still a goodreference on how it all worked. The technology changed butlittle after that time until the end of the manual telegraphera, circa 1975. Reprints of this book are currentlyavailable from book sellers.

Linking dialup Morseand theInternet

Question: I'd like to connect the localtelegraphloop at Exporail with the Canadian dialup hub. Unfortunatelywe don't have a telephone line available for this purpose,but we do have high-speed Internet. Is there any way we canuse the Internet to make this connection?

�Fran�ois Gaudette, Saint-Constant, QC

Les Kerr: What you'll need is (1) acomputer atthe Exporail site to connect the telegraph loop to one ofthe MorseKOBwires, (2) a second computer at some other location to linkthat MorseKOB wire to the Canadian hub, and (3) an operatingagreement with the MorseKOB and dialup hub wire chiefs toset up the link between the two systems.

1. MorseKOB loop interface

Connecting a key (straight key or bug) to a computerrunning the KOB program is very simple. All you need is apair of wires from the key to a serial port on the computer.If your computer doesn't have a serial port, you can use aUSB-to-serial adapter instead. Details on how to do this arein the MorseKOBTutorial.

Adding a sounder is not much harder, but you'll need tobuild an interface circuit such as the one described in the MorseKOBTutorial. It only requires a few inexpensive parts.

To tie into an existing telegraph loop, like you have atExporail, is a bit trickier. For this you'll need a MorseKOBloop interface. Assembling this circuit requires moreskill than the simple sounder driver, but once you get itworking it does a fine job.

2. MorseKOB dialup interface

Anyone with a dialup modem and a computer running the KOBprogram can provide dialup access to the MorseKOB network.Here's what you need:

• computer with a serial port (or USB-to-serial adapter)
• Internet connection
• 300baud dialup modem (unmodified)
• telephone line
• MorseKOB modem cable

The MorseKOB modem cable is used to connect the modem tothe computer, but it's not the same as a standard,off-the-shelf 9 pin to 25 pin modem cable. It needs to bewired with the following pin connections:

Since the modem is connected to the computer's serialport you won't be able to use an external key or sounder atthe same time, but you'll still be able to send using thecomputer's keyboard and hear incoming Morse over thespeakers.

3. MorseKOB and dialup hub coordination

With the equipment described above, you can enable asingle dialup Morse user to access the MorseKOB networkwhenever you like. Technically, moreover, nothing preventsyou from using your modem to call one of the dialup hubs,which then connects all the users of that hub to theMorseKOB wire. If this is done in an unplanned manner,however, disruption to the system is possible and otherusers could be impacted.

Therefore, it's important to coordinate in advance withthe wire chiefs of the MorseKOB system (Les Kerr) and thedialup hub (Tom Hamblin in the case of the Canadian hub, JimWades for the U.S. hub). Dates and times of operation, theMorseKOB wire number to be used, and other requirements canbe agreed upon to ensure smooth operation for all concerned.

Internet link between the Exporail site and the dialup hub

The block diagram shows the main components of thesystem, with dashed lines representing connections made overthe Internet. XO is the telegraph office at Exporail, and BAis Barrington Station, located �mile away. Theoffices are equipped with 120ohm mainline sounders andthe loop supply voltage is 120VDC. There are actuallytwo separate circuits between XO and BA, but for simplicityonly one is shown in the diagram.

Museum display

Question: I would like to set up a workingMorsedisplay for the Train Depot Museum in Kingsville, TX. Thetrain depot was built in 1904 and I'd like the display toreflect telegraphy of that age. The original telegraphsystem probably required the use of batteries since the townof Kingsville was established in 1904 as a railroad town andat that time the community was not yet on the power grid.

The train line through Kingsville runs from Robstown toBrownsville, a distance of 142 miles. How many batterieswould be required to transmit messages over 142 miles? Howmany volts? If a message was sent from Robstown toBrownsville would it travel the entire distance or would ithave to be copied by a telegrapher and resent somewhere inbetween the two towns?

