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Mar 202013
 
A classic US military TA-312A/PT Field Phone.

A classic US military TA-312A/PT Field Phone.

As we’ve discussed in our article ‘Will there be telephone service after TSHTF?‘, it is probable that any event such as to activate your prepping survival plans will see a loss of both wired and wireless phone service.  We also predict the same failure for internet service, for similar reasons.

This will make your retreat electronically cut off from the outside world.  Oh – with the likely shortage or total disappearance of diesel and petrol supplies, you’ll become more physically removed from the nearest township too.

There will remain methods of communication, which we’ll discuss in subsequent articles in this series (particularly ham radio, and we’ve already advocated you should get a ham radio operator license) and of course other methods of transportation (or of fueling your current vehicles) too.  But this article approaches one of the alternatives you have for communications in, on and around your retreat property.  Using Wired Phones.

The Pluses and Minuses of Using Wired Phones

Apart from smoke signals, semaphore, and other ‘low bit rate’ forms of signaling, most of your communications around your retreat property would be either by wireless telephony of some sort (CB or other walkie-talkie, ham radios, Wi-Fi devices or cell phones) or by wired phones.

As we never tire of saying, you need to plan for a low-tech ultra-reliable type of communications that you can be certain will survive any initiating events that plunge you into a Level 2/3 situation, and which will continue to operate during the period of that situation.  As lovely as wireless devices are, they are less resilient.

There is another downside to wireless communications.  They are more readily detected and monitored by unfriendly people.  What is the point of being obsessive about ‘Op-Sec’ in a dozen different ways if you are chattering away on walkie-talkies regularly every day, providing a huge big electronic ‘homing beacon’ for unfriendly people to zero in on.  With scanning radios nowadays being inexpensive, readily available, and easy to use (for example, the $100 Bearcat handheld scanner listed on the many pages of scanners at Amazon, here) you have to assume that any radio transmissions you are emitting will eventually be picked up by people who may not have your best interests at heart.

Wireless devices also need batteries.  Sooner or later, you are going to run out of batteries, and/or your rechargeable batteries will wear out.

In comparison, wired phones are much more secure and harder for unwanted third parties to eavesdrop and listen in on.  They are generally lower tech and probably are more likely to be repairable if they develop a problem.  They might also require power, but they are probably much more forgiving about the type of power and the exact voltage they’ll operate with than is the case with a wireless device.

But a wired phone is not something you can have with you, all the time, everywhere you are located.  You need to have wiring run to each place a phone is placed.  And the wires are somewhat vulnerable to accidental or deliberate damage, although it is true your radio signals could also be deliberately jammed (all an enemy would have to do is to transmit on the same frequency as you any time you started a transmission, which might cause your transmission to be displaced by his).

Overall, if you are asking yourself the question ‘Should I prepare for wired or wireless communications at my retreat?’ you are probably not asking the correct question.  Ideally, you should have both.  Where possible, you’d use wired communications, but also have the ‘safety blanket’ of a wireless device with you for emergency communications.

Note that emergency communications might occur from you to other members of your retreat community, or equally likely, in the other direction from them to you.  Emergency communications don’t only involve ‘Help, we are being attacked’ type scenarios.  There are plenty of other emergencies and high priority reasons for calling someone else, and many of those scenarios won’t see either you or the person needing to contact you being at a wired phone.

So in the balance of this article, we look at issues to do with a simple type of wired phone – the field phone.  We’ll also be publishing articles on other communication options subsequently.

What is a Field Phone?

There is no formal definition for what a field phone is or is not, other than a vague expectation that it is a rugged device and probably of military origin.

When we talk about field phones, we are referring to very simple basic analog phones, although note that the latest military field phones are sophisticated digital devices.  There is nothing wrong with these at all, but they require more support and high-tech infrastructure than very low tech analog devices and from a prepping perspective, we are best advised to keep it as simple as possible.

The simplest phones of all require no power of any sort – no mains power, and no battery power either, because they are sound powered.  Slightly more sophisticated field phones are battery-powered, either from batteries inside each phone set or by batteries at a central switching location.

