This web page was created in July 2004 by consolidating two technical index pages and the downloads page. On 14-Oct-2004 the information about intermod calculators,cavities, duplexers, feedlines, isolators, circulators, preamps, and other antenna system items was split off to the Antenna Systems page. In March 2005 the antenna information was moved to its own directory.
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USA Spectrum Allocation Chart (95kb PDF file)
The official chart straight from the US National Telecommunications & Information Administration (NTIA) Office of Spectrum Management (OSM)
Alternate source - from the NTIA server: http//www.ntia.doc.gov/osmhome/allochrt.pdf (off-site link)
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Repeater Application notes
and Articles offsite link to Chip Angle's web site
Look for the "Repeater applications notes" - proven repeater system design techniques from a VHF / UHF / weak signal / contesting fan and RF design guru
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How
to look up an FCC ID number Sometimes being able to
determine who made that device is sometimes very useful... (offsite link - to the FCC server)
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How to look up a tower location Lists all of the FCC registered towers - broadcast, cellular, everything... (offsite link - to the Berkana server)
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Tower lookup page at the FCC web site (offsite link - to the FCC server)
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ChipDir The Master Chip Lookup Web Site (offsite link to a Dutch server)
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How do I measure sensitivity on this FM
receiver? Measuring receiver sensitivity by Jeff DePolo WN3A.
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Measuring Sensitivity - SINAD vs Quieting There are two standard ways to measure sensitivity, and this article
compares them, complete with clickable audio files... by Robert W. Meister WA1MIK
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Measuring Receiver Effective Sensitivity Repeater receiver sensitivity on the workbench is irrelevant - all that really
counts is how well it works at the repeater site... by Chris Boone, WB5ITT |
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Speaking of Preamps... An interesting discussion thread about 900 MHz preamps extracted from the AR902MHz Yahoo! Group. The information
presented herein is applicable to other bands as well. |
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Fundamentals of RF and Microwave Noise Figure Measurements - Application Note 57-1 712KB PDF by Agilent Technologies (the old HP Instrument Division)
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10 Hints for Making Successful Noise Figure Measurements - Application Note 57-3 967KB PDF by Agilent Technologies (the old HP Instrument Division)
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Practical Noise-Figure Measurement and
Analysis for Low-Noise Amplifier Designs - Application Note 1354 1.7MB PDF by Agilent Technologies (the old HP Instrument Division)
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Resolving high-band paging
transmitter interference by Bryan Dorbert N3ST
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An explanation of Audio Processing A reply by Jeff DePolo WN3A.
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900 MHz Frequencies to Avoid When You
Set Up Your New Repeater There's a lot of grunge on 900MHz and amateur radio is
secondary there, and we just have to avoid it. Here's a list of channels to avoid, plus some
important information that restricts amateur use in some areas of the United States...
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While it's not worth a separate article, you don't want to have a UHF repeater input
between 446.0 and 446.100. The European FRS radios (the service is called "PMR 446") uses
8 narrowband channels in that range (complete with user-selectable CTCSS codes),
specifically: (1) 446.00625, (2) 446.01875, (3) 446.03125, (4) 446.04375, (5) 446.05625, (6) 446.06875, (7) 446.08125, (8) 446.09375 ... sounds
like a good area for digital / Dstar / P25 repeater outputs or point-to-point packet links.
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How to install RF modules and transistors A step-by-step procedure from the experts by RF Parts company
Original source - from the RF Parts server: http://www.rfparts.com/install.html (off-site link)
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The FCC Class of Station Code list
Ever wonder what an FB2J, or a FB4, or a FB6L is? This is a local copy of the one at the Percon Corporation web site.
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Understanding the FCC Transmitter Emission Codes
Ever wonder what 20K0F3E means, and how it was invented? This is a "Rosetta Stone" article.
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How about 1200mHz? Any thoughts on this? A reply by Jeff DePolo WN3A.
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1200 MHz / 23 cm repeaters in the U.K. An article by Andy G8VLL.
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Terminology used around repeaters
An on going glossary updated regularly. Contributions welcome.
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Why should you really spend $50 to re-crystal a channel element or ICOM? by Kevin Custer W3KKC, Eric Lemmon WB6FLY, Jeff DePolo WN3A, Robert Meister WA1MIK and Mike Morris WA6ILQ
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Flat Audio, and Pre & De Emphasis explained. By Morris, DePolo, Schmid, and Custer.
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Pre & De Emphasis, Explanation and Assistance: Running
the Numbers. By Matt Lechliter W6KGB
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More on why Pre-emphasis & De-emphasis,
with examples on the Motorola Micor By Paul Sexauer K3VIX
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Amateur FM and Repeaters from QST magazine 1969 By Les Cobb W6TEE
This article is an overview of Amateur FM and repeaters and despite the date, the ARRL didn't
"get" repeaters and remote bases until about 10-15 years later (Wayne Green and 73 magazine
were the driving force as he ran a slew of FM and repeater articles in the late 1960s and
all of the 1970s).
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FM Standards Article from Ham Radio magazine
1970 By Les Cobb W6TEE
This article is a technical analysis of the wideband (+/-15KHz) and narrowband (+/- 5KHz)
modulation standards. With the conversion from narrowband to even lesser deviation
standards it's worth reading to understand the history and to see where things
have come from.
