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
