home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
QRZ! Ham Radio 4
/
QRZ Ham Radio Callsign Database - Volume 4.iso
/
files
/
arrl
/
tis
/
fcctele.txt
< prev
next >
Wrap
Text File
|
1994-11-27
|
25KB
|
515 lines
Transcribed from printed pages by the Field Services Department of the
American Radio Relay League, Inc., 225 Main St., Newington, CT 06111,
(203) 666-1541.
Subject: TELEPHONE INTERFERENCE SURVEY
February 28, 1994
Telephone Interference Survey
Background
The Federal Communications Commission (FCC) receives 25,000
complaints per year from individuals who are unable to use their
telephones because nearby radio stations interfere with the proper
operation of the telephones. Whenever the radio stations are on
the air, the telephones pick up their transmissions which then
override any ongoing telephone conversation.
The FCC's Field Operations Bureau (FOB) has done an informal
survey to obtain information about telephone interference such as:
- which telephones are affected
- what type transmitting stations are involved
- the power levels at which the stations were transmitting
- whether commonly available filters would be effective in
eliminating the interference
- whether specially designed telephones would be effective in
eliminating the interference
In setting forth the results of its informal survey, FOB
emphasizes that, because this survey is based on a random sample
it cannot be claimed that identical results would be derived under
scientific surveying and testing, nor should the results be
construed as FCC endorsement or criticism of any particular
manufacturer's product. Rather, FOB believes these results to be
a good "first look" at the problem.
Procedure
Thirty-five FCC field offices across the country participated in
the survey. Each office was to choose three recent complaints of
telephone interference on a random basis, and then to investigate
the complaints.
At the transmitting station FOB staff would determine the type of
station (i.e., amateur, citizens band, broadcast, etc.), measure
the station power, and obtain information on antenna height,
antenna gain, and distance from the complainant.
At the complainant's location, FOB would disconnect all
telephones, take them to a chosen telephone jack, and plug them in
one at a time while the station was transmitting. FOB would then
record which telephones received interference and which did not.
FOB also tested the effectiveness of several commercially-
available telephone filters, connecting the filters to telephones
which were receiving interference while the radio station was
transmitting.
Finally, FOB connected "bulletproof" telephones to the telephone
jacks and observed whether these telephones received interference.
A "bulletproof" telephone is one that is specially designed to be
immune to interference.
Findings
Types of Transmitting Stations
FOB inspected 108 transmitting stations which were involved in the
telephone interference complaints, as follows:
Citizens Band 47
Amateur 27
AM Broadcast 23
FM Broadcast 10
International Broadcast 1
Power Levels
The power levels of the radio transmitting stations varied from
two watts to half a million watts. One-third of the transmitting
stations operated with less than ten watts, and one-third of the
interfering stations were broadcast stations using between 3000
and half a million watts. Attachment 1 lists the power levels of
the transmitting stations.
Types of Telephones
FOB tested 241 telephones found in the complainants' residences
for interference. Of the 241 telephones 68 percent received
interference. Attachment 2 lists the telephones tested. FOB did
not observe interference on 32 percent of the telephones it
tested. These telephones are listed in Attachment 3.
Types of Filters
FOB tested the effectiveness of the AT&T Z100B1 filter on 138
telephones receiving interference. After connecting the filter to
the telephones, 62 percent of the telephones continued to receive
interference. The filter did eliminate interference on 38 percent
of the telephones. A number of other filters were also tested on
82 telephones receiving interference. As a group these filters
eliminated interference on 29 percent of the telephones. They did
not eliminate interference on 71 percent of the telephones.
Attachment 4 lists the filters which eliminated the interference.
Bulletproof Telephones
The FCC tested "bulletproof" telephones at 52 locations where the
individuals were receiving interference to their telephones. The
"bulletproof" telephones eliminated interference at 96 percent of
the locations.
Conclusions
The transmitting stations most likely to cause telephone
interference are citizens band, amateur, and broadcast stations.
Citizens band stations accounted for half the telephone
interference cases. Amateur stations and broadcast stations
accounted for the other half.
The power levels used by the radio transmitting station did not
appear to be a significant factor in causing telephone
interference. Power levels of 10 watts or less caused telephone
interference in a third of the cases.
A large portion of the residential telephones appeared to be
susceptible to interference from nearby radio transmitting
stations. Although some telephones did not receive interference,
the limited nature of the testing performed in conjunction with
this survey would not support the conclusion that they would
always reject interference.
