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Using longwire in attic help

W

wambulance

Member
Sep 23, 2009
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My original thread on this subject was here.
But I've decided to start a new thread as my original post was in regard to specific equipment, wondering if it could be used, and turned into suggestions and advice on something entirely different. Now that some of the hardware is in place, I wanted to continue down this new path and have new questions.

I've installed 100 ft of wire in the attic, supported by zip ties attached to the beams. The wire is 18 AWG insulated copper.

There is some improvement. What I have noticed is that a lot of signal has cleaned up. I don't see that I can get more on the HF band, but that which I can get is much cleaner and stations that were indecipherable before can now be understood. Towards to upper part of the HF band however (example, CB range 27mhz on or about), the volume is very low. I can hear it, but it's much quieter than with the built in antenna.

I have 300 ft more to add, and I assume that this will improve the antenna due to length.

However, others had suggested that getting the wire outside is best of course. It now turns out that I can get the wire outside and into some trees adjacent to the house. My question is; is it ok to have most of the wire inside and some of it outside, or does it have to be all or nothing? I can get maybe 300ft in the attic and 100ft outside and into the trees. Will the extra 100ft outside be better than inside, or with that arrangement should I just leave all of it inside? Let me know what you guys think.
 

My guess is that the 100 foot outside will be better than 300 feet inside, and I would probably do that instead of the wire in the attic. You can always try the inside seperately and then you can switch between them to see if one outperformes the other.

PR
 
As was said on your other thread, having the antenna outside will beat having it inside, but an indoor antenna is better than none at all. Having some of the antenna outside, and the rest inside, will be better than having it all inside, but not as good as having it all outside.

In an ideal world you would be able to put up a dipole for each band you want to listen to, but that isn't allways practical for most of us, unless you have a lot of space. As a compromise a long wire antenna like the one you have made should work reasonably well on most bands, but will work better on some bands more than others depending on how long it actually is.

If you want to listen to 27Mhz in particular, then the best thing would be to put up a vertical antenna, as most people on 27Mhz will be transmitting using a vertical antenna. If thats not an option then you could make a dipole out of wire, and put that outside if you can, or just put it in your attic. There is a load of stuff on the internet about dipoles if you google it, but to make one for receiving all you really need to know is one simple formula....

300/f = 1 wave length

f is the frequency in Mhz you want to cut the dipole for.

a dipole is 2 1/4 wavelength pieces of wire, so..

75/27.2 = 2.75M

so you need 2 pieces of wire, 2.75 metres long, to make a dipole for CB frequencies. Attach one wire to the inside of some 50 ohm coax, and attach another to the outside of the coax, then plug the other end of the coax into your receiver and you should be hearing CB pretty well. You can make a dipole for any fequency you like, but for the lower part of HF they get very very big. For CB they are relatively small though and should fit in your attic no problem.

I'm a metric boy so the above formula is in metric, I'm not old enough to have ever used feet and inches, but if you prefer to work that way I'm sure someone will come along and give you the measurments in imperial :)
 
Hey, thanks a lot and question answered!

"As was said on your other thread, having the antenna outside will beat having it inside, but an indoor antenna is better than none at all. Having some of the antenna outside, and the rest inside, will be better than having it all inside, but not as good as having it all outside."

So having both inside and outside on one wire is kosher. Going to try that out.

Listening to an English broadcast in Beijing right now, and I'm in Colorado and still only have the 100 ft of wire. I'm really excited now.
 
Keep in mind that the 300 foot wire is quite long for the higher bands and most cb antennas are vertical polaeization, so if you are listening there, it WILL be much lower quality. If you must go this way, a tuner MIGHT be of some help.:confused:

PR
 
Well, the wire is pretty clean, the way it is run, but it is not in one straight line. It runs basically 50' in one direction, then 50 ' back with a 10' space in between, three times with about 1.5' of vertical spacing between each run.

And it appears I spoke too soon, there is some difference from the 100' of wire. What I've noticed is that there is no difference between the wire and the internal antenna at lower frequencies. At higher frequencies (by higher I mean above 9000khz), there is a significant difference between the wire and the internal antenna; namely by cleaning up the background noise significantly. When I had the 100' only, the opposite was true; lower frequencies were cleaned up over the internal and not so much on the higher frequencies. So what I do know is that what I have now is better suited to higher frequencies where the 100' was the opposite. Bizarre? My guess is that it has some properties of a vertical antenna with the wire running parallel to itself at different levels, sort of like a slinky antenna but with bigger spacing (just a guess).

I was listening to VOA at 9885 last night. With the built in antenna, the static made it almost indecipherable. Switch to external antenna and it rings in loud and clear with little background noise.

So much that I still don't understand. Doing quite a bit of reading online, but a big black hole of information on the web has me coming back here to bug you guys with stupid questions :)
 
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The only stupid question is the one that you havent asked yet :)

From what I am reading here an antenna tuner might be a good idea to look at.They help 'tune' your antenna to a given frequency so to say

And for recieve use only they are fairly cheap in price since you are not having to worry about transmitting power...just make sure the tuner will cover the frequencies you are listening to.
 

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