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KB1SYV · #11 10-27-2009, 10:10 AM

The other day when I bought the whole thing, the seller gave me one of those mondo 3 magnet mag mounts. I nitially just tried to put it on my A/C unit and go from there, well as I've learned, that's not gonna work. I really have no way to increase it, maybe radials???

moleculo · #12 10-27-2009, 10:57 AM

The A/C unit is nowhere near enough of a groundplane to work good on 20 meters and 40 meters would almost be a waste of time. There are a few ways to accomplish what you're trying to do, though. One way is to use some kind of bracket, mirror mount or something similar and attach it to some type of stand, tripod or something. Then you run as many wires as you can on the ground out from the ground side of the bracket. If you can't do that, try to figure out a way to attach some wires to the A/C unit and drop them down. They don't have to be heavy gauge wire...something inconspicuous will work fine...just make it as long as you can.

KB1SYV · #13 10-27-2009, 11:53 AM

Does it matter that the antenna doesn't even clear the roofline? Remember my antenna is basically inside a stone box. I don't have any ground around my window, I'm on the third fllor. About 15 ft down is the roof of the 1st flor, could I drop a half dozen wires to that roof? Would it accomplish the same?

KB1SYV · #14 10-27-2009, 01:29 PM

Luck has hit, finally!!! I talked my landlord into roof access, which is about 40 ft, with one stipulation. He doesn't want it more than 3 ft above the roof. My buildings roof is flat, and the connected adjacent buildings roof is pitched. I need to find out what door has opened for me with this opportunity, any ideas?

73,

Jethro

moleculo · #15 10-27-2009, 02:02 PM

Oh hell...now you can stop messing around with that hamstick

How big is the roof surface area? You can easily put up some horizontal dipoles 3' off of the roof...no problem. Or maybe a wire loop...or...you have a bunch of options now!

KB1SYV · #16 10-27-2009, 02:07 PM

Cool, I need to talk to him more tommorrow, but I would like to go to him with some sort of cursory plan. I assume the roof is pretty big, conservatively 30X40, I don't know if there is any obstructions up there though. I also don't want to get him skiddish by showing him a plan to take up the whole roof. What can I do without spending too much more and getting multiple bands??

73,

Jethro

moleculo · #17 10-27-2009, 02:24 PM

Build yourself a wire antenna. The cost is minimal and they're easy to build. You probably have enough room for a 40 meter loop. Here is a calculator: Loop Antennas and Calculator

It doesn't sound you have enough room for a 40 meter dipole unless you want to build a trapped or loaded version. You could build a 20 meter or higher band dipole, though. What are you going to use for feedline: coax or ladder line?

KB1SYV · #18 10-27-2009, 02:28 PM

Is there any way I can get something up there that will allow operation on more bands?

moleculo · #19 10-27-2009, 02:39 PM

Quote:

Originally Posted by KB1SYV

Is there any way I can get something up there that will allow operation on more bands?

That's why I asked you what type of feedline you planned on using. If you use some type of parallel feedline (ladderline, for example), you can tune all the higher bands than your antenna is cut for with minimal loss. It will really work well. For example, if you put up a 20 meter dipole, you could use your tuner to get 17m,15m, 12m, 10m, 6m. You could do the same thing with coax, but it won't work nearly as well.

The other option if you use coax is to make multiple dipoles fed off of the one feedpoint. This is called a fan dipole. There are a lot of other types of wire antennas you can make; I'm just giving you some examples.

KB1SYV · #20 10-27-2009, 02:45 PM

I can buy ladderline if it will get me better result's. What could I use as posts to wrap the wire around? I'm probably going to have to do a horizontal. Do I need to wind wire more than once? What kind of gauge wire that will hold up to ice and snow. I have an ldg at897 autotuner without a balun, will I be able to direct feed the antenna to the ladder line, to the tuner? Any suggestion on how I would ground this as well?

thanks for your time and patience by the way.

73,

Jethro

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