At 03:36 AM 2004-06-13, David Gould wrote: The question is what to do with the buried radials - should the buried radials be attached anywhere or left independent? Just leave them independent. Depend
At 05:09 AM 2004-03-06, David Gould wrote: Secondly, Does anyone know of a WINDOWS program that does the calculations? The ARRL Antenna Book software includes a program called TLW (Transmission Line
At 12:59 PM 2004-12-03, Dick N3HKN wrote: Looking at the 1/2wave antennas from PAR, or others, my question is - what portion of the 1/2 wave wire provides the maximum radiation? Is it the end third?
At 11:33 AM 2004-12-22, you wrote: A few months ago someone referenced an article in the June, 2004 IEEE transactions on Broadcast (?) with info on a new shortened type of vertical antenna (I believe
Clive, Are you using bare wire? If not, that could account for the low resonance. 73, Terry _______________________________________________ Antennaware mailing list Antennaware@contesting.com http://
Clive, The presence of PVC or other thick plastic insulation can lower the resonance by a few percent. The latest version of EZNEC (4.0) has a provision to include wire insulation in the "Wires" desc
In general, feeding phased arrays at high impedance points can be a problem. End-fed half-waves and bottom-fed bobtails have the same issues. Normally, with verticals fed at a current loop (e.g. 1/4
Dave, My EZNEC model may be a little different than yours. I used 3 sections of 16 feet each with 2.5, 2.25 and 2 inch diameters (64 segments each), then inserted a 0.25 foot section of 2.5 inch (1 s
The model sources in NEC are either current or voltage sources, so are effectively either infinite or zero impedance. You may note that the gain of a modeled antenna is independent of the type of sou
Jim, I assume we're talking about EZNEC, when plotting 3D patterns. (Other programs may be similar.) In the real world, all antennas have loss (conductors, earth, resistive loads, etc.), so this is n
Is the 100 ohm feedpoint impedance a measured value? The parallel 75 ohm lines in the original design would form a 37.5 ohm line and one quarter-wavelength of this would transform a 28 ohm feedpoint
Kari, This antenna will have many lobes in all directions on 20m and higher bands. Some of them are at low angles and may be useful. Other lobes will warm the clouds. (For Kari, I attached .jpgs of t
What you are suggesting seems quite feasible, but you will probably have to place the capacitor in series with the feedpoint (and the series inductance) to achieve your goal. Of course, you may also
I'm not too familiar with the specifics of these antennas, but as long as they are fairly close to the same size (in wavelengths) and similar feedpoint impedance on each band, you shouldn't have too
The absolute length of a segment really isn't the issue, it's the fraction of a wavelength. With NEC-2 based models, you can get reasonable accuracy for simple antennas (dipoles, verticals, inverted
HyGain marketed these in the late 60's. I know a ham who still has one that he acquired as military surplus. See this: http://www.qsl.net/n2ckh/HA4000.htm They have replacement tapes here: http://www
I agree with all of Guy K2AV's comments. I have even crudely modeled the wire mesh backing the stucco walls of my house. 8-( In addition, it is good to check what happens to the tribander pattern and
Brad, You left out a few specs on your antenna system. Are they separated by 1/4 wavelength? Do you have 1/4 wavelength 75 ohm lines connected with a coax-T and an additional 1/4 wavelength of 50 ohm
The idea of the 75 ohm lines is to raise what might be a 50 ohm feed to 100 ohms so you can parallel the two feeders and get somewhere near 50 ohms again. However, as the model shows, given the effec