Thanks for visiting W8JI.com!
Search this site using:
Business Page Link CTR Engineering, Inc
Table of Contents page
Most of the recent efforts here have been on transmitting antennas. You can see the progress by clicking here.
|FT1000D Click Mod NB mod|
Cars and Automotive
tremec TKO 600 transmission Shift Problems
I enjoy amateur radio because there are so many things to learn. Amateur radio is also a great fraternity. You can learn a little bit about how I started in this hobby on my BOAT ANCHOR page.
All contents of this site are the property of W8JI, but links from other sites are welcomed. If you have a link you think valuable to others, please e-mail me.
If you copy something from here (and even if you rewrite it) please add a reference link here! Linking improves technical accuracy because articles on this site are sometimes corrected or expanded.
The most important thing any of us can do to make the web an asset is to help each other with review to insure technical accuracy IMPROVES with time! Let's work to make Internet a reliable source of information instead of a collection of folklore!!
Other Technical Info Sites:
Current QRN USA Lightning Storm Maps
For an instant check on USA mainland QRN click on Intellicast or Lightning Storm to a weather map of thunderstorms.
SB-221 Tank Voltages and the parasitic oscillation myth. The real explanations behind amplifier parasitic oscillations and alleged damage by HF amplifier parasitic oscillations. Look at voltage throughout the tank at frequencies between 1 and 300MHz, and decide for yourself. Related article at Arcs, what makes an amplifier arc?
Preamplifiers for receiving. Measurements of receiving preamps. Compare your favorite pre-amp (text corrections 4/27/03)
Arcs, what makes an HF amplifier arc? This explains causes of amplifier arcing in any amplifier, including the TL-922 amp, Ameritron amps, Heathkit SB220 amplifier, and any other HF power amplifier for amateur or commercial service. Simple failures and design or operating shortfalls are often explained as parasitic oscillations
Bandswitch failures the real causes and cures of bandswitch arcing and failures in HF power amplifiers that are often attributed to poor parasitic suppression causing oscillation
How to load or tune your HF amplifier and why an amplifier arcs when tuned incorrectly
Inductors deals with antenna loading coils but also applies to amplifiers
Related page: Inductor spice model
Relays how to speed and sequence amplifier T/R relays and how antenna transfer relays affect amplifier failures
Tank Circuits two models showing tank voltages, currents, loss, and phase shift
Vacuum Tubes how they work in RF power amplifiers and why vacuum tubes arc in amplifiers Includes details on 3-500Z and 8877 3CX1500 A7 tubes. Learn reasons tubes fail in amps
Vacuum tubes, how they convert d-c to RF how RF amplifier tubes convert dc to RF power
VHF Parasitics and general stability. Is your amplifier unstable? If you own a TL922, SB220 series, 30L1, or other amps with grid "negative-feedback" you will want to read this! (rev 5PM Feb23/03) Spice models. The resistor think might be non-inductive might not be what you think. Includes internal photos of various resistors.
Cebik and other short dipoles. feed line and tuner analysis!!
If you think baluns at the inputs of tuners are a good idea, go to this W7EL link and read the section on current baluns. You might be surprised!
Another suggested tuner link is W9CF.
Balun and Core Selection: (mostly receiving) Contains information on core selection for transformers and baluns (it isn't a balum)
Balun, sleeve baluns: How a sleeve balun works and what is important
Balun, transmitting: Testing transmitting baluns and untrue folklore about choke, voltage, and current baluns. Dispelling myth that grabbing coax adequately tests a balun
Baluns: winding methods with toroid cores and debunking myth that a split winding improves performance
Baluns: Common-mode noise. How baluns can help reduce receiving system noise
BALUN TEST: Test data on transmitting baluns.
Beverages: Construction, Endfire Beverages, Broadside Beverages, Beverage Arrays for low band DX and other low noise receiving antenna arrays for 160 meters and other low frequency bands. Also see balun and core selection for Beverage transformers.
Combiner and Splitters: Contains information on Magic-T splitters and combiners, how they work and what they do
Curtain Array: Dipole evolution into Lazy H, Sterba, and other broadside curtain antenna arrays
Detuning Towers: A tutorial with an important correction of the common error that we adjust for minimum current!! (revised slightly Feb 17, 2003)
Gain. Stacking (Broadside) and end-to-end (Collinear) gain. How it works, dispelling the 3dB myth.
Lazy-H antenna: Evolution of the dipole into the Lazy-H and Curtain Arrays
Loading Inductors: A brief tutorial on loading coils (inductors) and inductor Q
Magnetic Loop Antennas: receiving
Mobile and Loaded Antennas: Loading coils, ground losses, and currents in the system. Related page: Inductor spice model
Power Stroke Diesel RF Noise: PowerStroke Diesel noise and how I corrected the problem in my 2003 F-250.
Noise and common mode noise. How it gets into the receiving system Power line and other noise sources
Omega and Gamma Matching: Contains technical information on Omega and Gamma matches, impedance limits, component selection, component failures
Phasing, Crossfire: Contains information on cross-fire phasing and why cross fire phasing is superior for broad bandwidth low-band receiving arrays
Phasing Systems: A quick discussion of phasing methods
Polarization and diversity: Think you can have the best of the two worlds of vertical and horizontal? Think again!
Radiation and Fields: Electric field, magnetic field, Fresnel zone What the terms we use actually describe
Radiation Resistance: A revised (as of Feb 14, 03) tutorial on radiation resistance and how it is used and misused
Receiving and receiving antenna pages: Relative ranking of antennas for Topband DX plus various articles on low-band DX receiving antennas...including low band receiving antennas such as Beverage antenna and Beverage antenna construction. Elongated Loops and other loop receiving antennas such as K9AY, EWE, and flag antennas, small Topband or HF low noise receiving Verticals , my receiving antennas (with a demo), end-fire or cross-fire Beverages, common-mode noise in low noise receiving systems, and more.
Rhombic Antennas Rhombic antenna: Models and theory of rhombic antennas and comparisons of the Rhombic to a standard dipole reference antenna.
Skin depth: The best explanation I have found
Transmitting: Contains information on my various transmitting antennas, including my eight direction four-square
Traps: Measurements and models of traps, including Coaxial and Tribander Antenna traps
Diversity reception "diversity" receiving using stereo along with some sound file examples
How I test receivers
Receiver Tests of some transceivers and receivers. Newly added 756PRO FT1000 MK V Kenwood TS870 (modified)
Receiver IM improvement mods for FT1000 FT1000D
DX Sound files: What some signals sound like here
1000MP MK V....mods for FT1000MKV receiver IM and transmitter clicks
Includes sound files of signals with excessive bandwidth, a technical description of what causes clicks, and mods for the FT1000(D) and FT1000MP.
What Causes Clicks....The technical cause and what we can do about clicks.
Keyclick-MP.... An analysis and patch for the FT1000MP 's infamous key clicks
Keyclicks 1000D.... An easy and cheap patch for the FT1000 and FT1000D
Keyclicks 1000MP MK V....mods for FT1000MKV receiver IM and transmitter clicks
Also see Radios.
Technical article about noise and receiving/ receiving antennas
Power Stroke Diesel RF Noise: PowerStroke Diesel noise and how I corrected the problem in my 2003 F-250
MFJ-1025/1026 Technical Information
Common-Mode Noise issues with feed lines, and how to avoid problems
Barnesville-Lamar County Industrial Development Authority Project Brown Green Power Piedmont Renewable Power Rollcast Energy
all pages ©2003-10 W8JI