Bill and all, If I change from 5" to 8" the reactance moves the right way, but the resistance moves the opposite direction. The net result is that the model is a little closer to the measurement, but
Equivalent diameter of Rohn 25 This is where I found the reference to 5" (5.25" actually) as the equivalent radius of Rohn 25 tower: William F. Cummings (K6MYH), "Tower Equivalent Radius," Conference
I need to be a better editor of my own material! ... _______________________________________________ Antennaware mailing list Antennaware@contesting.com http://lists.contesting.com/mailman/listinfo/a
Let me correct any confusion I caused... In my contribution to the discussion of tower equivalent cross-section, all my references should be RADIUS, not diameter. Thus, the reference uncovered by Bil
I finally took some time to review my modeling vs. measurement of the feed impedance of my 160M vertical. To review -- my original model showed 39.8 +j48 ohms at 1850 kHz, with 8" diameter (yes, diam
Notes on the dual-feed K9AY Loop.... "Dual feed" is the equivalent of a remote R +/-jX termination, plus the ability to compensate for asymmetry and systems losses such as wire loss, hence the extrem
Both feed and termination will see the same ground loss, so Rterm is 500 ohms minus the total ground loss, not half of it. ...K9AY _______________________________________________ Antennaware mailing
See: http://www.aytechnologies.com/TechData/K9AYLoopArrays.pdf This is a presentation on arrays of K9AY Loops prepared for the W9DXCC meeting a couple years back. While working on the article, I put
John, In general, tribanders with longer elements should be more efficient, and generally get better reviews by their users. Of the ones you mention, the TH-2 and TA-32 fit the above criteria, but do
Paul (KG7HF) ________ Radials for verticals make all the difference in the world, just like height does for horizontal antennas. Before writing off verticals, note one of my experiences: In 1985 aft
I've owned a Hy-Gain Explorer 14 and now have a Cushcraft X-9. Both worked on 12M; the EX-14 even had some F/B. Only used them a few times to work DXpeditions when another antenna was not available.
Paul, Best info is in W7EL's Notes for the two log periodic examples in EZNEC (LogPer and LogPerTL), one with interconnecting wires, the other with transmission lines. Gary K9AY _____________________
Dave, EZNEC does this automatically if you recall a saved trace and add it to the current trace. If you are overlaying exported bitmap files in a graphics program, choose a fixed outer ring value in
Dave and all, To quote from W7EL's Help File: "Note that .pf format files saved as 'trace files' are not graphics files. They are binary files which contain only numerical field strength data, and no
Most graphics programs let you rotate, flip and change colors. One handy action is to show all patterns of directional arrays -- e.g. to show the four directions of a 4-square, I simply take the orig
Dan, You can examine the stub-tuned reflector behavior using the EZNEC Transmission Line feature. The K3LR et al approach looks best to me, with the reflectors tuned for maximum smoke, but there are
Fellow hams, Jerry Sevick, W2FMI, one of ham radio's great technical contributors, has passed away. I received word from his family that Jerry died peacefully this past Sunday at the age of 90. I hav
Dave, One of my past projects was a no-radial multi-band vertical with a feed similar to what you propose. I found two alternatives for isolating the feedline. The first was a 1.77:1 transmission lin
One more option is a ground plane, with two, three or four sloping radials. With this configuration, you can achieve a low-VSWR match by adjusting the angle of the radials, and coupling/common-mode o
When the finished product works exactly as modeled, it is ALWAYS a combination of: a) The model's ability to represent reality. b) Consistent, predictable behavior of the construction medium. c) The