mobo@sphinx.uchicago.edu (Samuel Wilson) (08/14/87)
I realize that there is almost never anything truely new (plus ca
change, plus c'est la meme chose) in the PC world, but here is
something that is new to me:
My father has an Epson Equity II, and in it has an Everex
Evercomm 1200 baud 1/2 card modem. Works fine. My brother, who
also has an EEII, borrows the thing, plugs it into his machine,
turns it on and gets . . (dramatic pause) . . Jack Buck and the
St.Louis Cardinals loud and clear on the 1" speaker. KMOX, the
voice of the Radio Cardinals.
I have questioned him closely and he had not been drinking
heavily, had not been near halucinogenic drugs for weeks, and had
not had any recent dental work.
If anyone has had any experience with this (or knows how to cure
it) please let me know. In the unlikely event that this is a
common occurrence, I'll summarize to the net.
Sam Wilson ... ihnp4!gargolye!sphinx!mobo
mobo@sphinx.uchicago.edu
MCI: SWILSONgeorge@genat.UUCP (George Gorsline) (08/14/87)
Pick-up of radio signals by non-receiving equipment is not that unusual.
Manufacturers routinely don't put in any "extra" components which would
prevent "RFI - radio frequency interference" because the odds are that the
equipment won't be close enough to the radio signal source for the design
shortcut to be noticed. This is a well and painfully known occurance to hams,
as most of us have had to remedy neighbour's electronic phones, stereos, etc.
to eliminate this. What happens is that the serial cable or sometimes the
power cord acts like an antenna and feeds the signal into the computer/modem
where among all of the circuit components, a crystal set can easily be found.
This is not multi-tasking, rather its digital/analogue co-processing! :-).
Standard remedies include using shielded cables, shorter cables, and/or use of
a toriodal choke through which the cable in question is wrapped around. Of
course, the computer and modem should be plugged into a good three-wire
grounded AC outlet. Chances are you already know a ham as a neighbour or at
work. He/she should be able to help and glad its KMOX and not their own
set-up who is your unintended guest. If not, post a request for help to
rec.ham-radio.
--
George Gorsline, Jr. VE3FIU / K8HI
One of the VE3YDX gang... Y DX? Because it's there(~Y)!
__... ...__ . ... _.. _.._
Genamation, 351 Steelcase Rd. West, Markham Ontario L3R 3W1
{allegra|linus|ihnp4|...}!utzoo!mnetor!genat!george
(416) 475-9434jack@csccat.UUCP (08/18/87)
In article <2187@sphinx.uchicago.edu>, mobo@sphinx.uchicago.edu (Samuel Wilson) writes: > > Evercomm 1200 baud 1/2 card modem. Works fine. My brother, who > also has an EEII, borrows the thing, plugs it into his machine, > turns it on and gets . . (dramatic pause) . . Jack Buck and the > St.Louis Cardinals loud and clear on the 1" speaker. KMOX, the > voice of the Radio Cardinals. > If anyone has had any experience with this (or knows how to cure > it) please let me know. > Sam Wilson ... ihnp4!gargolye!sphinx!mobo Figure out what the inductance of the speaker is and place a capacitor across the speaker terminals to create crude low pass filter. It's late and my mine is fuzzy but probably.. oh.. I am going to get flamed for this (it been a long time since I did RF stuff) but try a 0.01 or 0.1uF ceramic, your not worryed about sound quality here and I think problem has to do with the driver transistors base being floated and a simple detector curcuit has been created and I bet you brother lives within a close proximity to the transmitter or the transmitter is of very high power most major league baseball flagship stations are and AM no doubt. (if it's FM, cute!) -- See above (214)661-8960
jeffb@mcnc.UUCP (Jeffrey B. Butterworth) (08/24/87)
I've had the same problem with my modem. I waited for six weeks for my dream come true, a 2400 baud Mitac modem. As soon as I got it, I ripped it out of the box, hooked it up, turned it on, and found out how to make mock apple pie from a local radio show. After some experimentation, I found that I could get the normal modem noises to take over the speaker by turning up the volume. Now the beeping of the modem can wake the dead. Another way of shutting off the country music and talk shows was to turn the volume way down. Unfortunately, turning the volume down that far causes the speaker to be silent altogether. I discovered that the radio only plays when the modem is hooked into the phone outlet. Of course, that helps me very little, since my modem is one of the old fashioned kind that has to be hooked into the telephone network. This discovery does suggest though, that the telephone wiring is acting as an antenna. I'm not sure if I have sub-standard wiring. It could also be caused by the presence of a rather powerful AM radio station in the same part of town. If there are any more possessed modem stories out there, please tell me. I'd love to be able to here my modem dialing without disturbing the neighbors two blocks away. Thanks, Jeff Butterworth Raleigh, NC Microelectronics Center of North Carolina
