"John T. Grieggs" <grieggs@jpl-devvax.jpl.nasa.gov> (08/17/90)
I recently acquired an AT&T portable phone. I do not recall the
specific model number, it is the one with two switchable channels.
The problem is that the signal quality degrades rapidly, even within
the house. Two rooms away, people who talk to me complain about the
signal quality. I get crackles and pops, and sometimes some crosstalk
(although never clearly), as well as a pretty high level of hiss.
This is maybe twenty feet or so from the base station. Also, when I go
anywhere near the computer room, it gets much worse still, to the
point of being un-usable.
How can I boost the power of the phone?
Is there some modification I could make to the phone or the base
station to increase the signal strength?
Would a longer/better antenna on either the base station or the phone
itself help? If so, where would I get such a beast?
What about the interference? Would more signal strength help punch
through this? Or, should I be looking at a line filter of some sort
for the computer itself?
Any help would be greatly appreciated.
John T. Grieggs (Telos @ Jet Propulsion Laboratory)
4800 Oak Grove Drive, Pasadena, Ca. 91109 M/S 301-320T (818) 354-0871
Uucp: {cit-vax,elroy,chas2}!jpl-devvax!grieggs
Arpa: ...jpl-devvax!grieggs@cit-vax.ARPAJohn Higdon <john@bovine.ati.com> (08/18/90)
"John T. Grieggs" <grieggs@jpl-devvax.jpl.nasa.gov> writes: > I recently acquired an AT&T portable phone. > [Complaints about noise and signal quality.] > How can I boost the power of the phone? > Is there some modification I could make to the phone or the base > station to increase the signal strength? > Would a longer/better antenna on either the base station or the phone > itself help? If so, where would I get such a beast? It seems that about twice a year these questions come up. First, your cordless phone is not a cellular phone; it has some distinct and serious limitations. It is amazing how many people expect cordless phones to be perfect. Cordless phones fall under two sets of rules: Part 15, which covers the RF part of the phone; and Part 68, which addresses all the normal phone/network stuff. Any tampering with the transmitter in either the hand unit or the base will render the Part 15 certification null and void. This also applies to the antenna, however since the antennas are already optimized, tampering with them generally simply results in degraded performance. > What about the interference? Would more signal strength help punch > through this? Or, should I be looking at a line filter of some sort > for the computer itself? This isn't the answer you want, but sometimes an environment isn't suited for a cordless phone. While the Ministry of Information won't cut a hole in your roof and haul you away in a straight jacket for modifying your scanner (receiver), the FCC can sometimes get nasty about unauthorized modifications to devices that EMIT RF in normal operation. Cordless phones run at the limits prescribed; increasing anything on them is an FCC rule violation. BTW, 25-30 feet is about all you can expect from a cordless phone in an electrically hostile environment, such as the one I have here. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@bovine.ati.com | San Jose, CA 95150 | M o o !
irv@happym.wa.com (Irving Wolfe) (08/19/90)
In <11015@accuvax.nwu.edu> john@bovine.ati.com (John Higdon) writes: >BTW, 25-30 feet is about all you can expect from a cordless phone in >an electrically hostile environment, such as the one I have here. He doesn't know how lucky he is, or how bad Panasonic cordless phones can be despite the quality of their other phone equipment. Mine starts becoming a little noisy at five feet and is about as noisy as it can be and still be usable at fifteen feet. My AT&T oordless phone, on the other hand, probably can go twenty-five feet or more (but not very much more). However, I don't accept output power limitation by the FCC as a legitimate excuse. We pick up little tiny signals from satellites that are thousands of miles away. Ham radio operators pick up -- when the ionosphere or somebody up there provides a cooperative bounce -- low level signals from around the world. The FCC probably doesn't prescribe a particular sort of modulation or the use of the cheapest chip available. If a 0.6 watt handheld portable cellular phone can talk to a cell site miles away, which it can, with clear reception both ways, certainly someone could design a cordless phone that really lives up to the traditional 1,000 foot claim. If anyone knows of one, please let me know! I'd like to buy a couple. Irving Wolfe Happy Man Corp. irv@happym.wa.com 206/463-9399 ext.101 4410 SW Point Robinson Road, Vashon Island, WA 98070-7399 fax ext.116