Telephone interference filters cannot be relied upon to eliminate
telephone interference: in two out of three cases in the test
sample, they did not work. Manufacturers can design telephones to
be interference free. "Bulletproof" telephones were immune from
interference virtually all of the time.
A Final Note
Notwithstanding the 25,000 reports of telephone interference the
FCC has received to date, it is FOB's experience that, as large as
this number is, it probably represents only a fraction of the
actual instances in which this interference occurs. Given the
enormous numbers of instances in which this type of interference
is experienced by consumers, it is our hope that this survey,
notwithstanding its informality, will serve as a catalyst for
affected parties to productively address and resolve this problem.
As always, FOB remains ready to assist in that effort.
ATTACHMENT 1
FIELD OPERATIONS BUREAU
TELEPHONE INTERFERENCE SURVEY
POWER LEVELS OF INTERFERENCE SOURCES
UNKNOWN 2 sources
2 watts 4 sources
3 watts 7 sources
4 watts 14 sources
5 watts 7 sources
6 watts 1 source
7 watts 4 sources
12 watts 2 sources
26 watts 1 source
30 watts 1 source
35 watts 1 source
50 watts 1 source
53 watts 1 source
54 watts 1 source
57 watts 1 source
75 watts 1 source
80 watts 1 source
100 watts 5 sources
101 watts 1 source
110 watts 2 sources
114 watts 1 source
131 watts 1 source
150 watts 1 source
160 watts 1 source
200 watts 1 source
250 watts 1 source
438 watts 1 source
462 watts 1 source
500 watts 3 sources
600 watts 1 source
800 watts 1 source
1,000 watts 3 sources
1,500 watts 2 sources
3,000 watts 2 sources
5,000 watts 5 sources
8,000 watts 1 source
10,000 watts 4 sources
16,000 watts 1 source
25,000 watts 1 source
50,000 watts 11 sources
51,000 watts 4 sources
54,000 watts 1 source
100,000 watts 1 source
500,000 watts 1 source
Total sources: 108
ATTACHMENT 2
FIELD OPERATIONS BUREAU
TELEPHONE INTERFERENCE SURVEY
TELEPHONES RECEIVING INTERFERENCE
fo fil ix power att oth fcc make model
DL N AMA 800 N N Y (UNKNOWN) (UNKNOWN)
AL N CB 4 N N Y (UNKNOWN) (UNKNOWN)
PL N CB 2 N N Y AT&T (NONE)
DT N CB 5 N N Y AT&T (NONE) (FCC AS593M-70230)
LR N AM 1000 Y AT&T 100
KI N FM 3000 N AT&T 1306
KI N AMA 100 N AT&T 1504
DV N AM 5000 Y Y Y AT&T 150E
NY N CB 3 Y Y AT&T 1510
PO N AMA 35 Y N AT&T 1521
BS N AM 10000 Y N AT&T 1532
GI N AMA 53 N N AT&T 1611
DL Y CB 5 N Y AT&T 1618
KI N AMA 100 N AT&T 210
KI N AMA 100 N AT&T 210
DS N AM 5000 Y AT&T 210
DS Y AMA 500 N Y AT&T 210
NF Y CB 3 Y N Y AT&T 210
PL N AMA 1000 Y Y Y AT&T 530
DL N AMA 800 Y Y Y AT&T 5455
GI N AMA 101 N AT&T 610
BF N AMA 100 N Y AT&T 710
KI N CB 5 N AT&T 720
CG N AMA 1000 Y Y AT&T 720
KC Y CB 4 N Y AT&T 725
GI N AMA 101 N AT&T 725
PA N CB 3 N Y AT&T 732
HL N AMA 462 N N AT&T 732