Field phones are connected to each other and to switching points via ordinary wire (rather than coax cable).  Some phones use two wires, others use four wires.  Two wire phones are typically a ‘simplex’ type of operation where only one person can be speaking at a time (like using walkie-talkies); four wire phones permit ‘duplex’ operation with both people speaking simultaneously.

Field phones are generally not equipped with dial pads and generally are not connected to any type of automatic switching exchange.  They certainly could be equipped with such capabilities, and be connected through an automatic exchange too, but as the sophistication of the phones and the required ‘central office’ support equipment increases, we feel we are no longer talking about ‘field phones’ which, by definition, should be thought of as very simple devices with limited capabilities.

There is no reason why you couldn’t create your own automated private exchange if you wish to do this – there are plenty of ‘off the shelf’ systems that you can buy for varying amounts of money, and with varying features, and you might validly wish to add a small private exchange to your retreat as well.

But the more sophisticated you make your communications, the greater the vulnerability they present.  They become more maintenance intensive, they become more energy intensive (requiring good quality electricity) and they become more EMP-vulnerable (phone lines will act as antennas to funnel and magnify EMP energy into the phones and other devices they are connected to, making phones and phone switching equipment very vulnerable to EMP effects).

There is also no reason why some field phones could not be connected – either directly or through your own branch exchange/switch, to the public phone network as well.  But you’re running into the danger of ‘over-engineering’ your situation and your solution.  Field phones are designed to be simple in form and simple in function.

At the other extreme to the latest multi-feature digital phone, you end up with a sound-powered phone.  Sure, it does nothing other than transmit voice to another person, but there’s almost nothing that can go wrong with it, and the few things that might go wrong can generally be repaired without any specialty high-tech tools, equipment, or parts.

Some things are common for all field phones – especially issues to do with how you wire them.  We consider these issues in this article; in another article we talk about the different types of field phones you can choose between.

Wire for Field Phones

Unlike wire for data or radio frequency circuits, field phone wire doesn’t need to be shielded, and doesn’t require any other special properties.  It just needs to be insulated and suitably strong for however you’ll be laying it.

Field phones can operate on pretty much any type of electrical wire at all.  The larger the gauge of the wire, the less the resistance and the longer the distance you can have between phone sets, especially with sound-powered rather than battery-powered phones.

The ‘entry level’ least expensive and arguably most common type of wire for military field phones is the WD-1/TT or WD-1A/TT single pair multi-strand wire.  It is lightweight and inexpensive, and you can sometimes find it for sale on quarter mile or longer reels.  There are also plenty of other types of mil-spec wire (with better conductivity, but greater weight and higher cost) and there’s no real need for the wire to be mil-spec anyway.

Four Wire vs Two Wire

If money allows, whenever you run one wire, run two or three, because you’ve no idea what you might not want to have in the future, and it is very much easier to run multiple wires at the same time than it is to redo the whole exercise and run more wires later.

In the case of  phone wiring, this means that even if you’re only planning on using a single wire pair type phone system, you should still make a point of running two pairs or four pairs of wire everywhere.  Who only knows what you might not end up using the additional pairs of wires for – you might upgrade your system to a four wire phone system, you might use the wires to run some power, or for remote metering, or who only knows what else.  Or maybe one of the wires breaks and you can then switch over to another spare wire.

Of course, it is one thing to be running multiple pairs of wire over short 100 ft distances within your retreat.  The extra cost is minimal.  But if you’re running a one mile line from one end of your property to the other, or a five mile connection to your neighbor’s retreat, then the cost of doubling up on your materials becomes more appreciable and you might have to compromise between what would be ideal and what is feasible.

Comparative Efficiencies of Different Wire Types

The length of wire you can run is limited primarily by the resistance of the wire.  Resistance is determined by the type of material, the thickness of the wire, and the length of the wire.

In general, copper is the best conductor of electricity (ie it has the lowest resistance), with aluminum as second best, then iron, then steel.  If copper has one unit of resistance, then aluminum has about 1.6, iron has about 6, and steel has about 8.5 units.

To put that another way, for every 8.5 ft of copper wire, you can only have one ft of equivalent thickness steel wire; or for every 1.6 ft of copper wire, you can have one ft of aluminum, and so on.

