Author: thompson@mindspring.com (David L. Thompson)
Date: Fri, 1 Feb 2002 17:21:21 -0500
N4KG and W4ZV are right. The real high antennas can be at a disadvantage after the bands open. I had a 7 el 10 meter beam at 70 feet in 1970 for the CQ WPX SSB and I had a great signal into Northern
I kept track one year in the 10 meter contest of which antenna I worked stations on. This was in a period of very disturbed conditions and moderate solar flux. I had 7 elements on a 42 foot boom at 1
I suspect that this is not so much a matter of where the main radiation pattern is, as where the nulls are in respect to the incoming angles. Very high antennas have better gain at the lower angles i
In getting back to the basics, I submit that at heights over 4 to 6 wavelengths above ground, the antenna is in "free space" and that's why the "nulls"are filled in. Also, at these heights, in free s
So has anyone tried using an elevation rotor on a high yagi? Why couldn't you have the best of all worlds with a high yagi and point it up for high arrival angles? Michael WY6K ______________________
Nulls are not caused by "angle of elevation" of the yagi boom. For all practical purposes their angle is fixed by the frequency and height of the antenna. They are caused by the cancellation of waves
N4KG answer below. up That's one of those 'good ideas that didn't work' The problem with tilting is that while you may get a slight increase in gain on the incident wave, you get a LARGER DECREASE in
A lot higher than 4-6 wavelengths. I ran a 10m yagi in EZNEC at 200 feet above ground, and both the deep nulls and reflection gain were still fully evident. 73, Pete N4ZR Sometimes a tower is just a
I have always dreamed about a crank-up tower and an elevation rotor on a ten meter installation. At one time long ago K1AS had a converted "Moonraker" beam that was mounted on a slightly bent mast. H
The null-filling idea depends on one of two concepts: 1) ground clutter or irregularity filling nulls because the ground is not a smooth reflecting plane. Effects of this can be seen with programs li
my biggest ten meter antenna is my lowest... have 4L @ 140 ft 4L @ 50 ft Tribander at 45 ft and 6L on 42 foot boom at 35 ft... The 6L consistently has been kicking buttock...am anxious to try a two y