|
Egad…wireless telegraph.
Who would dare think of such a thing? | 
|
It is 1863 and two telegraph stations want to communicate. So send out the crews and string the wire! Problem is someone just put the kibosh on using the wire. Worse yet, my ol’ buddy Major Thomas T. Eckert isn’t available to solve the problem, although I am certain he is lurking around somewhere. Alas we
discover that we are really not in 1863 after all, but at one of
to-day's re-creations of 1863. Now that reality has set in, and given that we still want to
show AND USE the telegraph in a reenactment/living history setting, we need a solution that allows the activity to go on and we want to make it look real. Alternatively, we could tell the people who disapprove of us stringing wire to pack sand, but that only results in bad feelings while we are sitting at home watching the grass grow with all our cool stuff piled in the corner. Thus a compromise seems prudent.
The compromise is a system that is wireless but looks and works like a wire is attached between the two stations. That is kind of a tall order considering the nature of the line. While it is possible to hook up radio transceivers to each end to establish a wireless connection, many things need to be considered. To begin with, methods of switching between transmit and receive apart from using the key switch is necessary. The reason is because most radios available are push-to-talk, release to listen thus they require some way of switching from receive to transmit rapidly between the two stations. Elaborate automatic switches can be built, but they may be expensive. That leads into considering full duplex radio communications between two locations. That is, the radio at each end must transmit and receive at the same time. With either case, you also need a device that translates the on-off pulses of a key into something the radio can “hear” to transmit. At the other end, the received signal must be translated back to sounder on and off action. The pesky problem persists of what to do with the key switch that among other things indicates to the opposing operator that the line is ready for transmission. The issues are compounded when you consider that operating our telegraph over radio frequencies may require a license, and in some frequency bands such operation is not allowed. When you further consider that a full duplex radio is really expensive, especially one that has a high duty cycle, the cost of doing wireless telegraph via radio quickly becomes a bridge too far.
Now consider that most of us possess at least one full duplex radio that can tolerate high duty cycles and is called a cell phone. Once two cell phones, AKA radios, are linked, that is one cell phone operator calls another cell phone operator, full duplex communication results. That means we already own one of the most expensive pieces of a system that can link two telegraph stations together wirelessly.
What I am suggesting is not original. If someone has not thought of this before, or is not using something like it, I would be amazed. I have taken bits from the hard work of others and spliced it together. Kind of like what Sam did with Alfred and others. Thus I offer the following:
- Build two of the Trump-Raven 2 Wire Solid State Dial-up Morse Terminals (Schematic)
- Obtain two 300 baud modems, either DCM 3 or DCM 6
- At each station do the following:
Alternative 1:
- Obtain a telephone patch
- Hook patch and modem to cell phone audio (earphone/microphone) jack
- Connect modem to Morse Terminal
- Connect Morse Terminal to telegraph relay
Alternative 2:
- Obtain a Cellsocket
- Hook modem to Cellsocket
- Put cell phone in Cellsocket
- Connect modem to Morse Terminal
- Connect Morse Terminal to telegraph relay
- Use one phone to call the other
- Set one modem to ORIGINATE
- Set the other modem to ANSWER
- Follow the directions related to the Trump-Raven Terminal and start operating!
The entire system operates just as if there were a wire attached. The problems of legality are solved…you are using commercial services. The cell phone charges for most plans when operating wireless to wireless is minimal. If you stuff all the modern equipment in a “period” box, the operation becomes transparent to any and all visitors. What you have built is a cell phone version of the Morse Telegraph Club’s Dial-up Morse using the Trump-Raven 2 Wire Solid State Dial-up Terminal. With the Dial-up Morse system, you can operate at most any code speed accurately using the key lock just as if a wire were attached. Most cell phones pass the telegraph pulses through the audio channels with modems operating at 300 baud. The modems and telegraphy are slow enough that the package passes through the audio circuits unaffected.