The museum has a number of mainline sounders and keys,and also a Western Union 4-C relay. I'm setting up a 4 footboard with a key and mainline sounder, and I'm making littletelegraph poles to hold the wires. I want to incorporate therelay as well, but I'm not totally sure what its functionwas. Can you give me a description of its use?

I plan on using a 9 volt battery to power the set up. Howwould the relay be connected? I'd like to simulate a batteryfrom the 1904 era. Would a crowfoot battery beappropriate?

�Patricia Allison, Kingsville, TX

Ed Trump: Telegraph wires were powered bydirectcurrent (DC) and in the 1904 era were powered by large mainbatteries in the telegraph offices at each end of the wire.One single iron wire was used for the line between theoffices, insulated on the poles with the common type glassinsulators. Earth was used for the return current path. Themain line batteries at each end of the line were made up oflarge numbers of one volt cells wired in series to provide atotal voltage of about 100 volts.

With 100 volts of terminal battery at each end of theline, the DC current in the telegraph main line wire wouldbe about 50 to 60 milliamperes for a line around 150 to 200miles long constructed of galvanized No. 8 iron wire, whichwas pretty much the standard for line construction from the1860s Civil War period to the end of the telegraph era inthe 1970s � over 100 years.

A telegraph line would easily work over the distance fromRobstown to Brownsville. That is, Robstown could easily senddirect to Brownsville without any relaying done at anyintermediate point.

Since a telegraph wire is a series DC circuit, any officeconnected in the line could send and all the other officesin the circuit would be able to receive the message. Thetelegraph keys had a circuit closing lever on the rightside, and when the key was not actually being used to sendwith, this circuit closer had to be kept closed to keep theline circuit closed, else no communication could be done. Anoffice wishing to call another office would open the circuitcloser on his key, then work the key to send the Morse codecall letters of the office it wished to communicate with,and then close his key circuit closer to wait for thedistant office to answer.

Morse relay

The Morse relay was an instrument that wasused innearly all telegraph offices circa 1904. Its purpose was torepeat the Morse signals from the relatively small currentin the main line wire into the local loop circuitthat was connected to the contacts of the relay and operatethe local sounder with a clear and distinct signal no matterhow weak the signals were in the line circuit.

The electromagnet coils in the relay were connected inseries into the main line circuit from the switchboard wherethe main line wire was brought into the office from thetowns in either direction. The contacts on the mainlinerelay were connected so they could make and break thecircuit to the local sounder magnet windings. The localsounder circuit was powered by two crowfoot cellsthat provided about one volt each. The crowfoot cells werewired in series with the local sounder coils and the relaycontacts. Battery type local sounders were wound to aresistance of about 4 ohms and used 3 volts for battery.Local circuit current was about 250 milliamperes with the 4ohm sounders.

Telegraph office with relay and local sounder

Each telegraph office on the same line was equipped witha switchboard, a key, a main line Morse relay, a localsounder, and a local battery. The main line wire came intothe switchboard from each direction, and was then connectedto the instruments on the operator's table. This put therelay magnets and the key in series with the line circuit.The contacts on the relay were connected in series with thelocal sounder and the local battery, which normallyconsisted of two crowfoot cells in series.

The switchboard had a ground wire available on it andmeans of opening the line circuit on each side of theinstruments in the office and attaching the ground wire inplace of the line wire. This was provided so that if theline wire were to be broken down or burned down by lightningin one direction or the other, the operator couldtemporarily connect the ground wire and thus restorecommunications with the distant offices in the oppositedirection from the break in the line, using the currentprovided by the terminal battery at that distant end of theline.

Of course if more than one wire ran along the pole line,the switchboard provided the means of not only connecting inthe relays and keys in the office assigned to the otherwires, but provided a means of testing and crosspatching theline wire circuits if it became necessary in case of linetroubles.

To set up a simulated telegraph circuit, ideallyyouwould need a Morse relay, a key, and a local sounder at eachend of the display on your board. You would then equip eachend of the line with a local circuit connected to the relaycontacts and two cells of (simulated) crowfoot battery forlocal circuit power and the local sounder.

