|
My vertical blew down!!!
|
My vertical blew down!!!
|
My vertical blew down!!!
Excuse me very much, but isn't shipping for exotic alloy pipe going to
be more expensive than the pipe itself? That's not negative, that's practical! The Eternal Squire |
My vertical blew down!!!
My suggestion would be the following:
Cut that buried 1" pipe about a foot over the ground, to serve as a ground support for your new antenna. Get a heavier steel pipe (ca 1"3/4 - 2") that will fit over the 1" pipe, and perhaps 10 foot long. Get a cheap fiberglass (not carbon) fishing rod ca 18 feet long, (1/4 wave on 20m) Tape a 1/4 wire radiator to the fishing rod, and feed with coax at bottom of rod. Attach fishing rod securely to the top of your new mast pipe. Rise the pipe and fishing rod assembly vertically and guy at the point where the fishing rod is attached. Now you can run elevated wire radials along the guy ropes, and you should probably also ground the coax shield to the mast pipe at the feed point. Enjoy! 73 de Hans, SM3PXG wrote: Ground system: 5 foot of 1 inch diameter galvanized iron pipe, halfway stuck in ground with concrete. 9 foot carbon fiber fishing rod, handle epoxied and inserted into pipe a wire is attached to copper pipe and run up to end of rod. Hot end of coax connected to bottom of copper pipe Rope guys are econnected to the top part of the shaft coupler, as the middle of the shaft coupler is predicted to be weakest point. Sigh, The Eternal Squire |
My vertical blew down!!!
Now THAT's a practical idea...
Thanks! The Eternal Squire |
My vertical blew down!!!
Hi,
Given the circumstances you have.. I would give some thought about putting up a vertically mounted Small Transmitting loop such as the MFJ. Will it work as good as a Vertical? , not one that has a good radial system under it and a clear shout at the horizon.. but it sounds to me like it might be just right for your needs.. Give them a Look I built one here and used it for a couple of years mounted only 3 feet above ground and it worked surpizingly well , considering it's size about 3' in diamiter . If I were in your situation I'd mount it about 1 or 2 feet above the trailer roof. Hope this helps, 73 DAVE KC1DI On Fri, 02 Dec 2005 21:28:26 -0500, wrote: Hi, It seems that my location boasts 60 to 110 mph winds on a regular basis. I had put up a 1/4 wavelength 20m vertical with 1/8 wavelength radials elevated at 7 feet, with rope guys... and the wind blew it apart like so much tin foil! Does anyone know of a decent commercial design for less than $1000 for a free standing 30 to 40 foot support that can take this darn wind??? Thanks, The Eternal Squire -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ |
My vertical blew down!!!
I have no trees, streelamps, telephone poles, or anything higher than a
7 foot trailer. That was why I was considering a vertical. For practical purposes anything higher than 40 feet is forbidden and 25 foot is as high as I practically dare do. You could use a mobile antenna on the trailer and have a decent signal. From what I understand, dipoles are not effective below 1/2 wavelength above the dirt, but verticals can work well fairly close to the dirt if they have to. From what I hear inverted vees are slightly better than dipoles but slightly worse than verticals at low altitude. It all depends where you are talking. For NVIS, even a low antenna will do ok. I've run quite a few low dipoles in portable use, and never had any problems. 1/2 wave up? If that were true, my dipoles here at the house would be no good. They are only at 40 ft. Thats barely more than a 1/4 wave up on 40m. 1/8 wave on 80m... I have no trouble at all, and that includes dx. I can work dx on 80m with only 100w no problem. In general, dipoles are better than inv vees at any altitude. At low heights, you have less ground losses, and the antenna is higher above ground in general. But, thats not to say an inv vee won't work ok. It will. A flat dipole is best though, if perfection is desired. Slightly less than low verticals? Who can say. It could be much worse, or much better, depending on the quality of the vertical, the band and path used, etc...In general when camping, I'd rather run a low dipole, than a ground mount vertical with few radials. Any vertical not ground mounted, I consider a ground plane, and it must have resonant radials. Again, it could be better, worse, or about the same... :/ Depends on band, path, etc.. The low dipole would smoke the vertical on NVIS on 40/80, but the vertical might win to long haul dx late at night if it's any good. My wife really doesn't care about money as much as she cares about waste. If I can make my setup working with the stuff I already bought then great... At this point I am considering just throwing in the towel and raising a 20 foot iron pipe to mount a 20 meter inverted vee... sigh. Probably what you should have done in the first place...:/ Would work better than most anything else you will likely try. I would have made my usual fanned paralleled dipoles fed with a single coax if I could squeeze the room, and had a place to tie the ends off. Sounds like you don't really.... 20m is my favorite band, followed by 40 then 30. Why not use the "no radial" verticals? IE: cushcraft R7, and others of it's ilk? Those are good for what you are trying to do... And they will usually work better than a vertical that needs radials, but doesn't have all it needs due to a limited location. Yes, you can use helical radials, radiator, but don't it expect it to be a world beater. A simple dipole would probably eat it for lunch and be cheaper and easier to build. I've used quicky dipoles portable, no higher than my own height, and had no trouble talking. And that was mainly on 75 and 40. One time I did that only running a yeasu ft-7 with 10w output, and had no trouble. That was at Lake Amistad, out in the psuedo desert. Not many trees where we were. I found a tall 6-8 ft stick, and use that to support the dipole. The ends were tied off to low bushes, or whatever.. Even with 10w, I was averaging S9 or so to most people around the state. Not too bad. Would have been 10-20 over 9 with 100w probably. MK |
My vertical blew down!!!
|
My vertical blew down!!!
I actually found what I hope is a solution. The KANGA 33' Telescoping
Fiberglass mast for $99 is guaranteed against breaking or shattering in winds such as I might encounter, free replacement of broken sections if this is so. Weighs only 4 lbs, base is 2 inches. K1CRA, the distributor, suggested that all I needed to do was mount this against my pipe mount with a 2X4 and U-bolts. He also distributes a sealing agent for permanent installations. With this, he said, all I needed to do was run wire up the mast and work against my pipe mount as connected to the overall ground systems. Sometimes it is the obvious which is the hardest to conceive of. I always though high winds and high heights always needed big iron (or copper), but I never thought that something made of an aerospace material would be within my reach... let alone that of a ten foot Pole or a seven foot Texan... I'll let you know how it goes... Thanks, The Eternal Squire |
| All times are GMT +1. The time now is 03:50 PM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com