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The Remote Base - An Alternative to Repeaters... from Ham Radio magazine 1977 By Gordon Schlesinger WA6LBV, and
William F. Kelsey WA6FVC
Recommended reading for those wishing to relieve congestion on the vhf bands - a definitive
description of the difference between remote-base stations and repeater stations.
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Two Meter FM repeater separation -
20 kHz Yes, 15 kHz No... from Ham Radio magazine 1985 By By Chris Kelly WD5IBS and Virgil Leenerts WØINK
5 kHz deviation with a 3 kHz audio cutoff creates a signal at least 13 kHz wide, counting only the first set of sidebands. That's why many states went from 15 kHz to a 20 kHz channel bandplan on 2m. This article gives the theoretical information and proves the point (through VHF FM receiver selectivity measurements) that you have more usable repeater pairs using 20KHz spacing than with 15KHz spacing.
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How much PL Deviation should I run? by Kevin K. Custer W3KKC
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Eliminating the long squelch noise bursts when using CTCSS (PL / CG) The use of "AND Gating" of the logic signals, by Kevin K. Custer W3KKC
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Motorola PL and DPL codes The standard list of codes extraced from a Motorola RSS Help file, compiled by Robert W. Meister WA1MIK
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How do I link two or more systems
together? by Kevin K. Custer W3KKC and Michael R. Morris WA6ILQ
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How can I remote a phone line to my repeater
site? by Kevin K. Custer W3KKC
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Programming your repeater controller
without a radio or a phone line. by Mike Morris WA6ILQ
While oriented towards an Scom controller the article has enough information that you could use the techniques and circuits to program ANY brand of controller.
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Repeater Courtesy Beeps by Mike Morris WA6ILQ Sample tone info plus telephone call progress tone specs
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How do voting comparators
work? by Mike Morris WA6ILQ
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How does a Voter and Remote
Receiver work ? by Duane Hall and Kevin Custer W3KKC
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Passive Repeaters by Kevin K.
Custer W3KKC
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Some Thoughts on Solar
Power and Other Off-The-Grid Repeaters by Mike Morris WA6ILQ
Some ideas on what to do when there's no power line...
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Weather radios, SAME decoders, and
amateur repeaters by Mike Morris WA6ILQ
Yes, you can have a weather alert or warning receiver activate your repeater - as
long as you stay withing the rules...
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A list of the USA Television
Channels... from back in the days when there were 83 channels and 800Mhz was TV...
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A Phone Line Busy Sensing
Circuit By Monte Smith, WDØDIR, from
ACC Notes, April, 1986
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A very interesting
Pacific Bell press release from 1990 that a number of California repeater and
remote base operators have used to force Pacific Bell to grant residential phone
rates to mountaintop radio sites. The arguments made are simple and compelling
and might work anywhere. Well worth reading! (the monthly rate certainly has
changed!)
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AC Power Information - Safety Issues
when dealing with commercial AC power. by Mike Morris WA6ILQ
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But it's only a couple of dB ! by
Mike Morris WA6ILQ Feed line losses DO add up!
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dB to voltage conversion table
(both 50 ohm and 75 ohm) by Mike Morris WA6ILQ
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Return loss to VSWR table by
Mike Morris WA6ILQ
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A catalog of GE miniature and sealed beam lamps 32.9 MB PDF donated by A. Nony Mous
Info on pilot lights, round and rectangular sealed beam headlights, PAR series lights, Festoon lights, neon lights, electronic descharge fluroescent lamps, and more.
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Building Your Own CATV Hardline Matching
Transformers By Kevin Custer W3KKC
75 ohm TV hardline is cheap and here's how to match it to a 50 ohm system
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CANUSA Heat Shrinkable Tubing By Kevin Custer W3KKC
Great for sealing antenna and coax joints
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Poor Man's Spectrum Analyzer Spectrum
Analyzer Kit by Science Workshop (offsite link)
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Modulation Spectrums By
Robert W. Meister WA1MIK
How audio frequency, filtering, and deviation affect your transmitted FM signal, how
to prevent excessive deviation and splatter, shown with dozens of spectrum analyzer
traces.
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Why every ham owes Art
Gentry W6MEP a dept of thanks The story of how one man started
a repeater revolution. By Bill Pasternak WA6ITF (From QST March 2004)
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A very good primer on
basic, single-supply, op-amp circuits 160kB PDF file
A Texas Instruments Application Note (number SLOA058 dated November 2000).
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Op-Amp Design Reference 2MB PDF file
Another Texas Instruments Application Note (number SLOD006B, dated August 2002). This one has a
lot more technical detail info than the primer above.
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Allied Electronics Data Handbook, 2nd edition
(1958) 6.7MB PDF file
A classic electronics reference, about 64 pages. Chock-full of old component and wiring color
codes, formulas, conversion tables, coil winding nomographs, tube substitution data, etc.
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Allied Electronics Data Handbook, 4th edition
(1964) 3.8MB PDF file
Newer version of the above reference, about 88 pages. This one includes transistor circuits.
Sold for a whopping fifty cents when new. Very nice scan.
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