Posted: 1/21/2015 10:51:53 PM EDT
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I was reading in the Wireman's Wirebook V a bit ago....it spoke of a gent building a 2w 160m loop that was pretty killer.(1150'+/-)
I have the room for that and moar. The only problem I will face with a 1w or 2w is the max height I can achieve is about 35' AGL.... what say the Hive? 1wave or 2wave 160m loop? |
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Hi SC, I can't model it, but the 2 wave length loop will have some real gaps on the higher frequency bands. If you are going to dedicate it to160M and 80M it would provide better coverage. Modeling it will tell the tale on the higher bands. If you should decide to do two loops perhaps a loop for 160m and a loop for 80m and up in frequency. They ought to be separated a bit too. hth 73, Rob |
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I think 2 lambda loop will work great but you will need a tuner. It's best if you locate a tuner at the antenna feed point.
I had a full size ( 1 lambda) 160m loop at about 70 ft. It worked great. I was getting S9++ signal reports with only 40 Watts in. It was not a DX antenna but it was a killer for regional (80 and 160m) coverage. Loop antennas are very quiet when compared to dipoles. |
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1005 / 1.8 mhz = 558' of wire for one wavelength.
x 2 = 1117' of wire. That's going to require a lot of real estate. Either way, you'll need a 2:1 or 2.5:1 balun if feeding with coax. Otherwise use 1/2 wavelength of ladder line (600 ohm) or window line (450 ohm). You'll need a tuner either way. |
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It depends on your goals - Local? DX? All-Band?
If you have a 35 ft height, generally speaking, your antenna will be good for DX on 30M and up, relatively poor 40M and down. Relative meaning relative to a Vertical Antenna. Rule of thumb is around 3/8 wavelength height where a horizontal antenna has gain over a proper vertical at low DX angles. This shifts around a bit when you start having gain due to the lobes of the loop, but is of course only in the (hopefully well placed!) directions of the lobes. Like others have said, it really helps to model it up with EzNEC of something similar. Even the free version of EzNEC can handle a simple loop. Personally, I don't see the allure of a loop - as mentioned, your pretty much stuck with requiring balun and tuner anyway to get all band performance, and will end up with an antenna that has gazillion lobes on the medium and higher bands, often nulling out desirable directions. However, there are many hams that use them and are happy - if you can throw some of those nice gain lobes in a desirable directions, and not worry about those pesky nulls. An inverted L for the lower 3 band, 160-40, and a separate 25 ft vert for 40-10 is pretty straightforward, still needs a wide range tuner, but has no crazy lobes and is pretty good for DX on all bands. This is my personal choice. Of course, verts are a good S unit down from even a simple dipole (up 1/2 wave or more), which pretty means you won't have TheBigSignal on the upper bands, 20M and above, where almost anybody can put a dipole at a respectable height. Or, the inverted L for 160-40, and a separate multiband dipole at 35 ft heioght for 30-10. Both will give you a very nice low angle DX signal. So, IMHO, loops intended to cover all bands are generally not a good idea unless you are ok with the spotty directional performance on the medium and upper bands - there's almost certainly a better use for all that wire and those multiple supports :) |