Building this system requires some knowledge of electronics. If you don’t have the knowledge or skills, you most likely know someone who can help you. There is some electronic device construction involved. The person doing the system assembly will need to consider several things. Telephone patches are available through internet sources but understand that a great deal of inefficiency may be introduced into the system with a passive telephone patch. The impedance (Z) from the 300 baud modems to the phone system should be around 600 ohms, but you need to consider the microphone and ear phone impedances of the cell phone. Transformers are available to perform the match, but I have successfully used an old amateur radio phone patch even though the Z values where way off. This is a case when brute force can overcome inefficiency if not too much distortion results. If you are a bit clever electronically speaking, it might be possible to get inside the modem, pull off the audio (data) and pass it through some active impedance matching devices for the cell phone microphone and ear phone input and output.
If you choose to use a Cellsocket, you might be stuck with an older cell phone. Cellsocket’s are no longer made and do not support the newer phones which is really too bad because they work well. Using a Cellsocket, the impedance issues that arise when passing the audio through the external audio jack on the cell phone go away. I have a Cellsocket and an older cell phone, and it works great. However, I have used the phone patch audio connection system successfully.
You will need to solve a power production problem. Because of the constant talk time required on the cell phone the power requirements for the Morse Terminal, and the modem, you’ll need to have a constant supply of power at each station. I use a marine deep cycle battery and an inverter, generating 115 VAC 60Hz power for my Morse Terminal, Cellsocket, modem and cell phone charger. I have all that placed in a period looking box. When I am able to use the wire, this same power production system drives the Trump power supplies for my telegraph line.
I recommend anyone attempting this method of wireless telegraph thoroughly study how the Dial-up Morse system works. Then, investigate the availability of the system pieces. The 300 baud modems are getting hard to find. Additionally, you’ll need either a Cellsocket to work with your phone or some sort of a phone patch. Consider that you may need to build a phone patch. There could be a challenge getting the equipment, but it is not impossible. You also need to think about the cell phone charges that are adding up when operating. The telegraph signal goes through the audio portion of the phone, not the data side. Hence only charges related to audio or speech should apply. Talk to your cell phone provider about what you have planned. There may be service related issues regarding your cell phone use with the telegraph that need to be addressed. If you use the phone patch system, you will need to determine what kind of ear phone jack your phone uses. There are at least two types.
I still prefer to use wire. In some respects, it is easier to do. For example, because we usually operate with two stations, we only need one power source. Appreciate that this system will work only if there is cell service to your remote location. That seems to be the case now days, but there could be some areas that do not have service. If you typically do events where cell service is not available, you can resort to the full duplex radio’s I mentioned earlier, but equipment costs rise sharply and there are license/frequency use issues that need to be resolved. The system is expandable. It might be fun to do a hybrid system where some stations are on wire and some use the wireless system. Therefore, it is possible to establish a telegraph communications ring with several stations where wire is not accessible to all areas.
I do not what to suggest that this is an inexpensive endeavor. You will be using a commercial wireless service and will need to construct some electronic equipment. Additionally, you will most likely want to conceal all the modern goodies in a period looking box, something that may need to be crafted. The power production equipment is also commercial in nature and while not terribly expensive, does have a cost. I am suggesting that this is a robust system that fits our circumstances well, and will present a good living history impression. In other words, for us it is an acceptable compromise.
Credit for this idea must go the Morse Telegraph Club and associates. Clearly, Ed Trump and Greg Raven have served as the inspiration for this system. Their offerings related to telegraph operations in a dial-up system or for reenactments should be read by all telegraph reenactors. If you need more information, please see the Morse Telegraph Club web site where construction details for much of the equipment mentioned here is presented.
Rich Dees is the Idaho rep for SCARD. He has been reenacting and doing living history since 1998. Rich is presently the Commander of the Idaho Civil War Volunteers, a living history and reenacting group in Idaho. He has been an amateur radio operator since he was 12 way back in 1957, which he learned the Continental Code. Rich also holds a commercial radio license and have been involved with electronics for most of his life. Morse code is his preferred method of communicating on the radio. Two yeas ago with the help of a Western Union telegrapher, Rich learned (American) Morse. Thomas Eckert is not a relative...Rich just finds him interesting...
