Faraday Coupling Loop
Posted: Tue Oct 30, 2012 9:22 pm
A few questions on your coupling loop. I have built a few mag loops and researched most of what information I could find on them. Most of all that I have read uses a Faraday loop for coupling and it is mounted at the bottom, both of which were done for the maximum performance of the loop. I noticed that both you and Alex do not use a Faraday loop (just straight coax) and have the whole loop antenna inverted from the original designs which have the capacitor at the top and the coupling loop at the bottom. I understand the mechanical reasons for this inverted design, but is there a trade-off in performance?
Speaking of which, I think I saw in your video a vertical antenna in the background. Have you done a A/B test between it and your loop?
I built a loop (same diameter as yours) using 19mm (3/4 inch) copper tubing and had it outside up at about 6 meters for two years. During that time I also had a 15m dipole, a 90 foot Broad Band Folded Dipole, and a 44 foot doublet fed with 28 feet of 300 ohm twin lead to a Elecraft T1 remote tuner (not all up at the same time) at roughly the same height. Not too many times in the 2 years of A/B testing did I find the loop to be better than or equal to the other antennas on 20m - 10m. I should also say that before I started building the mag loops I did have a MFJ-1789 (Magnetic Loop) which I found performed pretty much the same as the ones I later built.
I also have a portable loop using 9913 coax and a Faraday coupling loop. While this loop does out perform small antennas such as my Miracle Whip, PAC-12, and HamSticks, this year for Field Day I also used a home made EFHW (End Fed Half Wave) with coupler on 20 meters and it noticeably out performed the loop. That being said, for a 1 meter tall antenna that only needs to be maybe 2 meters off the ground I would say that it's the best in that size and pretty hard to beat so maybe that is what makes it so popular.
So I guess my two questions would be: Have you compared the Faraday loop vs just a loop made from RG-58 (or heard any Pro/Con about the two), and have you compared your loop antenna A/B wise to any other antennas?
I loved your trees in your video by the way
73's
de George
WD0AKZ
Speaking of which, I think I saw in your video a vertical antenna in the background. Have you done a A/B test between it and your loop?
I built a loop (same diameter as yours) using 19mm (3/4 inch) copper tubing and had it outside up at about 6 meters for two years. During that time I also had a 15m dipole, a 90 foot Broad Band Folded Dipole, and a 44 foot doublet fed with 28 feet of 300 ohm twin lead to a Elecraft T1 remote tuner (not all up at the same time) at roughly the same height. Not too many times in the 2 years of A/B testing did I find the loop to be better than or equal to the other antennas on 20m - 10m. I should also say that before I started building the mag loops I did have a MFJ-1789 (Magnetic Loop) which I found performed pretty much the same as the ones I later built.
I also have a portable loop using 9913 coax and a Faraday coupling loop. While this loop does out perform small antennas such as my Miracle Whip, PAC-12, and HamSticks, this year for Field Day I also used a home made EFHW (End Fed Half Wave) with coupler on 20 meters and it noticeably out performed the loop. That being said, for a 1 meter tall antenna that only needs to be maybe 2 meters off the ground I would say that it's the best in that size and pretty hard to beat so maybe that is what makes it so popular.
So I guess my two questions would be: Have you compared the Faraday loop vs just a loop made from RG-58 (or heard any Pro/Con about the two), and have you compared your loop antenna A/B wise to any other antennas?
I loved your trees in your video by the way
73's
de George
WD0AKZ