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Additional information on this subject and related topics can be found in back issues of QST and the following:
The ARRL has an extensive catalog of books and materials related to Amateur Radio.
GENERAL INFORMATION ON RADIO FREQUENCY INTERFERENCE
Interference Primer - Parts 1 and 2 Derived from QST February and March 1992 Lab Notes columns. Copyright © 1992 by the American Radio Relay League, Inc. All rights reserved.
Prepared as a membership service by the American Radio Relay League, Inc., Technical Information Service.
The ARRL RFI Book, American Radio Relay League, 225 Main St., Newington CT 06111, (860) 594-0200.
AC Power Interference Handbook, By Marv Loftness, KB7KK
The Radio Amateur's Guide to EMC, Radio Society of Great Britain, 3 Abbey Court, Fraser Road, Priory Business Park, Bedford MK44 3WH Great Britain
Ordering information for the above three books and more can be found on the ARRL Web page at: http://www.arrl.org/catalog/interference-df.phtml
The ARRL Technical Information Service (TIS) has prepared a series of additional EMI web pages. The "EMI/RFI Page" (this page) provides a menu for more comprehensive pages related to RFI, such as "EMI/RFI - Telephone." For an electronic copy of the entire TIS web page list, see http://www.arrl.org/tis/.
Contact the ARRL "RFI Desk" for additional information and help with interference problems involving Amateur Radio stations (email rfi@arrl.org).
For interference involving other radio services contact the FCC Consumer and Governmental Affairs Bureau (FCC CGB), 1270 Fairfield Road, Gettysburg, PA 17325, National Call Center phone: 888-CALL-FCC, email fccinfo@fcc.gov, web: www.fcc.gov/cgb
An extensive list of free pamphlets about electromagnetic interference and lightning protection is available from Industrial Communications Engineers. Request their free publications list.
Barker and Williamson Model FL10/1500
Bencher Model YA-1
Bird Electronics Corporation Model 5040 series
Industrial Communications Eng Model 400 series band-pass, Model 420 series low-pass
MFJ Enterprises Model MFJ-704
Ten-Tec Model 5061
Unadilla Antenna Model WA2ZOT, WA2ZOT-6 Meter
The high-pass filter is the first line of defense against TVI to antenna-connected televisions that is caused by HF radio transmitters! A high-pass filter is not usually needed or effective with interference problems to CATV-connected TVs. For cable interference problems, use a common-mode choke. Note: High-pass filters are usually available from the local electronics distributor that sells parts to your local electronics service businesses. Consult the Yellow Pages under "Electronic components - wholesale and manufacturer."
Channel Master several models
Industrial Communications Engineers Model 430 series high-pass
Radio Shack 15-579 75-ohm, 15-582 or 15-581 300-ohm
Ten-Tec Model 5060
Winegard Model HP-2700
A 50 MHz High Pass TVI Filter you can build from the United Kingdom Six Metre Group (UKSMG).
The Yankee Clipper Contest Club has an article on common mode chokes by Chuck Counselman, W1HIS.
Alternate formats: PDF MS Word.
Industrial Communications Engineers
Starplex, Inc Model Ghost Buster dual-ferrite choke
The following set-top converters have been reported as being relatively immune to cable-TV interference: (Additional reports are sought.)
General Instruments/Jerrold: Bar code - TOA1104176B5
Amateur VHF stations can interfere with antenna-connected televisions. Television tuners do not often have much adjacent-channel rejection, resulting in severe fundamental overload. These tunable notch filters will reject the strong amateur signal, allowing the television to function normally. Note: these filters will not help when an amateur signal is interfering with cable channel 18 (channel E). In that case, the problem results because cable channel 18 and the Amateur 2-meter band occupy the same frequencies. Some of these filters are expensive. Contact the vendor before ordering.
Microwave Filter Company: 5KMT-A-I (reject 108-170 MHz) Filter: 5KV-E (Channel E (146.25 MHz) (Cable ch 18) trap) Filter: 5KV-K (Channel K (223.25 MHz) (Cable ch 24) trap) Filter: F6367-2 (Notch filter 50-108 MHz, 75-ohm) Filter: F6367-3 (Notch filter 108-216 MHz, 75-ohm) Filter: F6367-4 (Notch filter 216-450 MHz, 75-ohm) Filter: F6367-5 (Notch filter 450-900 MHz, 75-ohm) Note: They will sell single units.
US Electronics Filter: LLMBRLPF (pass ONLY VHF ch2-6 and 7-13) Filter: MBR-A-2-I (reject 88-170 MHz) Filter: MBR-A-I (reject 108-170 MHz) Filter: MWT-4 (pass 54-300 MHz, reject tunable notch) Note: Will sell single units. Call for nearest distributor.
Winegard Model: UT-2700 notched 470 to 800 MHz Model: BF-1700 attenuates 110-170 MHz (eliminates 2M signal)
K-Y Filter Company Model RF-1 and Model AM-1 for telephones.
