Credit this one to W9LT, at my first tower-raising -- since we're talking temporary, he just put a single cable clamp on the guy wire and then tied a rope "above" the cable clamp with a slip knot. Si
In his book Dave Leeson discusses the downward-sloping foreground in some detail (chapter 10). For example, he shows a table of takeoff angle vs signal for a single 14-mhz yagi 100 feet over a 12 deg
But 75-ohm 3/4" CATV hardline is just a hair lossier than 7/8" Heliax at 30 MHz (.3-.35 dB/100 ft), can often be bought for free, and lends itself to inexpensive connector fabrication. 73, Pete N4ZR
Well, here's what I did. RG-213 from the antennas to the antenna switch. At the antenna switch (at the bottom of the tower) I switched to 75-ohm CATV, using a multiple of a half wavelength at the low
Tom, are you saying that, in an extreme case, there might be NO ground connection in the shack, as long as all the local grounds were tied together so that they "move together?" Doesn't there have to
Steve, I think that's too simple. If the SWR doesn't change when it turns, it MAY not be a guy wire problem, but you can't be sure because not all destructive interaction affects SWR,and the placemen
Joe, I certainly don't rule out the possibility of interaction between the EF-240S and the C-3E. In fact, the EF-240S is turned 90 degrees relative to the C-3E precisely because I noticed an SWR pert
These numbers seem a bit extreme, or at least a bit categorical. How many times have you seen a lightning bolt and counted less than 3 before the thunder came. Did it fry your phone? Your modem? Your
On his web site N1LO has pictures of an interesting entry panel and grounding system that he made, using aluminum plate for the panel and what looks like about 1" silver-soldered copper pipe for a co
For a professional,this represents a reasonable approach. But for the person putting up one tower, on limited resources, it seems like overkill to buy 3 cablegrips to use once. When he was helping me
Mine was a pier pin base. We used temporary rope guys till we got the first set of permanent guys on, tensioned them as I described, and went on up. I gotta say, though, that the inner-ear sensations
By coincidence, I just finished modeling both as parasitic arrays for 80m, with a 48-foot spacing, fairly close to what you're describing. The diamond configuration, fed at the top, gave at best abou
Unfortunately, one of them has never used the antenna, and both discuss only the form (far end shorted, near end with only the center conductor connected to the RX) which is nothing more than a very
Unnecessary, IMO. Beaclock.exe does exactly the same thing, in software, and it's freeware. It does depend on your PC's clock to be accurate within a second or two, but that isn't too demanding. Cont
Tom makes an excellent point. Moreover, if the feedpoint impedance is far from 50 ohms, and the feedline is not a half-wavelength or mutiple, the resulting impedance transformation may make it appear
For what it's worth, another supporting anecdote. I have a Force 12 EF-240S, at 104 feet, on a Rohn 25 tower with top guys at about the 95-foot level. Originally, I had 21-foot semi-rigid fiberglass
Tom must've croaked when he saw that. I just retain the good advice I've gotten and pass it along when I can. Seriously, I have no engineering qualifications, but I've owned the Autek RF-1 for years