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, [email protected] 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:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
