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The Hummer Knowledge Base
Accessories/Communications/Cellphones/High-Gain Antennas:
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Several people have asked where to order the directional cellular antennas.
Any reputable communications store should carry these. The local shop here
in Santa Clara is County Communications at (408) 244-4750. Ask for Nick.
They can also custom make a cable to go from the Type-N connector on the
antenna to your cellular phone. Be sure and specify the connector on the
phone (Motorolas are typically Mini-UHF and most others use TNC).
County Communications also sells high quality VHF commercial radios at reasonable prices. They have the frequencies assigned to the Hummer Owner's Association on file and can program and ship the radio to you. Everett Fred Basham
In response the Everett's story about using a Yagi cell antenna, Jack said: This sounds fantastic. Where can I order one of these antennas and what do I ask for? Jack Rickard
Well, this is the kind of thing I have been doing for a living for the past few years, so let me share. About the best antennas for this are made by Sinclair Technologies of Tonawanda, NY. They make several: First is the SRL-406, which is a Yagi antenna (looks sort of like the log-periodic antennas used for VHF-TV only much smaller) with 10 dBd gain (that is 10 dB over a dipole antenna). Three watts is the maximum power from a cellular phone, so 10 dB gain boosts it to 30 watts maximum Effective Radiated Power (ERP). Of course, power reduction will still work so the Cellular Base Station may still turn your phone's power down. It is 24 inches long by 6.4 inches maximum width. List: $196. The next antenna is the SRL-406, which is a similar antenna, except it is 12 dB of gain, which will improve the ERP of the 3 watt phone to watts. It is longer, 37.5 inches and the width is the same. List: $286; and $100 is too much to pay for 2 dB. There is a problem with using high gain antennas for cellular. If the cellular system, or even two systems hear your Electronic Serial Number (ESN) and phone number (with other stuff the NAM) at the same time, at cellular base stations that are not close together, they assume your phone has been cloned. This assumption is held more strongly if you are away from your home system ROAMing. If the system sees this, it will automatically shut you down. You will have to talk to your home service provider to get your phone back on and that typically takes a day or two. In the mean time, you will be forced to use a credit card, not a phone card but MasterCard or Visa, in order to use your phone. This is a problem because the whole area can hear every word you say on your phone, so some not so nice guy can get your card number and go off on a shopping spree. Yagi antennas put MOST of the signal in one direction, but they put some in many directions, especially behind the antenna and are more likely to be sniffed and shut down. There is an antenna that does not send signal in but one direction, though it is bigger than a Yagi because it will not lie flat. It is called a Corner Reflector. It is a "V" shaped metal plate with the driven element in the "V." The Sinclair SRL-402 is such an antenna. The gain is 10 dB, same as the first Yagi, but it puts almost no signal behind it, in fact it is all in a 180 degree arc in front of the antenna, with the signal at 90 degrees being about 24 dB below the maximum. This antenna is much more likely to not be "sniffed" and therefore your phone will stay on. Don't say it cannot happen, I have seen it happen between systems in New Jersey and West Virginia! What a problem having no phone. This antenna will fit in a two foot square box. List $509. One last antenna, and I hope you will never need it: SRL-460. It is a partial parabolic dish, kind of like for the Dish Network, or Primestar, except they are "cut down" to be rectangular. It is 48" wide by 24" tall. The driven element sticks out from the middle by about two feet, and may be removed for shipping or storage. It has 15 dB gain and is expensive. List: $1,041. I am a dealer for these, and about every other brand of antennas, and I recommend Sinclair over all others. They are nearly indestructible. I recommend you call the factory direct (800-228-2763) and tell them you are a ham and would like a 25% discount. DO tell them it is for Cellular, so you get the proper frequency split. With any extended range system for cellular, or practically any radio system, height is important. You will want some kind of mast to get the antenna in the air. This can be 2" or so diameter pipe, and some way to get it to stay vertical. BUY THE PIPE AFTER YOU GET THE ANTENNA so you can get the proper diameter for the clamp on the antenna. Broadcast suppliers have a push up mast. You drive onto a plate that has a socked in it. Put the mast, which is about five feet long when nested, into the socket, and attach the antenna. You then push up the inner-most nested section and lock it in place. Then push up the next section. When you are done, the antenna is 25 or 30 feet in the air! All this for only about $1,800! Call Kathleen Karas at 800-955-6800. Tell her you will pay with a credit card, you may get a better price. I have used these things too, and they work great! Not as well as a pneumatic mast permanently mounted in the truck, but well. If you go the latter route, pneumatic masts can be gotten up to about 120 feet. If you can't find cellular service at 120 feet, you need a short wave communications system, not cellular. There is a system that I think is called Satellite Cellular. It uses a cellular like phone and an antenna that looks like a football, but is a bit larger, or an antenna that is about 40 inches tall and four inches in diameter. The phone costs about $3,600 and may include cellular as well. If you get everything from them, you will pay about $3.00 per minute while on the bird, and less than $1 per minute on cellular, depending on where you are. They have roaming agreements with cellular carriers all over the US, and must of North America. It checks for Cellular first, and if service is there, that is the way you go. If there is no cellular service, you go to the bird. The company is here in the Washington area, I believe in Arlington, VA. Good luck, and go get lost. |