skywire

Skywire, Cloud Burner, Horizontal Loop Antenna

My current and favorite HF antenna is a 565' Horizontal Loop. I have done a lot of antennas over the years for HAM's and all of the wire antennas I ever did, were always the best! While, verticals have their place and performance for different scenarios, I was seeking one antenna to cover all the HF bands from 160 - 6 meters. To my surprise, the horizontal loop will also do, other bands.

I will add more information here soon but, I did want to add some screen shots from the mini600 antenna analyzer.

Current configuration is a rectangle. The loop was tossed over trees and makes direct contact with the trees. Most of the wire is at 40 - 60 feet and is at 20 feet at the lowest point. It is one continuous wire that is tied together to 450 ohm ladder line. The ladder line is 69' 6" to a, 4:1 current balun. From the balun, 7' 5" of RG-8X, runs into the shack. The coax is feeding into an MFJ-989D Versa Tuner V without the internal balun being used.

One thing, I always seek to do when, I do wire antennas is, to try and get all the bands, flat lined! If you look at the analyzer screen shots below, take note of how the SWR scans appear. I want the lines to be straight across the screen as it looks in the 17 meter band. When the SWR scan is flat lined on the band, I only have to set the antenna tuner once for that band. If, the band is not flat lined such as, the 80 or 40 meter bands, re-tuning will be required when moving, i.e., from the low end of the band to the high end of the band. However, if the SWR deviation is not extreme, not re-tuning will only have a slight off set in SWR. Re-tuning is always best though, so, the impedance (X) and the reactance (Z) both, capacitive ( X_C ) and Inductive ( X_L ), stay in check.

Z = R + jX

Where Z is the complex impedance. The real part R represents resistance, while the imaginary part X represents reactance. Resistance is always positive, while reactance can be either positive or negative. Resistance in a circuit dissipates power as heat, while reactance stores energy in the form of an electric or magnetic field. The best you can hope for is Z: 50.0 + 0.0j and SWR 1.0. MCL = (Maximum coupling loss). More information on reactance can be found here.

See the photos below of the performance of the loop without the tuner in line. 15 meters is, the best band of all the HF bands and the internal tuner of the radio can easily handle the band without a major reduction in power. The worst band of the HF bands is, the 160 meter band which, at it's lowest point has an SWR of 3.8 and rises to, just above 4 but, the MFJ-989D antenna tuner easily brings it in line. Z0=50, is the calibration on this analyzer since, 50 ohm RG-8X is, the first run out of the shack.