MA Y AMA 600 N AT&T AOM9RN 10451-TE-E
LR Y CB 4 N AT&T AS 550Z 71597
MA N AMA 50 N AT&T ASSS0Z-71597-TE-E
DT N AM 438 N AT&T MODEL 1506
NY N AM 25000 N N AT&T PRINCESS
BM N CB 7 N N Y AT&T PRINCESS AS 550 Z-71322
PA N CB 3 N Y AT&T SPKK REMOTE & ANS MACHINE
PO N AM 50000 Y Y AT&T SW204
BM N FM 16000 Y N Y AT&T TRIMLINE 210
BF Y AM 50000 N Y AT&T TRIMLINE 210
DL N CB 5 Y Y AT&T TRIMLINE 220
NF N AMA 1500 Y Y Y AT&T TRIMLINE AS550Z-71597-T
ST N AM 10000 Y N Y AUDIOVOX AT-11
PO N AM 50000 Y N BELL FAVORITE
PL N AM 5000 Y BELL TT-51490
KI N CB 5 N BELL PHONES 100-5800
AT Y CB 160 N N Y BELL SOUTH 2000
BS N AM 50000 Y N BELL SOUTH 227V
DT N CB 3 BELL SOUTH 473
KI N CB 5 N BELL SOUTH 473
DS N AM 5000 Y BELL SOUTH 473
MA N AMA 600 BELL SOUTH CWIMLA-61669-ANN
OR N AMA 100 N Y BELL SOUTH DPK-62W70687-TE-T
AT N IB 500000 N Y BELL SOUTH HAC 572
PS Y AMA 150 N N Y BELL SOUTH TP-201 L-10
SF N AM 50000 Y CANON FAX-350
PO Y AMA 500 Y CODE-A-PHONE 1610
LA Y AM 50000 N N COMDIAL 25270-IY
SF N AM 50000 COMDIAL VOICE EXPRESS
ST N CB 75 N N Y CONAIR PR 1000
AT Y CB Y Y CONAIR PR 5001
LV N CB 57 N N CONAIR SW 2502
TP N CB 5 CONAIR SW204
BE N AMA 80 N CONAIR SW204A
PO N AM 50000 Y CONAIR TR101
AN N FM 51000 Y Y CONAIRPHONE PR1006
PO Y AMA 500 Y CONAIRPHONE PRIMA SERIES
DT N CB 3 N N Y CONAIRPHONE SW-102
HL N AM 10000 DELTA HEK-EB-200DSIHF-EXT
SD N CB 12 N FORTEL CORP RECORD A CALL #2140
SF N CB 2 N N GENERAL ELECTRIC 12-MEMORY 2-9240A
PO N AM 50000 Y N GENERAL ELECTRIC 2-9051LRA
MA N CB 6 N GENERAL ELECTRIC 2-9166B
CG N AM 50000 Y Y GENERAL ELECTRIC 2-9166B
TP Y CB 4 N Y GENERAL ELECTRIC 2-9167A
KC N CB 2 Y Y GENERAL ELECTRIC 2-9212BLB
LV Y CB 4 N N GENERAL ELECTRIC 2-9243
DT N AM 438 GENERAL ELECTRIC 2-9243C
KC N FM 8000 N GENERAL ELECTRIC 2-9355A
LV Y CB 5 N N GENERAL ELECTRIC 2-9356
VB N AMA 100 Y GENERAL ELECTRIC 2-9400C
HL N FM 54000 GENERAL ELECTRIC 2-94050A
HL N FM 54000 GENERAL ELECTRIC 2-94050A
HL N FM 54000 GENERAL ELECTRIC 2-94050A
HL N FM 54000 GENERAL ELECTRIC 2-94050A
MA N CB 6 N GENERAL ELECTRIC 2-9420A
HU N FM 100000 N GENERAL ELECTRIC 2-9675A
PS Y CB 5 Y Y Y GENERAL ELECTRIC 2-9892A
DV N CB 2 Y Y Y GENERAL ELECTRIC 2-9895A
LV N CB 4 N N GENERAL ELECTRIC 29270 A
DV N AM 5000 Y GENERAL ELECTRIC 7-4700A
LA N AM 5000 Y Y GENERAL ELECTRIC CRYSTAL CLEAR PLUS
BF N CB 5 N Y GENERAL ELECTRIC MEMORY MODEL 21
MA N CB 6 Y GENERAL ELECTRIC NO 29420A
SD N CB 54 N N GENERAL ELECTRIC SPEAKER PHONE 2-9375F
CG N AMA 1500 GENERAL ELECTRIC TL-5/TPS
PO N AMA 35 Y N GTE 58821
ST Y FM 51000 N N Y GTE 7400
GI N AMA 101 Y GTE AUTO ELEC - WALL PHONE
GI N AMA 101 Y GTE AUTOMATIC ELECTRIC
PL N AM 5000 N IMA (NONE)
AL Y AM 5000 N N Y ITT (CORINTH 3480 FEATURE TELEPHONE
TELECOM. CORP)
DS N FM 3000 Y N Y LENOX SOUND P4316