If you have only one relay, you can substitute a mainline sounder at the other end and wire it in series with thekey and not use a relay and local sounder. This was commonpractice in offices where maintenance of a local circuit andits batteries was not desired.

If you don't have any local sounders, you may use amainline sounder in place of a local sounder in the relay'slocal circuit. You will have to use about 6 volts DC for thelocal circuit instead of 3 volts as the 120 ohm main linesounder needs more battery to work.

The main line circuit would then use one single wireconductor between the "offices" on your smallpoles. You would have to hide a wire under the board tosimulate the "earth" return connection.

For a simple display like this, you don't need to providemain line battery at each end. Putting it all at one endwill suffice.

To power the main line circuit you will need about12volts DC to power it properly. Each relay or mainline instrument in the main line circuit will be about120ohms, two instruments in series will make the totalcircuit resistance about 240ohms. Ohm's law says thatthe current times the resistance will equal the voltageneeded in the circuit. (Voltage E in volts = current I inamperes x resistance R in ohms.) In this case you will wantabout 60 milliamperes or 0.060 amperes to properly operatethe telegraph instruments, and you have about 240ohmsresistance in the circuit neglecting negligible resistancein the connecting wiring. So 0.060 x 240 = 14.4 volts willbe needed for power in the main line circuit. You should beable to find a small "wall wart" DC power supplythat will provide 12-14 volts DC at 100mA or so topower your exhibit with.

For the local circuit on the relay, use six volts DC topower the 120ohm main line sounder if one is used as alocal sounder.

We do ask one thing�VERY IMPORTANT�If you display a copyof the MORSE CODE with your display, PLEASE make sure youdisplay the AMERICAN MORSE Code which was the code used ontelegraph wires in the U.S. and Canada, and not the"International" Morse code as is used on radiocircuits by radio amateurs.

Line inductance

Question: Conventional telephone twistedpairbuilds up capacitance rapidly, necessitating addition ofload coils or other equalizing methods to pass the higheraudio frequencies. In a single wire elevated above ground asin telegraph circuits it would seem line inductance wouldbuild up on very long runs, capacitance not building up asit does on twisted pair so rapidly. What effect does itactually have? It seems inductance would make the soundersound "soft", not a sharp snap.

�D. E. Wiggins, Valparaiso, IN

Ed Trump: Single wire earth-return DCtelegraphcircuits suffer very little from line inductance. The lumpedinductance of the magnet coil windings in the seriesconnected telegraph instruments far outweighs thecontribution of distributed line conductor inductance, andis mostly responsible for line current rise-time delay.

Very long circuits will have distributed capacitivereactance with earth that somewhat counteracts the inductiveproperties in opening and closing the circuit, but thecombined effect is fairly negligible on even long open wiresingle conductor circuits.

As long as the open-circuit terminal voltage applied tothe circuit is sufficient to reduce the line current risetime when the circuit is opened and closed, the distributedinductive and capacitive properties of the line wire itselfhave little effect on circuit operation. This is one reasonmain line terminal battery voltages were kept at a fairlyhigh value, usually higher than 80 volts, and typicallyaround 130 to 160 volts at each end of very long circuits. Polarcircuits, where the operating battery is reversed inpolarity rather than simply turned on and off on thecircuit, are affected by line conductor inductance andcapacitance even less.

DC telegraph operation over cable circuits, where theconductors are in close proximity with other cableconductors and the cable sheath, is much more affected bythe higher distributed capacitance in the cable. Operationis much different than that of open wire line on poles inregard to both keying speeds and distance that can be runwithout regenerative repeaters.

Published in Dots &DashesVol. 35, No. 1 (Winter 2008-09)

Field telegraph set

Question: I have just started to get intosignaling and Morse code and a friend found me two SignalCorps telegraph sets at a garage sale. These are U.S. ArmyTG-5-B sets complete with headphones, buzzer and key. Theywork, but I know absolutely nothing about hooking them up.According to the wiring diagram's instructions I think Ineed a 45 volt power supply.