Another way of looking at it is that to have the same resistance, you must have a steel wire nine times thicker than a copper wire, because the larger the thickness or diameter of the wire, the better the conductivity.  On the other hand, the thicker the wire, the heavier it is, which poses problems if stringing it up between poles, and adds to its cost, no matter how you are running the wire.

Several different sources list comparable effective distances for TA-312 phones depending on the type of wire they are being connected together with.  The same concepts apply to other phones too, of course, such that if a phone’s range with one type of wire is twice as long (or twice as short) then it would be similarly twice as long/short for the other wire options presented as well.

Here’s the table for TA-312 phones (source – alas, the company that lists the phones no longer makes/sells them – I checked in March 2013).  As you can see, the practical working distance lengthens dramatically as the wire thickness increases.

WD-1/TT –  35 Km (22 miles)

Lead Covered Cable (19 Gauge) –  48 Km (30 miles)

Open Wire Line (W-2 #14 AWG copper, 0.064″ diameter) –   370 Km (230 miles)

Open Wire Line (W-74 #12 AWG copper. 0.081″ diameter) –  837 Km (520 miles)

How to Run Your Field Phone Wire Outside

Wiring for inside your retreat is a relatively trivial issue.  You’ll probably have it in the walls and ceiling and terminating in wall jacks, just like for regular phone and data wiring.  But how you run your wire outside is a more complex consideration.

The first consideration is security.  If you don’t want your wire to be obviously exposed, then you’ll almost certainly have to bury the wire to obscure and protect it.  An exposed wire poses several security threats.  First, it could be damaged/broken.  Second, it could be followed, perhaps helping an unfriendly visitor to locate any remote observation posts you might have.  Third, it could be tapped into, allowing unknown parties to listen in on your conversations.  And fourthly, a person might connect a high voltage device in series or parallel with the line, probably destroying whatever devices were connected at either end.

So, for security purposes. a buried line is better than an above-ground line.

Buried lines can be both more vulnerable and less vulnerable to accidental damage.  There is a risk of someone digging through the line, or perhaps as part of plowing a field also damaging the line.  Gophers and moles can be a problem, too.  Over time, tree roots may damage lines.  If a buried line is damaged, it can be more difficult to locate and repair the damage that with an above-ground line, unless you have a sophisticated test device that will tell you the approximate distance to where the line damage is located.

If you are running below-ground wire, you don’t need it in conduit, although that would enhance its protection appreciably, and so if budget allows, we would recommend you to do so, and particularly if you anticipate potential mole/gopher type challenges.  We suggest that one way to protect below ground wire – and to conveniently locate it again if you need to – is to run it alongside fence lines.  Usually any plowing or other working of the ground doesn’t go hard up to the fence line, so your wire is more likely to be undisturbed.

On the other hand, above ground lines are far from bullet-proof, either.  Indeed, there’s a vulnerability in that expression – there’s a danger of idiots capriciously or maliciously shooting at your lines just for the fun of it.  Depending on how you are keeping the lines above ground, if they are strung from tree to tree, you have obvious problems in the wind.

The only good thing about above ground wires is that it is easy to trouble shoot them and to repair them if (when) they break.  Generally we recommend below ground wiring.

If you have below ground wiring, we’d suggest that, where appropriate and possible, you either have inspection and access traps to allow you to easily access the wire or simply run the wire up above the ground on a post then back down below ground again.

If you run the wire in direct lines between traps or posts, that will help you follow its path if you need to dig it up to repair it in the future.

The traps or posts also provide access points where you can connect phones.

Fencing Wire for Field Phones

If you have a wire fence, why not use the fencing wire to carry a phone signal, too?  That is certainly an option.

Typical fencing wire is made out of zinc coated steel, and is 12 – 12½ gauge in diameter.  A 500 ft length of 12 gauge copper wire has a resistance of 0.77 Ω, a similar length of steel wire has a resistance of about 6.6 Ω (source).

Or, to express it another way, the resistance you’d encounter with 100 ft of WD-1/TT wire would be about the same as you’d encounter with 140 ft of fencing wire.

Using fencing wire for your field phones also has the advantage that you can tap into the circuit any time you are close to the fence line.  It is semi-secure, being ‘hidden in plain sight’.

