When I moved to my present location 8+ years ago, I asked myself many of the same questions. I figured I was at the point where age and health meant that tower climbing wasn't really an option and, u
That is the generally-used formula. As you said it isn't an abrupt transition, but the point where the 1/r^2 and 1/r^3 terms in the field strength equations become small enough to be ignored. The rel
Different yes, but if I recall correctly (it's been many years since I have worked on an antenna range) the 2D^2/lambda criterion applies to both cases and is where the deviation from a plane wave is
I bought a 6 in. length of 1 in. pipe and a cap at Home Depot which has worked fine for me at a cost of less than $5.00. I figure that after a dozen or so ground rods I might have to replace the cap
The Hy-Gain AV640, Cushcraft R8 (etc) and some of the Gap verticals have minimal counterpoises and if you elevate the base a bit above the roof, there shouldn't be any problems. I have used a AV640 f
Blair, If you do a Google search on "Smith Chart", you will find many resources about this useful tool to graphically display impedance and how a match can be achieved. Chapter 28 of my copy of the A
I agree. Good show (and a gin pole to end all gin poles). Bob, N7XY _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@co
I have had a AV-640 up for the past 7 years and agree with everything Art says. That antenna is very similar (except for not having traps) to the R8 which displayed very good results in the K7LXC/N0A
I essentially used your option #2, although I picked a shorter piece of pipe for two reasons; the ability to easily mount the antenna while standing on my roof and getting it home from the hardware s
That also wrapped on my computer. With most email programs, using left and right arrows instead of parentheses will usually work even if the line wraps: <http://www.radioarcala.com/nbspStation/Towers
I haven't tried it but saw something about doing that using a soldering gun with the tip removed. _______________________________________________ _______________________________________________ Tower
That's in the US. Some other countries have higher limits. Bob, N7XY _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@c
True, but VSWR can introduce additional loss over and above the insertion loss experienced with a perfectly matched transmission. There's a figure in the ARRL Handbook (Figure 21.5 in the 2007 editio
You might want to reconsider. That switch is only rated to handle ten watts average power: http://www.helmut-singer.de/pdf/hp8761A_8761B.pdf 73, Bob N7XY _____________________________________________
That peak rating is for very low duty factor applications, such as radar, and probably (although they don't specify it) only applies to a very short pulse. Most of the HP components like this were in
Correct. They definitely weren't aimed at (or priced for!) the amateur market in any case. I used a few of these switches in the 1970s to switch between horizontal and vertical feeds in an antenna te
Probably creosote, also used to treat wood for docks and railroad ties. The EPA Superfund folks have been cleaning up the site of a former creosote facility a mile or so from my QTH. They have spent
You probably will have issues doing that. If you could select coax lengths between the tee such that each beam which would present a very high impedance at the tee on the other band, it would probabl