Around a year ago (Spring 2022), I decided to attempt a Full Wave Horizontal Loop for 160 meters–and you would be right in thinking, that’s a lot of wire. I bought 550 feet of 14 gauge stranded THHN from the hardware store. I will say I’m glad I bought this before the escalation of prices and some stores putting it behind lock and key.
The wire I bought was in two spools. I am sure I could have bought 1000′ spool, which I’d eventually use, but that was a larger cost than I felt like spending at the time. I ended up buying a 500′ spool and a small 50′ spool and attaching them with a butt splice (waterproofed and knotted).
Here is the feed point. There is no balun in the PVC, only a connection to the SO-239. I actually had a commercial choke in there but took it out due to a faulty connection. If you look closely at the loops, you will notice a mix 31 torroid I tossed in there.
The cable you see is in fact 75 ohm coax with F-connectors. It is 100 feet of RG-11. I used this to transform the impedance of the feed point to 50 ohms. I intended to modify the RG-11 length for matching but to much surprise and happiness it worked out perfectly with a single 100 foot section used during testing. It runs into 50 ohm RG-400 after the polyphaser.
Check out the analyzer data below to see how well this worked out. While it is true that the RG-11 here is copper clad steel, not solid copper, I did not find the need to buy the much more expensive solid copper 75 ohm coax. Some studies I read showed the skin affect (or lack there of) at 160m was not noticeable at 100 feet. Whether true or not may depend on your setup.
Now let’s look at the data from the antenna analyzer (Rig Expert AA-650 Zoom) at the feed point. Before the RG-11, |Z| was 108.6 ohms at 1912 KHz.
Here is the same data after 100 feet of RG-11. Not too bad in my opinion and only a small touch up tune maybe at the band edges.
And finally, the data from inside the shack after the polyphaser and RG-400.
Some final notes. Clearly each setup will be different. I think I ended up with about 515 feet of wire. My setup varies in height as I used trees as supports over varying ground terrain. The height is around 45 feet at the feed point, but may only be 20 feet above the ground in some locations (my property has many rock outcrops changing the elevation). It’s four sided, but not a square or a rectangle. Maybe closer to a right trapezoid and fed in the corner, not a side. Most importantly, it WORKS and it is substantially quieter than my 270 foot Off Center Fed Dipole (OCFD).
Hope to hear you on 160m! The Top Band SSB net is on 1900 KHz M-F at 2030 EST Winter and 2100 EDT Summer: topics of discussion Monday through Thursday with open round table on Fridays. I also work FT8 on 1840 KHz USB often if you want an FM09 contact!
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