rap@oliveb.UUCP (Robert A. Pease) (08/25/87)
In article <2489@alvin.mcnc.UUCP> jeffb@alvin.UUCP (Jeffrey B. Butterworth) writes: >I discovered that the radio only plays when the modem is hooked into the phone >outlet. Of course, that helps me very little, since my modem is one of the old >fashioned kind that has to be hooked into the telephone network. This >discovery does suggest though, that the telephone wiring is acting as an >antenna. I'm not sure if I have sub-standard wiring. It could also be caused >by the presence of a rather powerful AM radio station in the same part of town. > > Thanks, > Jeff Butterworth > North Carolina Be advised. If you have trouble with radio signals in your phone wireing you can call the service center for your phone company and they will install an RFC (Radio Frequency Choke) in your line which will block the radio signal before it gets into your home. This is a known and common problem with homes near a radio transmitter and is not limited to AM broadcast band radio (ie. if the ham radio operator causes you trouble the phone company will help with that too). Call them and ask. It couldn't hurt. -- Robert A. Pease {hplabs|fortune|idi|ihnp4|tolerant|allegra|glacier|olhqma}!oliveb!olivej!rap
merchant@dartvax.UUCP (Peter Merchant) (08/25/87)
In article <2187@sphinx.uchicago.edu>, Samuel Wilson writes: > My father has an Epson Equity II, and in it has an Everex > Evercomm 1200 baud 1/2 card modem. Works fine. My brother, who > also has an EEII, borrows the thing, plugs it into his machine, > turns it on and gets . . (dramatic pause) . . Jack Buck and the > St.Louis Cardinals loud and clear on the 1" speaker. KMOX, the > voice of the Radio Cardinals. > Sam Wilson ... ihnp4!gargolye!sphinx!mobo A friend of mine had a similar problem with a telephone. She lived right across the street from a local AM Radio Station and, occasionally, the radio signals would be picked up by the telephone wires. Sometimes it was pretty loud and you could barely hear the person at the other end. If your brother lives around KMOX's transmitters, that could be it. Of course, you can write a program to draw a radio on the screen and impress your friends with your programming talent... :^D -- "Take your passion Peter Merchant (merchant@dartvax.UUCP) And make it happen."
spm@edison.UUCP (08/26/87)
In article <2489@alvin.mcnc.UUCP>, jeffb@mcnc.UUCP (Jeffrey B. Butterworth) writes: > I've had the same problem with my modem. I waited for six weeks for my dream > come true, a 2400 baud Mitac modem. As soon as I got it, I ripped it out of the > box, hooked it up, turned it on, and found out how to make mock apple pie from a > local radio show. > > If there are any more possessed modem stories out there, please tell me. I'd > love to be able to here my modem dialing without disturbing the neighbors two > blocks away. You might be able to *fix* the problem by plugging a *real* phone into the back of the modem. The inductance of a real ringer may be just right to shunt away the RF signal. -- Steve Monett GE Fanuc Automation - Charlottesville, VA spm@edison.GE.COM old arpa: spm%edison.GE.COM@seismo.CSS.GOV spm@edison.UUCP old uucp: {seismo,decuac,houxm,calma,hpfcla}!edison!spm
mobo@sphinx.uchicago.edu (Samuel Wilson) (08/27/87)
I've had about 15 responses to the original posting about the internal
Everex Evercom modem that plays the radio when the computer is turned
on. Recommendations have been (1) that I isolate the modem using some
sort of metal shield; (2) turn the computer a few degrees so that the
modem/ receiver doesn't get good reception; (3) get the phone company
to put on a RFC (radio frequency choke, thanks Robert Pease) (4) move
away from where I live, assuming that I am too close to the
transmitter (the modem is a long way (30 miles) from the tower, but no
thanks anyway); (5), that I wire in some sort of filter in front of
the speaker (beyond my technical competence); (6) that I trade in the
$119 special for one that has RF screening (probably the best bet),
and (7) my favorite, that I disconnect the telephone line when I want
to use the modem, because it is acting as an antenna...
More detail is available on the above options, if anyone is interested.
Thanks to everyone who responded.
Samuel Wilson ..ihnp4!gargoyle!sphinx!mobo
FOTMOBO@UCHMVS1.Bitnet
University of Chicago, Division of Social Sciences