CHRIS%BROWNVM.BITNET@MITVMA.MIT.EDU (Christopher Chung) (09/06/88)
I am look for the longest range cordless phone I can get. Does anyone know what the longest range that is possible or exists? Who makes it and where can I get one? I would like to use it in a building but the problem is that there is a lot of steel and computers. We have tried a 1000 foot cordless and that almost does it. I think one that is a little stronger will just fit the ticket. Anyone know where I could get one to try? Chris
john@rutgers.edu (John Kurzman) (09/14/88)
A request was made for a cordless phone that could go a long distance (1000 feet almost made it). Megatronics International sells cordless phones with ranges from 3 miles to 40 miles! They are not for use in the U.S. These are not cellular phones. They would compete with Cellular in the US if they were legal here. They give you wide range for your own phone number without extra $ to the phone companies. FCC wouldn't be too pleased either. Ham operators can also get an attachment for their phone line so they can 'ham' to their phone (or vice-versa). A friend of mine used his from the LIRR moving train to his home >30 miles away with no problem. (But he had a license) The key ingredient in finding a long range cordless phone is legal issues for the radio transmission. The technology clearly exists. COMB had a long-range phone (greater than current legal limit) in their catalog for a while about a year or so ago.
cy@pnet51.orb.mn.org (Cyril Bauer) (10/28/89)
How about an alternative? I saw someplace a jack that a person cold
put into the a.c. power. Transmission takes place over the a.c. line
along with the supervisory commands for on and off hook. I don't know
how well it works or if and where you can find it. I'll look around in
the books that I have and leave another note on here when I find it.
This is if you so desire. Paging could be done with the ringback
feature in your area if the telco allows it. Otherwise another device
could be added with very little cost using the f.m. over the power
lines too.
UUCP: {amdahl!bungia, uunet!rosevax, crash}!orbit!pnet51!cy
ARPA: crash!orbit!pnet51!cy@nosc.mil
INET: cy@pnet51.orb.mn.orgtad@ssc.UUCP (Tad Cook) (10/30/89)
In his posting, Cyril Bauer talks about a system using carrier current transmission on the power line for telephone extensions. Although this can work, there are a couple of problems with this. One is with all of the powerline noise filters and spike blockers that we have on our computers and electronic gear now. The ones with just an MOV are not a problem, but the better quality ones with filtering act as a big bucket for all the RF. Another problem is that power wiring at a premise is divided between the two legs of the 220 VAC line. A signal transmitted on one leg wont go to the other very well. One way around this is to hook a cap between the two 220 VAC legs at the service entrance to couple the signal between the two legs. One mod that may work with the noise filters is to put series inductors between the noise filter and the line. This would present high impedance to the RF. Many noise filters already have inductors, but if there is a capacitor on the line side, there would still be a problem without external inductors. Tad Cook tad@ssc.UUCP