What are the choices for off-grid telephony? This article runs through the available options and recommends Spread Spectrum Signalling (SSS).
Imagine the scene you’ve finally gone off-grid, your cosy hut is nestled somewhere rural and beautiful, and you feel really cut off from everything, in a good way. You’ve got the solar panels, a wind turbine and a non-flush toilet, but you haven’t really thought about your communications, have you? You can still have a phone , right?
You could act as your own phone company and lay your own wiring all the way to your house but this is pricey. In some places you can run the wire yourself and the phone company will even supply it for you. They’ll need to inspect what you’ve done before covering it, and make sure the depth of wire placement is appropriate.
Besides requiring permission, technically, the job is not an easy one. You’ll need to have easements established along the path that the wire will follow and a power trencher is a virtual necessity, so you’ll most definitely need to rent or purchase equipment to do the job. Crossing a black-top road will require professional help, and permission is a lot harder to obtain. On the other hand, a private gravel road is less of a technical issue but still a difficulty when it comes to permission. Don’t even try erecting your own pylons if you want to stay in the area.
Moving swiftly onto the less objectionable options
The first alternative most people will consider is cellular telephone service. Since cellular radio does not depend on wires to the customer’s site, there is no big up-front investment in bringing an off-grid customer on line. The standard rate plans, with fairly high costs for each minute of use, have given way to plans that might even be affordable as the primary phone service to a rural property.
Naturally, there are drawbacks to cellular. In some cases the special rate plan may only apply to digital calls. Calls that originate in an (older) analogue-only service area may not be covered. Since the digital system is only in metropolitan areas, it is likely that your service will be analogue, which could impact the cost effectiveness of such a plan very badly.
And remember – a cell phone is just a phone. Cellular modems are not ideal for enjoyable web-surfing – on a very good day you might get a 4,800 bits per second connection speed on a cellular modem as compared to the 33,600 bits per second that is now the standard for hard-wired modems. If you want to be bashing your computer in anger then yes, it’s a very good idea.
But cellular is not the only radio telephone solution. A number of companies provide products called Wireless Local Loop (WLL) systems to provide radio interconnection between telephone central office equipment and customer homes and businesses. These systems are particularly popular in developing countries where telephone service can be provided without installing thousands of miles of wire.
A WLL has two pieces to it – one is attached to the telephone company wherever you can find a telephone wire (maybe your neighbours or a nearby business), and the other end of a WLL system is placed at your house. All it needs is power and a clear line of sight to the other half of the WLL equipment. These two pieces of equipment, one at your homestead and the other attached to telephone wiring, provide a two-way radio link that acts just like wire.
Standard telephones, fax machines, answering machines and computers can be connected at the homestead end and will operate just like they were wired direct to the phone company, almost.
Two different standards are used for WLL equipment. Older systems use lower frequency radio signals around the 49Mhz band. Compared to wire, these low frequency systems are more prone to electrical interference and do not provide nearly as high a data rate for computer communications. A 49Mhz system will perform well for voice, will be adequate for fax and will likely make you impatient when used for computer communications.
Newer equipment is based on Spread Spectrum (SS) signalling in the the 900Mhz band. These systems provide superb signal quality and will support data rates far higher than normal telephone connections allow. A 900Mhz SS system will perform as well or better than any wired phone system and will even support an ISDN connection for the serious data junkies.
Technically, the 49Mhz and 900Mhz systems are somewhat different because of the difference in frequency. The technical differences give rise to different regulations governing the use of these systems. The regulations are in place so you don’t interefere with someone else signal and they don’t interfere with yours.
The 900Mhz equipment that uses Spread Spectrum signalling is inherently a non-interfering technology so the Federal Communications Commission (FCC) requires no licensing or registration of any kind for the operation of 900Mhz SS equipment.
