Field phones are one of items that a lot of folks love to talk about but few ever really use. But the fact is that having a set around can be incredibly useful for setting up closed networks to fixed locations. Where field phones really shine in a grid-down retreat, temporary patrol base or guerrilla camp setting, is to network observations posts (OPs). It’s primary advantage over radio is that there’s no electronic signature alerting anyone to your presence- since it’s a direct line from one phone to another, the only way it’s intercepted is if the line is tapped. Most models can be either sound powered or run a very long time from two D Cell batteries, negating the need for a lot of charging equipment. So having that field phone at your fixed positions can be a very good thing. Let’s talk about how to do that.
There’s several models floating around on the surplus market, from WWII & Cold War-era European sets to the excellent US TA-1 and TA-312 and newer. Something to know about the older sets is that while good deals can be had, normally there’s no guarantee to their function, so you might be buying a set only to have them take a dump right out of the box. It is 60-70 year old surplus, after all. Because of this I’ve found the Vietnam and newer-era surplus to be a better deal even if more expensive. I prefer the larger TA-312 for fixed positions because they’re incredibly rugged and simple to set up. Most of the ones you’ll find on the surplus market are in good shape and they’re still being used in some specialized military units. Our commo section had a large stash of them to hardwire hide sites to the communications transmission site in order to keep the electronic signature low. We never needed to do that in combat, but had we been fighting a near-peer war, we would. And because they’re so robust in design, they’re repaired pretty easily if need be.
The older TA-1 is the smallest, lightest and simplest of them all. It’s just a phone handset and a push to talk (PTT) with a cord running to the two post hookup wire outlet. They’re sound powered- no batteries needed. But they are older and not usually as well taken care of as the TA-312 on the used market, so like the older Euro models, I wouldn’t buy one sight unseen. For around $100 on the used market, the 312 is a better bet.
That said, there’s newer field phones out there that are usually much cheaper. There’s a reason. Unless you’re a wizard with telephones, I’d stay away from them. The TA-838 for example, while still analog, was designed for use with a larger military phone network- not point-to-point. Models since then are digital units designed to securely link military posts and are, at least in my experience, more complicated then they’re worth for setting up a simple, local phone network. They’ll have touch tone pads and four wire jacks instead of the basic two. Not saying you can’t make it work if you find a deal on them, but I am saying it’s a lot of extra headache for limited gain. So like always, Keep It Simple, Silly.
Building a network with the field phones is pretty easy. There’s two jacks for dual strand wire; a positive and a negative. Military field wire is known as WD-1 and I’ve found spools of it pretty cheap both in person and online. WD-1 makes good antenna wire too in a pinch. But if you can’t find WD-1 its not a problem- any dual strand wire will work. In the Army I’ve used Claymore wire, which is just aluminum core lamp cord, and I’ve used dual strand speaker wire in private classes when the students asked for hands on with field phones. Match positive to positive and negative to negative and you’re good to go. Can’t get any more simple than that.
The TA-1 and the TA-312 have a ringer to signal the other phones on the line for a call. The TA-1 uses a hand pump and the TA-312 has a hand crank. It’s Joe-proof, meaning there’s no way to screw this up. You can patch several phones together on one common line or have them all linked in series, but organizationally its a good idea to have all of the field phones in the network patched together. Every position now has real time status updates and the person in charge of that shift can call all of the positions at once. If anyone is sleeping on duty, now everyone will know.
What if you end up with a mismatched set? Will they still work? The answer is yes. The TA-1 and 312 work just fine with one another in my experience and the European models will as well. As long as all of the sets are in decent working order and the electrical connections are good, there shouldn’t be a problem. But that said it’s always a good idea to stick to an established standard for equipment.
As robust as they are, there’s no reason for a retreat to have at least one set of them. Even if all you’re doing is networking security positions, they mitigate your electronic signature and provide a very secure means to communicate over short distances. And even though they’re heavy, they can be very useful for a small patrol occupying an area in a patrol base or hide site setting, where you may only be temporarily but will absolutely want to keep a low profile- both physically and electronically.
Want to learn how to set up a communications network off grid using commonly available commo equipment? Wanna know how it all works in the small unit context? Come on out the RTO Course. I have two basic courses on the schedule through the Summer- one in NC and one in Montana with the Advanced Course in NC. What are you doing today to be better than you were yesterday?