Where can I get the instruction manual for this type oftelegraph set and do I need a 45 volt supply or is thatamped up from the battery box in the unit?

�Mark Horn, Kelso, WA

Les Kerr: You're in luck! The instructionmanualfor your telegraph set can be downloaded from www.royalsignals.org.uk.This marvelous site has manuals for a wide variety ofmilitary equipment (most famously the No.19 wireless set,which I used as my first ham radio station many years ago).The manual you need is TM11-351, which covers the TG-5and TG-5-A telegraph set, and you also need the July 1943supplement for the TG-5-B model.

TG-5-B Field telegraph set (click to enlarge)

You won't need a 45 volt supply to operate your telegraphset, or even the 22.5 volt line battery that it originallycame with. The TG-5-B has a 4,400 ohm relay that can beadjusted for line currents as low as 0.2 mA, so a 6 voltscrew-top lantern battery (NEDA 915 or equivalent) shouldwork nicely with your pair of sets. Or, instead of a lanternbattery, you could make yourself a battery pack that acceptsfour D cells. You'll need a separate line battery foreach set, and also a pair of D cells per set for the localbattery.

The line battery is connected to the binding posts marked+ and -22. The only other thing you'll need is a pair ofwires between your two sets connecting binding posts L1 andL2. The manual gives detailed instructions on how to testthe installation and adjust the relay spring tension forproper operation.

Published in Dots &DashesVol. 35, No. 1 (Winter 2008-09)

Learning AmericanMorse

Question: I'm a ham radio operator, NY�O,and I'dlike to know if there's some kind of course available forthe landline Morse code. I like the old western TV shows andyou hear the landline Morse on occasion, but I only know theinternationalcode.I'd like to be able to learn a little click and clack Morse.Are there any online courses available?

�Ben Johnson, Mount Union, IA

Les Kerr: The "KOB Morse Course" wasdesigned exactly with someone like you in mind: the CWoperator who wants to make the transition to American Morsewith a sounder. The course works in conjunction with theMorseKOB program, which can be downloaded from morsekob.org.Click on the "KOB Morse Course" link on theMorseKOB home page to download the course material.

The best thing about the KOB program is that you can alsouse it to hear live operators sending landline Morse overthe Internet. In fact, Sid Vaughn, one of the pioneers ofInternet Morse, lives not far from you in Cedar Rapids. Sidhelped shape the KOB program's design to make it more usefulfor CW operators like yourself.

Strangepunctuation codes

Question: I noticed in TheTelegraph Instructorby G.M.Dodge (7th edition, 1921) the table forthe Continental or International Code gives strange codesfor some of the punctuation marks. For example, the codegiven for the period (������)is neither American Morse nor standard InternationalMorse/Continental Code. What�s going on here?

�Ernest Unrau, Morden, MB

A page from the 1921 edition of The TelegraphInstructor,
by G.M.Dodge. Note the unusual codes given for
the period, comma, and exclamation point.

Les Kerr: This was the toughest questionsent tothe Wire Chief so far, and it very nearly stumped our panelof experts. It was tempting to dismiss these weird codes asmistakes by Dodge or typos introduced by the book�spublisher.

Further investigation revealed there�s more to thestory, however. The January, 1939, issue of QST advises hamsto "use new punctuation symbols." The QST articlegoes on to provide the following explanation:

The International Telegraph Regulations, as revised atCairo, 1938, made certain changes in the International Morse Code asfollows:

(a) The former period sign ������was changed to ������

(b) The comma sign shall be ������

Therefore, at the time Dodge wrote his book, the codes hegave were correct.

Digging even deeper, I discovered that the originalContinental/International code for the period, standardizedin the mid-1800s, was a string of six dots (������).The extra spacing wasn�t introduced until around 1900.

It�s interesting to speculate why the original code wassix dots, why it was later broken into three groups of twodots, and how it finally transitioned to the code we havetoday. Perhaps the string of six dots was too easilyconfused with the number 5 (five dots) or the error signal(eight dots). And the underlying rhythm of the modern codefor period, didahdidahdidah, is exactly the same asfor the spaced code didit didit didit.

