Things that Work! Home Power tests the Telemobile Radio Telephone System We had a problem here at Home Power/Electron Connection Central. I emphasize the word "had" because we don't have this problem anymore. Instead we have a telephone. The situation was critical. We were trying to run a publication coordinating over 8,000 readers and 40 advertisers nationwide without a telephone. Our site is far too far from any sort of hardline. Instead we opted for a dedicated radio link to bring telephone service to our remote location. And it works. Radio Telephone (R/T) Overview The Telemobile R/T system interfaces between the regular telephone line and a remote site via two way radio. One section of the system is connected to a standard telephone line at a location where telephone service is readily available. This base unit then talks to the remote unit via radio. The remote unit has no actual physical connection to the base and may be located up to 15 miles away. The system is full duplex, meaning that you can both talk and listen at the same time. Operation is identical to a regular hardline telephone and most callers in don't know there is a radio link in use. Physical Examination The Telemobile system consists of two black boxes each 4 inches high, by 7.3 inches wide, by 12 inches deep. Connections are provided for power (either 120 vac or 12 VDC models are available), radio antenna, and a standard jack for a telephone plug. I opened the cases of the Telemobile R/T and found high quality printed circuit boards jam packed with radio components. The quality of the components and construction appears excellent. The documentation in the owner's manual is quite skimpy, limited to installation and operating essentials only. Fortunately, Jim Carlson provided us with the factory service manuals which are very complete. Test System We installed one end of the system at the business telephone line we had at Stan Krute's Hacker & Nerd Centre. This location is about 4 airline miles from us and has buried phone lines nearby. Power at H&N Centre is 12 VDC via PV panels and batteries. The antenna used on this particular UHF (ultra high frequency) system is a 12 element yagi type with a boom length of about 3 feet. The antenna is mounted on a 36 foot telescoping mast and fed with heliax coaxial hardline. The other end of the system is located at Home Power Central. A yagi antenna of 8 elements is on a 36 foot pushup mast. This end is fed with RG-213 coax. The remote here at HP Central is also 12 VDC powered via PVs and batteries. We had extensive installation help from Jim Carlson of Carlson Electronics. Not only was Jim able to specify our system using topo maps, but he also came to our site and got the whole thing working! He also obtained the necessary FCC licenses for the system. In this day of mass merchandising, it is unusual to find a group willing to provide personal service, thanks Jim. System Operation It works very well indeed! The Telemobile's operation is totally transparent. It operates just like a regular telephone. Pick up the handset and dial. When you're done just hang it up. No special codes, radiotelephone operators, and none of the vagaries we have come to expect from radiotelephone systems. The quality of the FM (frequency modulated) audio is excellent. Our UHF system maintains constant communication over a less than ideal path. You see, even though the radio path between the units in our case is short, it is NOT line of sight. We shoot through, around, or maybe even over several large hills with our radio signal. And it still works reliably. The Telemobile system doesn't come with a telephone handset. And this is an unusually nice feature as it allows you to use virtually any piece of standard phone gear in the system. Most R/T system offer only their built in phone. Telemobile R/T systems will operate regular, off-the-shelf, telephone equipment such as answering machines, cordless phones, or even a Mickey Mouse phone. The power required by this ancillary phone equipment is produced inside the Telemobile black boxes, where 12 VDC is converted into Å40 VDC for the phone equipment. We like this unique feature as it contributes to the flexibility and transparency of the system. The systems receivers (both operating all the time at both ends of the system) consume about 40 Watt-hour per day each. The transmitters consume about 155 Watt-hours per day each with our fairly heavy phone use. I figure that the power for the system can be produced by two 48 Watt PV panels, one at each end of the system. The Rules of the Game These systems are FCC licensed. This is best left to the folks selling and installing the system. There are literally yards of paperwork in triplicate. The FCC only wants to license business or other official type organizations. Seems individuals don't countÉ Well get organized or businessed or whatever it takes to make the license legit. Jim Carlson can be of invaluable help in the licensing procedure. Nuff said. The telephone line is a regular type line. The phone company adds NO additional airtime charges as they do with their proprietary IMTS radiotelephone systems. The user owns all the equipment, and once it's paid for, that's it. No large disturbing monthly bills from Ma Bell, as the phone is billed just like any regular telephone. You must have a radio path to make the system work. There are limitations involved with radio communication. For example, the R/T antenna here at HP Central was blown off course during a heavy wind storm. The resulting antenna misalignment caused our system to be unreliable until I discovered what the problem was and set the antenna straight. The distance, terrain and weather are all factors that can affect an R/T system's performance. Because every situation is different, Telemobile makes several different models of their R/T system. Some are long range VHF models, while other are shorter range UHF models. It is best to seek the help of someone adept in R/T system to find out what system best meets your needs. TestingÉ TestingÉ We are still evaluating this system. We are planning on running computer data via modem over the Telemobile R/T. We also want to try it out with a FAX machine. Both these projects are on the back burner until this copy of HP is in your hands. According to Jim Longnecker, the R/T Techie at Carlson Electronics, the Telemobile is capable of 1200 baud modem transmission and FAX service G2. If you want to hear a Telemobile unit in action give us a call at Home Power/Electron Connection Central (916-475-3179). We've had the Telemobile R/T system working for about 3 months now. The initial black boxes we installed proved to be escapees from the factory quality control line. The remote had very low outgoing audio and everyone we talked to complained we sounded distant. Jim Carlson rushed us a new set black boxes, but these were properly tuned. The new black boxes are in place now and the audio is fine. Jim assures me that all R/Ts leaving his shop are now checked for tuning and performance before they go out the door. Once again, service like this is hard to find. Cost The cost of these systems vary with the type required. A typical system will consist of 2 transceivers, 2 antennas and 2 feedlines. It will cost in the neighborhood of $3,500. The user supplies the masts (about $60 each), and sees to the installation of the telephone company's hardline. The vendor (in our case Carlson Electronics) takes care of the specification, installation, and licensing of the system. While this is not cheap, it is much cheaper than any alternative available to us. The telephone hardline would have cost over 10 times this amount. Simplex RCC R/T services, with their multiple users and operators, were not suitable for business use. We had already tried the phone company's mobile service (IMTS) for over two years and found it super expensive. IMTS gear is initially cheap, but the phone co. charges about a buck a minute to use their repeaters. With only minimum usage, the IMTS system yielded us phone bills in the $400 to $800 per month range. At that rate the one time initial investment of $3,500 for a Telemobile system would pay for itself in less than a year. Conclusion The Telemobile radiotelephone system is a working solution for back country phone communication. The system is reliable, easy to use, and far less expensive than installing a hardline. It is very user friendly and indistinguishable in operation from a regular telephone. The Telemobile system accepts standard telephones and off-the-shelf phone accessories. Since the user owns all the hardware, the system is billed by the phone company as a regular telephone. Power consumption of the system is very low, making it a natural for use in remote renewable energy systems. Contact Carlson Electronics at 774 Redwood Drive, Garberville, CA 95440 or call 1-800-283-6006 or 707-923-2345. The system's manufacturer is Telemobile Inc., 19840 Hamilton Ave., Torrance, CA 90502, or call 213-538-5100.