RF Cafe Software
About RF Cafe
1996 - 2022
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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|January 1954 Radio & TV News|
These articles are scanned and OCRed from old editions of the Radio & Television News magazine. Here is a list of the Radio & Television News articles I have already posted. All copyrights are hereby acknowledged.
Coaxial cable is the most familiar form of RF transmission line for most people these days. Up until 2009 when the U.S. switched to digital television (DTV), there were still a fairly large number of people who had the old 300 Ω twin lead cable running from roof-top antennas to TV sets. Over-the-air reception has petered off precipitously since then. Coaxial cable is undoubtedly more convenient and forgiving regarding routing since proximity to structures - particularly metallic components - than twin lead. Good quality 300 Ω twin lead cable (~30¢/foot today) used to cost less than good quality 75 Ω RG59 cable (~12¢/foot today), but just a couple decades ago when twin lead dominated, the opposite was true. What has not changed is the insertion loss of 300 Ω twin lead cable is typically around 2 dB at VHF TV channel frequencies (54-210 MHz), and 450 Ω ladder line (twin lead on steroids) is about 1/2 or less of that (see "Loss Figures for 300 Ohm Twin Line"). Insertion loss on RG-59 coaxial cable is around 4 dB/100' in the same band (RG-6 is ~3 dB/100', and RG-11 is ~2 dB/100'). The lower you go in frequency, the lower the loss in both cable types, but twin leads gets better faster.
Federal Telephone and Radio Company Ad
North, East, South, West ...
Wherever there are TV customers ...
Federal has a lead-in for the finest VHD-UHF
Whatever the area or atmosphere ... city or fringe ... rain, snow ice, heat, dust, salt spray, polluted air or radiation ... you'll find the answer in these quality-controlled cables by Federal -
For Community TV it's Federal's "Big 5"
K-14 - 71-ohm shielded primary transmission line for community distribution systems. Famous for lowest line loss, long cable runs and fewer amplifiers required. Capacitance: 21.5 mmf/ft. Attenuation DB 100/ft: .57-50 Mc; .90-100 Mc; 1.42-200 Mc; 2.3-400 Mc.
RG-11/U - 7 5-ohm shielded low-loss coaxial. One of the best small-diameter cables. Tops as a community TV secondary lead-in. Seven strands #26 tinned copper. Capacitance: 20.5 mmf/ft. Attenuation DB 100/ft: 1.5-50 Mc; 2.15-100 Mc; 3.2-200 Mc; 4.7-400 Mc.
RG-59/U - 73-ohm coaxial TV lead-in cable. Highly efficient as a community system pole-to-house tap-off. Meets all needs wherever a high-grade installation is a must. Capacitance: 21 mmf/ft. Attenuation DB 100/ft: 2.7-50 Mc; 4.0-100 Mc; 5.7-200 Mc; 8.5-400 Mc.
K-111 - 300-ohm shielded, balanced TV lead-in developed by FTR. Minimizes noise, snow, ghosts due to transmission line pick-ups. Ideal for many areas where good TV was impossible before. Capacitance: 4.2 mmf/ft. Attenuation DB 100/ft: 3.4-100 Mc; 6.6-400 Mc.
TV-1184 - 300-ohm dumbbell-shaped TV lead-in. A standard low-cost lead-in for areas without unusual conditions. Cinnamon-brown color is highly resistant to ultra-violet. Two conductors: 7/#28. Capacitance: 4 mmf/ft. Attenuation DB 100/ft: 1.28-100 Mc; 3.0-400 Mc.
TV-1182 - 300-ohm deluxe type heavy-duty TV lead-in with 90 mil. web. Insulated with "silver" polyethylene, Federal development that provides maximum weather protection and long life. Capacitance: 4 mmf/ft.Attenuation DB 100/ft: 1.22-100 Mc; 2.85-400 Mc.
Non-Radiating Lead-ins for Multiplex TV Systems
K-125 - 75-ohm coaxial TV lead-in cable. Double-shielded and jacketed. Formerly listed as SP-75.
Use these 2 for Community TV radiation
K-126 - 73-ohm coaxial TV lead-in cable. Double-shielded and jacketed. Formerly listed as SP-76.
K-125 alternates for·RG-11/U as secondary lead-in
K-126 alternates for RG-5S9/U as tap-off lead-in
... "Pipeline" of the Air!
300-Ohm All-Channel Twin-Lead that Laughs at Weather
For Fringe Areas
TV-1182 - Provides remarkably low line loss in fringe areas. Outstanding for resistance to weather and sunlight. Silver-colored insulation blends with any color scheme in home decoration.
K-200 (RG-86/U) - 200-ohm heavy-duty ultra low-loss lead-in. Particularly adaptable to remote-area installations - especially long runs and multi-stack antennas. Also used with rombics.
See your local Federal Distributor or write to Federal direct Dept. D-959
TV-1185's "Silver" pigmentation lets you
Install it and Forget it!
Federal's TV-1185 is virtually a "pipeline" for better-than-ever TV reception ... VHF or UHF. Insulated with the revolutionary Federal-developed "silver" polyethylene, TV-1185 is amazingly tough, flexible and efficient.
TV-1185 leads in Weatherometer tests ... fights heat, resists moisture and other destructive deposits ... minimizes deterioration due to sunlight.
TV-1185 keeps the energy field inside the weather-proof sheath ... providing exceptionally low loss ... more constant impedance ... a better TV picture regardless of area or length of lead. It's easy to install and tight-seal against all atmospheric conditions.
There's no finer tubular lead-in of its type on the market today!
Capacitance: 4 mmf/ft. Attenuation DB 100/ft: 0.5-10 Mc; 0.95-50 Mc; 1.25-100 Mc; 1.7-200 Mc; 2.6-400 Mc; 3.0-500 Mc; 4.5-1000 Mc.
Product of America's leading producer of solid dielectric coaxial cables
Federal Telephone and Radio Company
100 Kingsland Road, Clifton, N.J.
In Canada: Federal Electric Manufacturing Company, Ltd., Montreal, P. Q.
Export Distributors: International Standard Electric Corp., 67 Broad St., N. Y.
Posted June 16, 2015