Re: Topband: 2 wl loop, worth the effort? (Rob Atkinson)
I put up an 1100 foot horizontal loop about 6 years ago here in Fort Collins, CO. out in the clear in my back field held up by four 70 foot utility poles spaced about 280 feet apart. Fed by about 220 feet of 450 ohm window line, back to a Palstar BT-1500A true balanced tuner. The loop wire is about 65 feet off the ground I also have a full size vertical for 80M and an inverted L for 160 over a bed of 55 radials 90 feet long fed with 200 feet LMR400. See my QRZ page. There are times when the loop is better or worse than the verticals for 80 or 160 but the comments I have heard seem to go (partially) against what I have experienced with my loop. One example: When FT5ZM was on the air, that DX-pedition is about as far away from my QTH as possible, yet I heard them for between 12-20 minutes every morning and worked them on 160M CW when they were FOUR S units out of the noise (on the 1100 foot loop), speaker copy, no headphones needed! The loop in this case was two S units better than my inverted L and quieter. So, take that as my real world (not computer modeled, not guessed at because I don't have one) experience. Is there some magic at my QTH? No, I don't think so. But as many details I could attend to were done correctly. Is the loop worth the effort? Only you can choose for yourself. My effort was quite a bit of work with huge and heavy utility poles, drilling big holes, putting in 1 ton of concrete per pole, the pulley system to raise and lower the corners, the numerous times I have repaired the feedline connection (we have lots of wind here, up to 100 mph) and all the little details that go along with it. Was it worth it for me? Heck yes. I use it on 160-30M and have verticals for each of those bands as well for when the signal angle and direction or multiple lobes of the loop better suits one antenna over another. 73, Dan W7RF On 12/2/2015 5:54 PM, topband-requ...@contesting.com wrote: 2 wl loop, worth the effort? (Rob Atkinson) _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Balun or no balun
Kirk, I put up a large horizontal loop and can use it just about everywhere but since I have a Yagi for 20-6M, the loop gets used primarily on 160-30M. The loop I put up is about 1100 feet of wire in a square up 65 feet (supported by four 70 foot utility poles I planted in my field) fed with about 220 feet of 450 ohm window line. The 1100 feet amount of wire was chosen more based on what I could fit but I wanted about 2 wavelengths on 160M. It works VERY well for DX on 80-40-30M and depending on wave angles, can work very well for DX on 160M. Stateside signals on 160-30M are very good as well. I worked FT5ZM on Amsterdam on 160M and I had a time window of about 20 minutes in my morning with signals up to 4 S units out of the noise, no headphones needed! There are many mechanical considerations when using a feedpoint that is not supported but floating (I use a pulley system to raise and lower each corner). I bring it back to the shack horizontally supported by PVC topped 10 foot TV mast. Then right where it enters my shack through a board pinched by the sliding window, I use RG-213 for about 5 feet to get through the wood and not to worry about unbalancing the parallel conductors as it is near metals in the window frame, etc. To do this, I use the center conductors of the coax as each leg of the feedline and ground the shields at the tuner but leave the shields open where it meets the 450 ohm feedline. I use simple banana plugs/jacks at that outside junction to quickly disconnect for lightning. I tune it with a Palstar BT-1500A true balanced line tuner. I hope this gives you some food for thought showing how one Ham did it. On 80M results are sometimes better, sometimes worse than my full size 80M vertical, depending on what DX I'm working. It has been said by many "once you put up a loop, you never take it down". If you are feeding it with 30 feet of 450 ohm window line that means it will not be up very high so I would expect your DX results would be limited on 160 and 80M. Undoubtedly there will be opinions but I can tell you that this configuration works incredibly well for me. 73, Dan W7RF www.radiodan.com Fort Collins, CO Message: 6 Date: Tue, 11 Nov 2014 04:46:56 GMT From: W3AW via Topband To:topband@contesting.com Subject: Topband: Balun or no balun Message-ID:<000f425e.05b960860e39f...@aol.com> Content-Type: text/plain; charset="utf-8" I have put up a 160 meter horizontal loop fed with 30 feet of 450 ohm feed line to my tuner. I have a Radioworks 4 to 1 balun. I am considering splicing into the feed line at 10 feet so I can run 20 feet of coax into the shack. Thoughts? I run a qrp plus on 160. Kirk W3AW Illinois -- 73, Dan W7RF www.radiodan.com _ Topband Reflector Archives - http://www.contesting.com/_topband