The most intriguing document I came across during mysearch for information was a 166-page report written in 1869by Samuel Morse himself. Morse was a U.S. commissioner tothe 1867 Paris Universal Exposition, and his report is acommentary on what he observed there.

Chapter 3 of Morse�s report addresses the topic ofcodes, and it provides some fascinating insight into histhinking on the subject. Morse apparently had secondthoughts about the wisdom of the spaced letters in hisoriginal code, and he generally supported the Europeanefforts to update the code. He did not agree with theirchoice of codes for punctuation, however. His ownrecommendation for the period, in fact, was a single dot�thesame as the letter E!

Published in Dots &DashesVol. 35, No. 3 (Summer 2009)

Lubricant fortelegraphinstruments

Question: What lubricant should be used forkeys,relays, sounders, and other telegraph items?

�Garry Tidler, Sharpsville, IN

Chris Hausler: I'd suggest a cleaning ofthe"bearing surfaces". I've seen cases where rust andor grime will interfere with the pivoting of a key orsounder at the trunnions and all that is needed is a goodcleaning and maybe a little polishing and rust removal withemery cloth or some similar fine abrasive if necessary(unless it's real bad and more aggressive procedures areneeded). I just usually use some paper towel and that'sabrasive enough. I suppose a little graphite wouldn't hurtfor lubrication if believed to be necessary, but I wouldn'tuse any oil of any kind.

Jim Wades: I agree with Chris's assessment.I'venever lubricated a telegraph instrument. However, if I wereto lubricate a bearing surface on a telegraph instrument, Iwould probably use Rem Oil, which is readilyavailable at gun stores or any sporting goods store thatcarries firearms. I would also use it sparingly.

Derek Cohn: For pivots, I have to agreewithChris. I think in very few situations have I had to add alubricant. Usually, if a pivot isn't working properly, it'sdirty and/or rusted. I clean off the dirt and/or remove therust and the bearing seems to work fine. I sometimes smear3-in-1 oil onto the cleaned surface but that's to retardfurther rusting. I don't see any harm in adding a little bitof oil to the pivot points, though some people might pointout that it's an insulator and many of the pivots are in theloop path (which is why Vibroplex adds the copper pigtail totheir bugs with jeweled bearings).

For moving threaded parts, such as dot contact screws,spring adjustment screws, etc., I use 3-in-1 mostly becauseof the handy can dispenser. The teletype guys who I palaround with hate 3-in-1 oil for their machines(butthose are high wear, high temperature, high contaminantapplications) and say that Teletype corporation recommended20w non-detergent motor oil. I was able to find some at ourlocal "good" hardware store (not the big-box type)and that's probably what I should use for lubing my keys.

In summary, I think most stuck pivots are the result ofcrud/rust that can be cleaned off to make the travel moresmooth. Add any oil you like afterwards. To improve thetravel of threaded components, I use 3-in-1.

Office wiring

Question: How was a railroad telegraphwired to the line? I've never been able to find drawings or photoswhich show the actual, physical methods of tapping the overhead wireand bringing the wiring into the station building ---- including themeans of providing for lightning protection and physical location ofthe hardware.

�John Schneider, Roswell, GA

Ed Trump: A telegraph circuit is a seriescircuit; that is, all stations are connected in series with oneanother. Any station opens the circuit and sends, all the otherstations connected on that wire receive what is sent.

The telegraph line wire is physically broken on a designatedpole near the station by means of what is called abreak iron. This is a short iron bar about eightinches long, an inch and a quarter wide, and about half an inch thick.On the ends of this bar are two metal insulator pins, with wood cobsand standard telegraph insulators screwed thereon.

The break iron is mounted on the top of the crossarm so thatthe two insulators are in line with the wire to be cut in. The wire iscut anddeadended on the two insulators. The wire is pulled around theinsulator and twisted on itself twice, then threebuttons are wrapped around the main wire, and ashort "pigtail" is left pointing down. This provides abreak point in the telegraph circuit in that wire, and preserves thestrength of the pole line construction.

