If it is a horizontal loop it better be pretty high or else all your signals are going to heat the clouds and worms. try an inverted L or some type of shortened dipole of V if you need to be on 160.
Mike W0MU J6/W0MU November 21 - December 1 2011 CQ WW DX CW W0MU-1 CC Cluster w0mu.net On 10/15/2011 4:00 PM, gold...@charter.net wrote: > Based on all my research today it is apparent that the loop as put up > will have to come down. > > As Don points out, I dont want to be in the middle of the microwave. I > just never thought about this other than the nice layout of trees. > > Basically I will be pulling it down and use some of my trees and then > have to put two poles up for two corners. > > Plus it is clear since I want to use it on multiple bands that I will > have to get a 4:1 current balun. > > At least the radio warned me that I was making a microwave by all the RF > in the shack. > > I am not as smart on this stuff as I thought I was, as I did research on > the loop and length and so on, but never figured the effect on being in > the middle. > > But my dipole works just fine and I will continue to be on the air. > > Thanks > Don > > > ~73 > Don > KD8NNU > > > On Sat, Oct 15, 2011 at 2:41 PM, Don Wilhelm wrote: > >> Since the loop surrounds your house, you have put the house (and >> shack) directly into the highest RF Field for that antenna. >> >> If your house provides good shielding - metal roof and a metal mesh >> shield for the siding, with every piece of metal bonded together, you >> are going to have a lot of direct RF in the shack just from the >> antenna field. >> >> How much power are you attempting to run. You may get away with QRP >> levels, but at higher power, you should expect problems. >> >> I suggest first doing an RF Emissions Safety study to determine just >> how much radiation you are getting at the house location, and protect >> yourself and your family as a first order of business. >> If you cannot move the antenna to another location, perhaps you can >> get it higher which might help a bit. >> >> I just looked at one of L B Cebik (SK) modeling studies for a 1 >> wavelength diameter horizontal loop, and if it is 0.15 wavelength >> above the ground (80 feet at 160 meters) the radiation is a maximum at >> 52 degrees from the plane of the loop. At lesser heights, the maximum >> radiation will be closer to perpendicular to the plane of the loop. >> That does place your shack directly in a high RF Field. >> >> 73, >> Don W3FPR >> >> >> >> On 10/15/2011 12:14 PM, gold...@charter.net wrote: >>> I set up a 160m loop in the yard to try one out from all the great >>> reading I did regarding the antenna. >>> >>> For me I can get it to tune with no problems except the RF in the >>> shack >>> is terrible. >>> >>> I ran 450 ohm ladder line from the antenna to my balanced line >>> connections on my MFJ 962 d tuner. >>> >>> As soon as I connect the ladder line the RF is bad, basically >>> everyone >>> states that I sound like I am in a jet airplane. >>> >>> Now there is also a bit more to the story as the loop surrounds the >>> house as that is how the trees are plus the dipole is also very close >>> to >>> one of the edges on the inside of the loop. >>> >>> So I dont know if the problem is that everything is in the middle of >>> the >>> loop, or running ladder line into the shack is a bad thing, maybe the >>> tuner internal balun is not the correct one. >>> >>> Bottom line is the K3 was real unhappy with this scenario so the >>> ladder >>> line is pulled out of the shack and coiled up on the tree next to the >>> loop outside. >>> >>> One thing I have researched this morning is that I need a current >>> balun >>> and I should have it external to the shack and run coax between it >>> and >>> the shack. Also I should have the shield grounded like I do with the >>> dipole to direct ground. >>> >>> So I thought I would share my current failure while I ponder my next >>> move or give up on the loop. Ok I wont give up, YET! >>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
