I'm no mechanical engineer, but memory serves that Rohn 25 should be practically self-supporting up to 40 feet (with no antenna). 2.5 square feet isn't a really large antenna. I've scrutinized these
Well, Ed, I'm exactly where you are -- in transistion before putting up a tower -- but I've been stuck here with temporary antennas for 4.5 years now. Some financial troubles got in my way.... In any
You know, Joe, much of this problem would probably go away if Cushcraft would simply publish a complete schematic (WITH COMPONENT VALUES) of the MN7 (and MN7000). But, those of us who have pestered y
I checked the archives, and I didn't see any discussion of this issue in the fall, so here goes: In the November 1998 issue of CQ Contest (OK, I'm behind), Tim Duffy, K3LR wrote an article about a 3-
I'm no mechanical engineer, and I don't pretend to understand the subtleties of materials and such. But it occurs to me that in order to get sufficient tension on the odd guys (ie 10% of breaking str
Pilots notice this, too. I used to fly out of a small airport that was surrounded by 50-80 foot trees. Once you got down below the treeline, any crosswind correction you were holding had to change fa
Jim, if there's no O2 dissolved in deep sea water, how do deep sea fish breathe? The problem with the deep, open ocean is there's no FOOD at depth, since the source of energy is the SUN. So creatures
I recently put up an attic-mounted delta loop for 10m. It worked well enough that I'd like to supplement it with similar loops for 15 and 20 meters. My loop is gamma-match fed. One problem is that I
Only 100 watts (on a good day). No Amplifier here. Yeah, that's a possibility. But I'd like to see if I can do it without having to switch anything. That makes one less knob to turn in the shack. Bil
I had a similar problem separating a A3S boom splice from one of the booms. The only solution that helped was HEAT. Get a small torch and heat up the tubes thoroughly. If the tubes are nested flush w
I've been using an R7000 for my primary antenna for 2 years. It works OK. It does well on 40m, and works passibly on 20-10. I haven't used it much on the WARC bands. On 40m the low angle of radiation
I'd like to point out that the mounting system for the R7 and R7000 are totally different. The R7 is designed to slip over the top of a mast. This means you have to have some means of lifting the ant
Hmm. I base this suggestion on the observation that others had offered that the beads nearest the feedpoint of the balun were heating up and destroying themselves, while beads away from the feedpoint
Wow! Where do I sign up for that deal? With two $50 bills, I could probably put up an impressive antenna system that way.... Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@radio.org Quote: "Not within a th
That's something of a misnomer. The fiberglass doesn't deteriorate in UV. In fact, it is glass, which stands up to UV quite well. Yup, that's the rub. The boding agent is often an epoxy, polyester or
I'd eliminate requirement #3. Then, I'd put up a 100' doublet, and feed it with open wire or 450 ohm transmitting twin-lead. Run the open wire right to the house, then use a balun before going inside
I know I've suggested this before, but why not use a mix of bead materials? Have the beads closest to the feedpoint be 43 material, and the ones away from the feedpoint be 73 material. This has the a
Let me add something to this. While using two runs of coax will work as described, I would not recommend small coax such as RG-58, nor would I recommend any coax using a foam or air dielectric. Why?
Just don't disconnect them and leave them floating. My only lightning hit was taken as an indirect strike on an 80m doublet at 45 feet. Lightning vaporized the copper out of 45 feet of 450 ohm transm
Well, I'm not a lightning expert, and all the talk about lightning reminds me of a yiddish proverb. But the theory I've heard and understand is as follows: A grounded conductor aloft assumes the same