Jim, For lightning, you want to ground the shield both at the top of the tower and the bottom. If the tower is taller than say 100' then another ground 1/2 way down. This keeps the tower and the feed
perfectly and was tuned to CW portion of the 20,15 and 10 m bands. 4:1) and antenna started to resonate well above 29.0 MHz. At the same time the resonant frequency moved higher on 15 m, but is stil
While we are commenting on all types of baluns, you might want to look at February and March 1980 QST, specifically figure 1. In March 1980 by W6TC. I have used this type of balun on two TH6DXX's and
50 or 75 ohm coax.... and anything from yagis, etc. http://www.smc-comms.com/hf10_transformer.php Even has cooling fins on the box. Jim - KR9U _______________________________________________ _______
Ah yes, It is in Ham Radio Mag. Thanks, Bill Jim - KR9U -- I believe Jim meant the 1980 February and March issues of Ham Radio, for George, W6TC's 2 part series on "A New Class of Coaxial-line Transf
Bill, Yes, the same thing. He references the QST articles. Jim - KR9U From: w6rgs@cox.net [mailto:w6rgs@cox.net] Sent: Thursday, November 27, 2014 9:30 PM To: jbwolf@comcast.net; towertalk@contesting
Gentlemen, I'm baffled that so many of us put part of a tower in the cement base when installing a guyed tower. I know I've said it here before, but on most guyed towers, why not use a simple roof mo
I just googled it and it appears they don't call it a roof mount any more. Rohn calls it a Concrete Base Plate. P/N BPC45G. Mine is slightly different in that it has three holes in it to bolt it to t
Kelly, I can't say how a pier pin is supposed to work, whether it should allow twisting or not. In my case, the rotor is down at 66 ft. and I have torque guys at the rotor and also at the 100 ft. lev
I can't speak for all smartphones, but those that use real magnetic information for direction use a magnometer. Some use a 2 axis and some a 3 axis. With the latest chips, there is some compensation
I wouldnt expect your smart phone compass to be more accurate than +/- 5 degs around the circle - at best. On most quality, (read military) electronic compasses used for situational awareness, there
David, The best location for lightning arrestors is at the ground window that enters your home. This should be a well-grounded plate where all RF coax and control cables have lightening protection de
If you do the below rebar grounding, make sure your water system is also grounded at the same potential. Just make sure that none of your copper water pipe is touching the rebar in the cement, the po
Patrick, The problem with your setup is that when you short across the input to the receiver you can easily change the characteristics of the input circuitry and the first RF amplifier. Since the rec
Jorge, when transmitting. Make sure that the power supply voltage doesn't drop when in transmit. For some reason, there might not be enough voltage on the relay to hold it in. This could be due to vo
One of the best auto restoration and repair shops around here recommends spraying WD-40 up into door panels to curtail rust. Jim - KR9U ___________________________ wd-40 was developed for protecting
Warren, I have a friend who was very involved in tests in the Pacific - bikini Is. etc. He was told no autos ran and the power was out for a few hours in Hawaii just after one of the tests. He also h
One cheap way to stop the rotation, and possibly limit damage to the coax is to put a time limit on rotation once it starts. Let it run 15 seconds or so before it disconnects all power. After turning
I believe that was the conclusion that Polyphaser came to in their testing as well; that they are no more effective than a single point. I have had a 14 el, 440 yagi at the top of my tower (@ 130 ft.
About 27 years ago, I helped build a contest station where we used mostly stacked HyGain monoband antennas, and a pair of Cushcraft shorty fortys. On the Shorty Fortys, the hose clamps were tightened