The 49Mhz equipment is a different matter. These systems can interfere with one another and with other authorized uses of the same frequency band, so the FCC requires a frequency coordination within an area. This is done by listening on a range of frequencies and picking one that seems to be unused. This assignment is then reported to the FCC so that others may avoid that frequency in the same geographic area.
Which ever system is employed, there are some common characteristics that will control how the system is installed. Line of sight is one of those important considerations.
A 900Mhz radio signal follows a path that is every bit as straight as a ray of light, so you must have a completely unobstructed signal path: if you can’t see one antenna from the other then the antennas can’t see each other either. A 900Mhz radio signal can’t travel through a tree, which limits WLL to what is termed line of sight. However, you don’t have to be able to see the other antenna with your naked eye. In flat, open country, line of sight is probably about 7 to 10 miles depending on how high a pole you mount the antenna on the higher you go, the farther your line of sight. If you live on a hilltop, you might get 30 miles. So bring the binoculars.
The 49Mhz signal will go through some objects including smaller trees and will bounce off and around larger obstructions, but line of sight is still important if you want a nice clear signal, so it is best to stick with a clear path if you can.
The least attractive feature of WLL systems is the cost. A dual line system will cost anywhere from $4000 + depending on vendor, model, and installation issues (like range). But, compared to the cost of running wire which costs around $1 /foot even a one mile run could exceed the cost of a WLL system.
DIY your WLL
This option is not for the faint-hearted (or for those who don’t have a good technical knowledge of the equipment).
Start with a 900Mhz SS wireless telephone from a phone store, some of which have a pretty good range. One such phone has a measured range of a couple miles. The idea is to put in a better antenna for both the hand-held unit and the base station to have a WLL solution capable of several miles.
Even if a better antenna did not improve range, you still need an external roof mounted antenna to get good line of sight.
The base station for the phone would be placed where it had access to the telephone line and the handset would be located at the homestead. Since the charger is usually part of the base unit, you might need two complete phones (using one of the base units solely to charge the handset).
You’ll need to replace the antennas with directional antennas that will then be aimed at each other. [Note: this probably violates FCC regulations as the equipment is certified for the particular antenna it comes with, but as long as it causes no interference it will never be known.] Hacking the antennas into the base and hand unit would require a bit of radio skill but the parts would be very cheap.
This sort of arrangement would work for voice-only connection. It’s a very inexpensive approach, well less than a thousand dollars.
For data connection, things get more complicated.
There’s something called Voice of IP (VOIP) which is where you transmit voice communications over Internet Protocol (IP), the way computers communicate on the internet. If you had two computers, one at home and one at a telephone connection, you could transmit voice between them if they were connected with a computer network.
With a radio modem you can do just that. There are several plug-in cards for PCs that allow two computers to be networked together without wire radio spans the gap where wire is normally used. You then add a telephone interface card into each computer and enjoy a wireless internet connection and a standard telephone interface in one unit.
Any standard telephone can be plugged into the telephone interface card and used just line a hardwired phone. Including a pair of directional antennas, such a system costs about $2000 at current prices.
Once you have the telephone interface cards, you can also make use of the internet long-distance telephone companies. These work just like the long distance phone companies except that the calls are routed, for free, across the internet.
Appealing as it sounds, building your own WLL system is very involved technically, and certainly isn’t for everyone. Basically, it just depends on how good you need your signal to be, whether you’ll be ok with just voice calls, and what your budget is. Buying a WLL unit off-the-shelf is a perfectly acceptable solution for most homesteads. You have been warned.
To help you on your way
If you’re after emergency communication tips, the book Survival Communications is good for anyone interested in emergency preparedness. Nothing on normal phone services though. Available at Amazon for $19.95.
Rural Telephone and Internet has just about everything you need to know to make phone calls over the Internet. A very good tool, because over the internet long distance is free, or nearly so, and an Internet connection may actually be easier to get than a phone line. The CDROM included with the book has some useful software. Available at Amazon for $23.96
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