John: Traps are small to have minimum wind resistance, weight, and cost. It would be possible to build more efficient ones but they would probably be 4-6 inches in diameter and somewhat longer. The e
The ideal antenna drain hole would have a reasonably large diameter but would not allow insects to enter and build nests. I believe there is a way to accomplish this. There is a material used in sand
Mark, IMO the power dissipated in the Balun will be related to the coax termination impedance at the antenna. If it sees 50 ohms then there will be little current coming back down the shield outer .
I have built and measured several of the K9YC choke designs with similar results to his. However, you can achieve resistances of several thousand ohms in a less clumsy way. I use the small teflon die
You can find information on cores suitable for line choke construction here. http://www.fair-rite.com/cgibin/catalog.pgm#select:freq1 1. Single click Suppression. 2. Click Cables. 3. Click round cabl
My 131 ft crankup contains 2 control relays. I am pretty sure one controls lift and the other controls lower. They are AEG LS-05-10E. I need to know the schematic for these relays, particularly the c
Yagis are usually mounted to the mast at the balance point. This is almost always not the center of the boom length because of the different element lengths. As a result varying wind forces cause sur
Tom: The use of a coil of coax as a choke is a poor solution to the problem of feed line radiation. It is affected by the feed line length and distance to ground. Not only that, it is not well suited
Hector here is the information you requested. The coax wound chokes are self resonant in the measurements and in my opinion will be detuned by attaching coax feed lines and proximity to the boom of a
My Times Wire and Cable catalog says it is 75 ohm -- Dan Hearn N5AR _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@co
I have one of these beams installed about 12 years ago. After some extremely violent winds and snow storms recently the beam overhead truss guy has apparently come loose from the attachment to the ma
Hi Don: I remember 75 ohm twinlead built specifically for RF use. It used rather large stranded wire quite close spaced. It was rather stiff and the plastic coating was not the stuff used in Zip cord
I have a discussion of the 43 ft vertical on our club website www.sdxa.org Click Articals to see it. In addition, I think it is not often realized that the coax feedline outer shield acts as one of t
Jim: I just did a power Point on Yagis including the latest thinking. Will send it to you if you wish. 73, Dan, N5AR -- Dan Hearn N5AR _______________________________________________ ________________
I will wait until tmw to send as I think there may be others who want a copy. It has sound on it by clicking the little speaker. 73, Dan -- Dan Hearn N5AR ____________________________________________
Recently I lost a 6l 20 yagi in a windstorm when my power went off and I could not rotate it into the wind. Some time ago I wrote a short note to post on our www.sdxa.org web page under articals whic
Hi Tom: I believe you are correct, the problem is overheating. K9yc has made many presentations on the topic of wide band baluns and you can read all about it on his web page. He is right on and I ha
George, I know that SS is considerably weaker than the high strength alloy bolts in the OR2800. I have an OR2800 on the ground and it does not appear practical to ream the holes for larger bolts. I w
Jim, I also have Sevicks book. The W1JR job on page 33 is widely used, easily built, and is commercially sold by Balun designs. The small teflon coax is unbelievably rated at 9kw at 10mhz. I have bui
I use 2 of the 4 pin trailer connectors sets on my rotator cables. Hook one of the male connectors to the rotator and the female connector for the other cable to the rotator. You can then easily conn