PL N AM 5000 LLOYDS (PHONE- T510
CLOCK-RADIO)
HU N CB 110 N LONE STAR 912
PA N CB 4 Y LONE STAR TRIMLINE
BS N CB 5 N N LOTEL 5020 DUEL LINE
BS N CB 5 N N LOTEL 5020 DUEL LINE
FE N AMA 131 N NORTHERN TELECOM FCC REG #AB6982-68817-TE-T
AN N FM 51000 Y Y NORTHERN TELECOM NT3L00AA
DT Y CB 5 Y N Y NORTHERN TELECOM SYMPHONY 3000
PS N AMA 200 N N Y NORTHWESTERN BELL "EASY TOUCH"
SD Y CB 12 N NORTHWESTERN BELL BASIC TGT 51450
LV N CB 4 N N PAC BELL TR 2203 CHAC
PO Y AM 50000 N N PACTEL FE5700
DS N AMA 500 N Y PANASONIC EASA-PHONE VA-8205
NY N AMA 100 Y Y PANASONIC EASA-PHONE-AUTO LOGIC
BS N AM 10000 N N PANASONIC EASE PHONE KX-TX175-B
TP Y CB 3 N N Y PANASONIC KX-T-2420
SF Y AMA 250 Y N PANASONIC KX-T-3155
DV N AMA 114 N Y Y PANASONIC KX-T2315
DL N CB 4 Y Y Y PANASONIC KX-T2315
PO Y AM 50000 Y Y PANASONIC KX-T2355
CG N AMA 1500 N Y PANASONIC KX-T2355
ST Y AM 10000 N N Y PANASONIC KX-T2622 EASAPHONE
HL N AMA 462 PANASONIC KX-T3145
OR N AM 50000 N Y PANASONIC KXT 2388
KI N CB 5 N PHONEMATE 3900
NF N CB 7 Y N Y PHONEMATE 3950
GI Y AMA 101 N PHONEMATE 4650
BS N AM 10000 N N RADIO SHACK 209 DUCPHONE 43-617A
DS N FM 3000 Y RADIO SHACK 43-384
PS Y CB 5 RADIO SHACK 43-384
DT N CB 3 Y RADIO SHACK 43-625 DUOFONE 202
TP Y CB 4 N Y RADIO SHACK 43.430
PO Y AM 50000 Y N RADIO SHACK DUOPHONE TAD-250
OR N CB 4 Y RADIO SHACK ET 200
LR N CB N SANYO TA S 855
AT N CB 160 N Y SEARS 3293 4761550 SR 3000
KI N FM 3000 N SEARS 34403
DL N AMA 800 Y Y Y SEARS 34505
LV N CB 4 N N SEARS SR-2000
KI N FM 3000 N SOUND DESIGN 7255 AR
TP Y CB 3 N N Y SOUNDESIGN 7339 IVY
NY Y AMA 100 Y Y SOUTHWESTERN BELL FCC 2555
BE N CB 4 N SOUTHWESTERN BELL FREEDOM PHONE
ST Y CB 75 N N Y SOUTHWESTERN BELL FREEDOM PHONE FC 2570
BS N AM 10000 Y N SOUTHWESTERN BELL FT-325
SF N AM 50000 STROMBERG IMAGE 1 AND IMAGE 2 DTMF
ST Y FM 51000 N N Y TECHNICO TT-2201
SJ N CB 26 N Y TELEFONICA TXE-1
HISPANO AMERICAN
SJ N CB 7 N Y TELEFONICA TXE-1
HISPANO AMERICAN
TP N CB 3 N N Y TELKO 221
ST Y CB 4 N N Y THOMAS PP9D NOSTALGIA PHONE
FE N AM 50000 Y TIME LIFE (MADE (NONE)
IN TAIWAN)
DS N AM 5000 Y Y Y TISONIC PT-91
LV Y CB 5 N N ULTRSONIC 019
KC N FM 8000 N UNIDEN TRIMLINE
FE N AM 50000 Y UNISONIC (NONE)
AL Y AM 5000 N N N UNISONIC (NONE)
VB Y CB 30 Y UNISONIC 6434
BM N CB 4 N N Y UNISONIC 9370
PL Y AM 5000 Y Y Y WESTERN ELECTRIC (NONE)
DT N AM 438 Y Y WESTERN ELECTRIC (NONE) ROTARY DIAL PHONE
DT N AM 438 WESTERN ELECTRIC (NONE) ROTARY DIAL PHONE
NF N AMA 1500 Y Y Y WESTERN ELECTRIC AS543M-62587-TE-T
PA N AMA 110 N Y WESTERN ELECTRIC CS 2500 DMG 84121
fo=Field Office,fil=filter already installed? ix=Service causing
interference power=power of transmiter att=Problem corrected with
AT&T Z100-B1? oth=Problem corrected with other filter?
fcc=Problem corrected with FCC "bullet-proof" phone?