Early construction then ran two wires from the break iron in aslack span down to some insulators fastened to acrossarm fixture on the station wall to bring both directions of thecircuit to the building. Smaller gauge copper wires then attached tothesedrop wires, and ran inside the building through insulating bushings tothe location of theswitchboard.

Later construction utilized a cable boxlocated on the top of the station's cable pole. Smaller gauge insulatedcopperbridle wires were connected to each pigtail on eachside of the break irons and then routed up into the cable box throughinsulating bushings where they were connected into the cable that randown the pole and into the station building to the switchboard location.

Early switchboards were generally of the crossbartype with the line connections for each circuit entering the buildingconnected at the top of a pair of vertical brass straps mounted on ahardwood backing that was in turn mounted on the wall, or in heavylightning districts, mounted on some iron straps that stood it out awayfrom the wall eight inches or so. This was to prevent lightning fromsetting the building afire in case of direct lightningstrikes�hopefully the resulting fire in the switchboard could beextinguished before it set the wall afire. Sheets of tin were usuallyfastened to the wall behind such switchboard installations to providefurther fire protection.

There was a pair of vertical straps for each wire terminatingin the switchboard, thus presenting both directions ("east" and "west",or "north" and "south") of the line circuit for making connections. Theoffice instruments, telegraph relay andkey, were connected via crosswise copper straps on the back side of thewood switchboard frame that connected with brassbuttons or discs on the front of the board locatedbetween each vertical pair of line straps. Holes were arranged betweenthe vertical bars and the rows of horizontal discs so that little brasspegs with insulated knobs could be pushed in to make connectionsbetween the discs and vertical straps. Any vertical bar could beconnected with any horizontal disc, making it possible to connect a setof instruments, open, ground and crosspatch to any wire in theswitchboard.

Each wire that had instruments assigned to it had a pair ofpegs in the switchboard connecting the key and relay to the east andwest (or north and south) directions of the circuit. The key and relayfor each wire were connected in series with one another at thetelegraph desk or table. In this manner, the telegraph circuit made acomplete loop from the "east" line into the station, to theswitchboard, through the key, relay back through the switchboard andback out to the "west" line.

When the telegraph office was unattended, Company rulesusually dictated that the instruments on all wires in the office wereto becut out or disconnected from the line circuits atthe switchboard. This was easily accomplished by moving one of the pegsin the board.

A typical railroad way office would have three sets ofinstruments, a key and relay, on the telegraph table. One was typicallyfor theRailroad Dispatcher's wire, one was for the Railroad Company messagewire, and a third set was for the Western Union way wire. There werepossibly other "thru" wires brought into the switchboard for testingpurposes only, that did not have instruments assigned to them. Thesewires were simplycut through at the switchboard and not disturbedexcept on specific direction of the distant wire chief in case oftesting for troubles.

Lightning protection in the early installations wasrudimentary and consisted of only a horizontal brass strap that waspositioned across all the vertical line straps on the front of theswitchboard with a small air gap of a couple thirty-seconds of an inchbetween it and the line straps. The horizontal bar was permanentlyconnected to the station's ground plate buried in the earth.

Near lightning strikes on the line would cause arcing betweenthe ground strap and the line straps on the switchboards, and theground strap would have to be taken off occasionally and carefullydressed with a file to remove pitting damage due to this arcing. Thisarrangement normally provided sufficient protection to all but directlightning strikes on the linenearby. Nothing much protected the office from those, and lightningdamage to instruments and switchboards was not uncommon.

Additional holes between the line straps and the ground bar onthe switchboard allowed connection pegs to be inserted toground any wire "east" or "west". In case of a linefailing open this was done to determine in whichdirection the trouble was from the station.

Later improvements in switchboard design after the turn of the20th century provided line and instrument fusesand better lightning arrestor devices, and provided line and patchingjacks for each line and instrument connection so that wire patching andtesting was made easier and safer for the operators.

Edited by LesKerr
Revised 2010-04-18
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