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Shortwave Antenna

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Post by tuberadiogeek on Thu Feb 14, 2013 12:26 am

I'll hopefully be getting my first shortwave radio, an S-120 and i was wandering what the best length wire antenna is to use and what size wire is ideal? Right now i have 100 ft 24 gauge speaker wire in mind Also what all can i likely hear on SW living in North West Ohio? Ive read old topics online about SW listening but i'm sure there have been changes since those were written. My back yard faces to the west where my antenna will be.
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Post by Guest on Thu Feb 14, 2013 12:43 am

Here is a link to a site which will help you calculate the antenna lenght;

http://easycalculation.com/physics/electromagnetism/antenna-wavelength.php

And a better one;

http://www.athensarc.org/UnderstandingAntennas.asp

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Post by Resistance is Futile on Thu Feb 14, 2013 1:05 am

Calculations for antennas are used to create optimal reception, especially for the avid shortwave enthusiast. You can enjoy the experience of hands on. Me on the other hand use calculations only for transmissions. (Ham Radio) I have a Hallicrafters SX99 and 120 and only use a hank of wire, and notice no appreciable difference, unless you intend looking for that elusive signal. there is no ideal wire size, you could use 6 gage wire or 32 gage, in fact most antennas have a copper coating over steel wire for added strength. And steel is electrically less conductive than copper, so the copper plating is used because it is more conductive. And the higher you go in frequency the more skin effect comes into play where all the electricy travels on the surface of the conductor and not inside the conductor so the size is of less importance. (That's at much higher frequencies though)
The area of the country is of insignificant value because of the Ionosphere. Most short wave doesn't travel as ground waves, but as reflected waves from the ionosphere. If you were along the coast you might get signals from other countries that are weaker but its doubtful.

Now the length of the antenna can effect gain, but it has to be based on a multiple or submultiple of the electrical length of the frequencies desired. An outside antenna can only be so long so it has limits. A happy medium has to be settled upon, or it will drive you nuts in adjusting its length for efficiency. That's where antenna tuners come into play.
look at this topic for further info on antenna length.
https://www.tuberadioforum.com/t1932-multi-tap-antenna
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Post by N7ZAL on Thu Feb 14, 2013 11:26 am

What you can hear is a function of the frequency and the propagation. As mentioned there are various antenna lengths used, depending on the frequency you want to listen to. An antenna cut to the proper length will give you better reception on that particular band. There rae many multiband antennas out there and a good source of information is the ARRL Hand Book. You can either use a multiband antenna or an antenna turner.
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Post by tuberadiogeek on Mon Feb 18, 2013 4:57 pm

With that said, that leads me to my next question (i know its been a few days) I found a 100 ft roll of galvanized steel electric fence wire at TSC for 3.00, which is dirt cheap.. will i notice any difference in reception between that and copper speaker wire? Or should i get the speaker wire which is 7.00 for 100 ft, but i can actually combine both sides to make closer to 200 ft as i already have wire for a ground.
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Post by N7ZAL on Mon Feb 18, 2013 7:10 pm

I think it will be fine, as long as it is cut to the right length.
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Post by tuberadiogeek on Mon Feb 18, 2013 7:30 pm

Well a quarter wave for 2 mhz will be 117 ft, and 100 will be pretty close.. so i guess it depends if i can get out to a TSC store or not.. as i generally avoid going to stores unless i have to bc i usually have to ride the bus.. so i buy certain things online when i can.
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Post by N7ZAL on Mon Feb 18, 2013 9:05 pm

You could make an antenna tuner.
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Post by tuberadiogeek on Tue Feb 19, 2013 9:39 pm

Despite this crazy weather i made it out to TSC and got a 100 ft roll of galvanized steel electric fence wire. I added around 10 or 15 ft of copper to it by connecting the wire s to a bolt (not galvanized) and then securing the copper under a washer and tightened down nut, then ran down a 2nd nut and washer to leave space so the steel couldnt touch the copper then did the same with the steel wire.. It looks kind of funny but it should get the job done. The bolt may rust after sometime but i'm not too concerned about that at the moment. Now just have to wait til it warms up a bit to get the wire strung out.
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