Shawn Nunley <shawn@ka> (08/23/90)
In article <11102@accuvax.nwu.edu> irv@happym.wa.com (Irving Wolfe) writes: X-Telecom-Digest: Volume 10, Issue 583, Message 5 of 11 >In <11015@accuvax.nwu.edu> john@bovine.ati.com (John Higdon) writes: >>BTW, 25-30 feet is about all you can expect from a cordless phone in >>an electrically hostile environment, such as the one I have here. >He doesn't know how lucky he is, or how bad Panasonic cordless phones >can be despite the quality of their other phone equipment. Mine >starts becoming a little noisy at five feet and is about as noisy as >it can be and still be usable at fifteen feet. My AT&T oordless >phone, on the other hand, probably can go twenty-five feet or more >(but not very much more). I suspect that either the quality of cordless phones is on the rise, or that these folks have purchased defective phones. I purchased a Sony, tne channel cordless that performs very well in an electrically hostile environment. By very well, I mean that I can have a mostly noise-free conversation as far away as three houses down and across the street! That is well over 300 feet from the base station. In addition, the Sony has a stand-by battery life of seven days, twelve hours of continuous talking. When I am using my computer (a large beast of power cosumption), I notice no degredation in quality whatsoever. In fact, nothing in my house seems to affect the quality of sound at all. Internet: shawn@ka.novell.com UUCP: {ames,sun,apple,mtxinu,cae780,sco} !novell!shawn Shawn Nunley Tel: (408) 473-8630
Jim Gottlieb <jimmy@icjapan.info.com> (08/23/90)
In article <11102@accuvax.nwu.edu> irv@happym.wa.com (Irving Wolfe) writes: >He doesn't know how lucky he is, or how bad Panasonic cordless phones >can be despite the quality of their other phone equipment. Mine >starts becoming a little noisy at five feet and is about as noisy as >it can be and still be usable at fifteen feet. My AT&T oordless >phone, on the other hand, probably can go twenty-five feet or more >(but not very much more). This is on cordless phones rated to be usable up to 300 meters. Here in Japan, the maximum allowed is 100 meters. Some of the ones sold here are rated at a maximum of ten meters. Now if it really goes ten meters this shouldn't be a problem since most Japanese apartments are not more than ten meters wide or long (think of them as a walk-in closet). But my sister tells me that her 300 meter cordless phone (in New York) fades out if she crosses to her husband's side of the bed. I wonder if you actually have to sit on top of the base unit on these ten meter models? I'll find out soon. I'm supposed to hook up a jack for one in the next few days. Note that because Japanese living quarters are so small, the local market is full of space-saving devices. The big rage right now is combination telephone/cordless-phone/answering-machine units. I just saw an ad for one that adds a fax to the above.
johns@scroff.uk.sun.com (John Slater) (08/25/90)
In article <11206@accuvax.nwu.edu>, shawn@ka (Shawn Nunley) writes: >the Sony has a stand-by battery life of seven days, twelve >hours of continuous talking. ... and the hernia is getting better by the day. I'm saving up to buy the optional Batt-Kart(TM) accessory, which enables me to drag the battery unit around on wheels rather than lift it. Is this the world's first "transportable" cordless phone ? :-) Seriously, if it can do that then it's an impressive beastie. My SouthWestern Bell model does 24 hours/1 hour, I think. John Slater Sun Microsystems UK, Gatwick Office
shawn@ka (Shawn Nunley) (08/27/90)
I wrote: >>the Sony has a stand-by battery life of seven days, twelve >>hours of continuous talking. And John Slater wrote: > ... and the hernia is getting better by the day. I'm saving up to buy >the optional Batt-Kart(TM) accessory, which enables me to drag the >battery unit around on wheels rather than lift it. >Seriously, if it can do that then it's an impressive beastie. My >SouthWestern Bell model does 24 hours/1 hour, I think. I kid you not! Since I am at home now, I can add the model number... 8) It is a Sony SPP-120. The nicest thing about it is that it never has to sit in a base. It comes with two batteries. One charges while the other is in the phone. The battery life is as claimed, amazingly enough. I am very impressed with the unit. Whats even *MORE* amazing is that the battery is smaller *AND* lighter that a regular nine-volt. The wonders of modern technology... Internet: shawn@ka.novell.com UUCP: {ames,sun,apple,mtxinu,cae780,sco} !novell!shawn Shawn Nunley Tel: (408) 473-8630