If you were going to do this, then assuming you have a more than two wire fence, we’d recommend connecting the top wire and the third wire together for one part of the phone two wire pair, and the second and fourth wires together for the second phone wire.  Every so often, you should run wires connecting the electrically twinned/joined together fence wires.  This makes the double wiring more fault tolerant.

Doubling the wires this way not only halves the resistance (so then 280 ft of doubled fence wire would be the same as 100 ft of WD-1 wire), but also gives you some redundancy – one of the two wires can break and the other one still remains in place.  And by using only the top wires, the bottom wire (in a typical five wire fence) is left untouched, with this being the one most likely to be contacted by grass and other vegetation that might otherwise cause some of the current to ‘leak’ out.

If you only had three usable strands of wire, we’d recommend that about half the time, the third wire be linked to one of the two wires and the other half the time, it be linked to the other of the two ‘main’ wires.  That way it gives you a reasonably balanced/averaged resistance on both sides of the two wire line.

We would recommend using the middle wire as the one which alternates between sharing the signal with the wire above it and the wire below it.  That way, if you wanted to connect a field phone up to the fence wires, you always know to use the top and bottom wires and to ignore the middle wire.  It doesn’t matter if it is sharing the top or bottom wire, wherever you are.

Clearly, if you came to a gate, you’d then need to have ‘normal’ wire running down from the fence posts, under the entrance/gateway, then up the other side again.  And anywhere you had joins in the wire, you’d want to make sure the two lengths of wire had plenty of contact between them to create a good electrical connection.  In general, it would be preferable to run your fencing with as few joins as possible.

Wiring Topography and Strategy

There are several considerations and different ways to run your wiring.  In its simplest form, you have a simple single pair line running all around the place, and you can connect phones on and off this single pair line anywhere you want to, any time you want to.  Simple sound powered phones will get quieter and quieter for each extra phone currently connected (in parallel) across the wires, so that is a limitation, and there is a similar (but not so severe) type of limitation for battery-powered phones too, but for a quick and easy initial wiring layout, this works just fine.

If you have multiple phones on the one circuit, then anyone can pick up their phone and hear what other people are saying, and there has to be some sort of signaling protocol so a person calling another person can make the call request in a manner that doesn’t cause everyone to simultaneously rush to pick up their phone, only to find that the call wasn’t for them.

There is a variation on the single length of circuit concept, which is to make it into a loop.  This makes the circuit fault tolerant – you can have a break in the loop occur somewhere and the circuit will still work because the current simply flows the ‘other’ way between the devices.

This also makes a nice way of managing your circuit – you can have a test point on each of the two wires that is a break in each wire.  Normally you have the breaks joined together, but you can open up the test point and check for continuity/resistance in the circuit.  You’d get a very different value if a break in the line had occurred than if the line was still okay in both directions – although note that this value will vary depending on how many phones are also connected in parallel across the line and where they are located.  Best to do the test with as few phones across the line as possible.

A more sophisticated system has a star type of shape.  A central point – somewhere in your retreat building, probably, has multiple lines feeding out to different locations, with phones being connected on these multiple lines.  When someone calls on the remote phone, it rings at a switchboard in your retreat, and when someone answers, they can then either talk to the caller or connect them to one of the other phones if the caller wished to be switched to another person on another circuit.

The benefit of this type of system is that you can have multiple conversations simultaneously, and happening separate to each other, rather than having everyone simultaneously using the one circuit and struggling to get a word in edgewise.

In reality, you’re probably not going to have – or need – an extensive phone network.  You might have one phone in the barn, a ‘traveling’ phone that people can take with them when they are working in the fields, maybe another phone as a ‘gate phone’ that visitors can use to call to you at the retreat from your property boundary/gate and ask for permission to enter, and maybe another phone in an observation post.

Summary

Good and convenient communications simultaneously become more essential and more difficult in a future ‘grid down’ situation.  They are more essential because you need to live your life more efficiently, and good communications is an essential part of coordinating your life and your activities with those of the other people in your community.  Good communications are also an essential part of your retreat’s security program.

But the ‘grid down’ nature of a future Level 2 or 3 situation means you have to provide your own solution to your communication needs.  We recommend you adopt both wired and wireless communication services, and in this article we have given you some of the information you need to install a wired field phone type system.

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David Spero[suffusion-the-author display='description']

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