Coilcraft Filter models RJ-11 (single line) and RJ-14 (2 line) - filters 150 kHz to 25 MHz.
Industrial Communications Engineers Model 460 series telephone/audio filters
Sparrevohn Engineering Model F-1 (single-line), Model F-2 (two-line)
OLD AT&T telephones, made by several different companies, notably models 300, 500 (rotary), 2500 (DTMF), 2554 (DTMF wall phone,). These phones are made by AT&T (Western Electric), Comdial (Stromberg Carlson), Northern Telecom, and ITT. These phones have no semiconductors in them and have a carbon microphone, hence the RF immunity. The only devices that can produce problems are the silicon carbide varistors. Most of these phones are no longer being manufactured but are sometimes found used at garage sales or flea markets.
The ARRL Technical Department has received one report (each) that the following telephones are immune to EMI. Additional reports about these telephones are sought. (Note - just because one phone by a particular manufacturer is immune does not indicate that ALL phones by that manufacturer are immune! Several of these manufacturers have phones for which we have received inteference reports.)
Phonemate 8250
AT&T 5300 and 5400 (cordless telephones.)
Conairephone PR1001
NT Meridian Centrex telephone sets
Understanding How Ferrites Prevent and Eliminate RF Interference to Audio Systems. Jim Brown, K9YC shares three years worth of practical engineering research on the use of ferrites to prevent RFI. Also of interest is Understanding and Eliminating RF Interference. Jim prepared this Power Point presentation for his local ham club. This discussion is focused on RFI to and from ham stations.
Common Mode Inductors for EMI Filters Require Careful Attention to Core Material Selection by Robert West, Magnetics, Division of Spang & Co.,
Fair-Rite Products Corp Note: Call to locate nearest distributor. Distributor Dexter Magnetic Materials has a number of locations around the US. Call 800-949-8950 to automatically connect to nearest Dexter office.
Radio Shack catalog #s 273-105 and 273-104
Industrial Communications Engineers Model 472 isolator, Model 400 series
Corcom provides RFI Line Filters as well as numerous other types of filters. They also carry a Variable-Frequency Drive (VFD) Line Filter, which may work on variable speed washing machines and similar appliances.
The W3NQN ac line filter by Array Solutions
Radio Shack Catalog: 15-1111 brute-force AC-line filter, 26-1395 surge- protection filter (it contains common-mode and differential mode AC-line filtering. Note: This model has been discontinued.)
Electronic Specialists, Inc. Carries a wide range of AC Power Line Protectors, industrial surge suppressors, ac power line voltage conditioners and regulators.
ETS-Lindgren offers a wide variety of power line filters and phone/signal/control filters plus related products.
Spectrum Control Inc. offers power line filters, EMI filters & filtered interconnects, and related products.
LCR Electronics offers power line filters, power entry filters and EMC filters.
HSC Electronics carries a wide variety of ac line filters.
Industrial Communications Eng Model 461 stereo , Model 440 mobile, Model 488 video
Radio Shack (mobile) 270-051, 270-055, 270-054, 270-012, 272-1085, 270-030
Winegard Model FT-7600 variable FM trap, Model VF-3000 VCR, Model VF-4000 VCR
The Technician's EMI Handbook, Clues and Solutions by Joseph J. Carr is published by Elsevier. You may obtain a copy from Purchase at Amazon or Purchase at Barnes and Noble. Also available is a Google Preview.
AC Electronics offers a fluorescent lighting ballast especially suitable in the presence of Power Line Carrier Signals (PLCS). This device provides additional filtering (and probably a higher impedance looking into the filter from the AC mains) over conventional ballasts.
The COMspkr is an RF interference resistant computer speaker system from West Mountain Radio.
RFI - Regulatory Information This web page contains information about Federal Communications Commission rules that apply to FCC preemption of local laws about RFI.
A summary of the FCC's study on telephone interference
FCC Policy for handling complaints of interference to home electronic equipment
ARRL Periodicals Index Search - This database contains the QST index from 1915 to the present and the QEX index from 1981 to the present. For QST issues from 1970 to the present, and some selected articles back to 1922 (when construction articles featuring tubes began in earnest), identifying keywords have been added to the technical articles. By entering keywords (ANTENNA) or combinations of keywords (CONSTRUCTION ANTENNA VERTICAL HF) into the Title words: field, you may create dynamic bibliographies.
Technical article KEYWORD list. Hints for more successful searching
Suggested keywords for more articles like the ones on this page are: RFI
You can get a photocopy of any ARRL published article for $3 ($5 for nonmembers) for each article requested. Contact the ARRL Technical Department (reprints@arrl.org ), 1-860-594-0390) if you wish to get photocopies.
This information was prepared as a membership service by the American Radio Relay League, Inc., Technical Information Service, 225 Main St., Newington, CT 06111 (860) 594-0214. Email: tis@arrl.org (Internet). ARRL HQ is glad to provide this information on the Web free of charge as a service to League members and affiliated clubs.
If you have any questions concerning the reproduction or distribution of this material, please contact:
