A Mechanical Engineer friend built a tilt mechanism for a 70 ft R25 Tower using VERY HEAVY DUTY material. I *think* the basic R25 Tiltover mechanism is meant for 40 ft or less. Tom N4KG _____________
I set my tower legs on bricks in the bottom of my base hole, then poured in several inches of gravel to allow for drainage. Tom N4KG ________________________________________________________________ G
Interesting idea Thor. If you like, you can line up REFLECTORS for each band with 0.15 WL spacing to get directivity on each band without interaction. Lower frequency Directors create destructive int
Yep, reflectors can be lined up in band order with virtually no destructive interaction. I built a 12, 15, 17 2L reflector Yagi using a 17M DE fed with ladderline and separate reflectors. Also, look
On Mon, 01 Apr 2002 13:34:10 -0500 Neil J Nitzberg <njn2@adelphia.net> writes: N4KG: It is a popular MYTH that a LOW Horizontal LOOP produces low angle radiation. A 1 WL Loop close to the ground prod
N4KG: My solution to going around antennas / guy wires is to have TWO lanyards so that I ALWAYS have a line around the tower. I use a single 10 ft 1/2 inch nylon rope folded and looped around one D r
I have a 10 ft mast holding / storing two 3L20's, a 5L10, and 3L10. It sits in a 30? inch hole in the ground formed by pounding a short thin wall steel tube into the ground, six inches at a time, rem
HUH? Only if you are looking at Force 12 or KLM antennas is this a valid statement. Obviously you have not examined any of the Cushcraft, HyGain, or Mosley antennas which have grounded elements on al
Very effectively. See my article on Reverse Fed Elevated GP Antennas in QST for JUNE 1994 or any of the subsequent ARRL Antenna Books or ARRL Handbooks. Of course the antenna elements need to be conn
The HAM series rotors have ~48 bearings in the races. With the weight of the mast and beam sitting on the rotor, I expect it makes pretty good contact. I measured a very low resistance across a spare
I assume they intend for the 2L40 to be operated as a Reflector array. They are giving you the option of making the 30M antenna EITHER a Reflector or Director array. A reflector (tuned below the band
I thought so. That makes it 2 for 2 in spotting the physicists on TT :-) Most engineers stop their analysis when they reach the point where the design is 'good enough' to meet requirements. Physicist
How about a 'Cherry Picker' / Bucket Truck? The feed impedance of a dipole is highly dependent on height above ground. A full size dipole presents a feed impedance of 69 ohms at 0.2 WL (28 ft), 91.6
Here is the data from the original definitive study on Field Strength at 1 mile versus Number and Length of Radials as described by Brown, Lewis, and Epstein in the June 1937 Proceedings of the IRE (
Are the end elements electrically connected to the boom? If so, I see no problem, just follow the PROCEDURE I outlined in my post on the TH6 / TH7. Tom N4KG
The best argument I can think of for using poured concrete in a hole vs. placing a precast block in a larger hole is that for the first case you have UNDISTURBED EARTH around the poured concrete vs.
Most of those discussions were under the heading of Tower Failure(s) or Guyed Tower Reference. I copied most of the posts from early and mid 2001 in a private response, including the recommendation t
least of 18 the XM240 120' have Did you (or anyone) try connecting the XM240 Reflector to the boom (similar to the 402CD) ? Did you (or anyone) try changing the termination on the XM240 feedline (sho
The most obvious differences between the XM240 and 402CD are that the XM240 has more robust construction and that the reflector is INSULATED from the boom whereas the reflector of the 402CD is electr
On Sun, 07 Apr 2002 14:35:16 -0400 Pete Smith <n4zr@contesting.com> writes: A 40M rotary dipole is a very effective antenna, especially when placed above 70 ft high. There is a lot of benefit to be d