ATTACHMENT 3
FIELD OPERATIONS BUREAU
TELEPHONE INTERFERENCE SURVEY
TELEPHONES NOT RECEIVING INTERFERENCE
off filter make model
NF Y AT&T 1316C
DL N AT&T 1321
SF N AT&T 1323
NY N AT&T 5200
SF N AT&T 5200
BF N AT&T 5400
ST N AT&T 5600
PA N AT&T 60921
CG N AT&T 700
ST N AT&T 730
PA N AT&T ANS MACHINE
PA N AT&T AS5 THA-60921-MT-E
DL N AT&T CS8702A
DL Y AT&T NE-229A
OR N AT&T OLD DIAL STYLE
BF Y AT&T TRIMLINE
BM N BELL SOUTH 665 CORDLESS PHONE
HU N BELL SOUTH HAE-701
OR N BELL SYSTEM TRIMLINE
AL N COBRA AN-8519
DT N COBRA ST-410
SD N CODE A PHONE 8100
AL N CONAIR CORP XS2400
LV N CONAIR CORPORATE AMERICA
BS N DAK INDUSTRIES DAL-4000 AX
NF Y DAK INDUSTRIES DK 4000 AX
CG N GANDALF COMDIAL
AL N GENERAL ELECTRIC 2-9051LRB
KC N GENERAL ELECTRIC 2-9800B
BM N GTE (UNKNOWN)
ST N GTE 980 SLIMLINE
PS N ITT 183499-236
FE N ITT 500D
AN N ITT RJ11C
AL N LENNOX SOUND PH-319
HL N UNKNOWN (CHINA) FCC #: GEZ 364-16521 TE-E
HL N NORTHERN TELECOM SYMPHONY 1000
DV N NW BELL FAVORITE PLUS DHT6CJ-14584-TE
BS N PANASONIC EASE PHONE-ONE LINE
HU N PANASONIC GASA-PHONE
DV N PANASONIC KX-T-3120
HL N PANASONIC KXT-2355
KC N PHONEMATE 4300
ST N RADIO SHACK 43-368A
FE N RADIO SHACK 43-500
FE N RADIO SHACK 43-5018
DV N RADIO SHACK 43-621
OR N SEARS 329 34451750
DT N SEARS 34413
GI N SEARS HAC 3466
ST N SEARS SR 3000 SERIES
SF N SHARP UX-172
SF N SOUND DESIGN AM/FM CLOCK RADIO PHONE
AL N SPECTRA PHONE TL-4
DT N STC TELECORP INC SOUNDDESIGN 7255
ST N TELECONCEPTS (NONE)
NF N WESTERN ELECTRIC (UNKNOWN)
BM N WESTERN ELECTRIC (UNKNOWN)
DL N WESTERN ELECTRIC (UNKNOWN)
KC Y WESTERN ELECTRIC (UNKNOWN)
LA N WESTERN ELECTRIC "LA OLYMPIC PHONE"
PA N WESTERN ELECTRIC 2554 BMPG-82103
BS N WESTERN ELECTRIC RB 1311 (ROTARY)
NF Y WESTERN ELECTRIC TRIMLINE #CS 2224A
NF N WESTERN ELECTRIC TRIMLINE PHONE
ATTACHMENT 4
FIELD OPERATIONS BUREAU
TELEPHONE INTERFERENCE SURVEY
OTHER FILTERS TESTED
K-COM RF-1 1
K COM RF1 3
RADIO SHACK-SNAPON 1
TCE 1
TCE536 2
TCE TP12 4
TEC RF1400 2
TII 931-W1 2
The filters listed here deserve further study. During the
project, FOB found that these filters eliminated interference when
tried in individual cases. However, because FOB did not use any
of these filters in a sufficient number of cases, we cannot
conclude whether any of them would be effective in eliminating
interference most of the time.
ATTACHMENT 5
FCC BULLET PROOF PHONE
Manufacturer Make Address
Pro Distributors Western Electric 2811 74th Street,
Desk Model Lubbock, TX
Touch Tone 1-800 (658-2027)
TCE Labs Rural Route 9
Box 243D
New Branufels, TX
78133
(800-KILL-TVI)
Note: All phones were refurbished, internally modified commercial units.