By Jock Elliott, KB2GOM
It’s humorous how one can begin out desirous about the right way to clear up an issue, the entire course of takes a flip, and also you wind up with an surprising however pleasing consequence.
It began innocently sufficient. Alan posted this — https://swling.com/weblog/2024/11/bbc-rd-how-to-test-a-loop-antenna/ — and this assertion appeared on the finish of a BBC report on the right way to take a look at loop antennas:
“Polarisation Illustrations of the antenna often present it mounted upright; that’s, with
its axis parallel to the bottom. That is effective for the reception of LF and MF transmissions, that are vertically polarised, however most HF transmissions are horizontally polarised.”
After I examined that assertion right here — https://swling.com/weblog/2024/12/here-we-go-loop-de-loop-in-which-your-humble-correspondent-tests-a-hypothesis/ — there have been a few attention-grabbing responses.
Bob Colegrove mentioned (partly):
“To handle your conundrum, from my long-standing, untutored tinkering with loop antennas, I’ve concluded that, no matter LW, MW, or SW, optimum efficiency for peaks and nulls requires that the axis of the loop (i.e., line via the middle of the coil) be capable to rotate 360 levels laterally and 90 levels vertically.” (emphasis mine)
Robert Gulley added:
“I must concur with Bob – if I could state it one other method, there isn’t any “correct” place for a loop when getting shortwave indicators.”
To which I responded:
“I suppose the last word setup is perhaps an articulated motorized out of doors mount with a joystick inside that may enable me to fiddle the loop to the optimum place.”
Early within the morning I awoke desirous about how a system able to manipulating my three-foot-diameter MFJ 1886 loop each vertically and horizontally is perhaps carried out. The whole lot that got here to thoughts appeared awkward, onerous to place collectively, tough to function, costly, and simply plain clunky.
I dozed off and awakened considering: “What a couple of actually small loop? I might maintain it in my hand and simply flip it to completely different positions to optimize reception, no tools required.”
A thought got here to thoughts: “You’ve bought a small loop antenna, why don’t you see what you are able to do with it?”
At this level, I have to make my Shameful Admission: I bought so intrigued by the thought of utilizing my wrist and hand to show a small loop to numerous orientations that I forgot that I used to be attempting to unravel the issue of manipulating a shortwave loop.
The loop that got here to thoughts is the Terk AM Benefit. I examined it right here. Designed to spice up indicators on medium wave, it’s a nine-inch tunable loop encased in plastic that requires no energy provide. It inductively {couples} with the ferrite antenna inside a conveyable radio. However I appeared to recall that it additionally comes with a direct wire connector that can be utilized with some radios. Maybe I might join it to my CCrane EP-PRO which has clips and a swap for an exterior medium wave antenna on the again of the case.
I discovered the Terk AM Benefit simply sufficient, however the direct wire connector required a serious archeological dig. As soon as I unearthed it, I plugged the connector into the again of the Terk AM Benefit, slipped the wires from the connector into the clips on the again of the EP-PRO.
Now to attempt it out . . .
Tuning slowly down the dial, I discovered throughout a really faint sign that I might barely copy. Reaching across the again of the EP-PRO, I switched from the EP-PRO’s inside antenna to the Terk AM Benefit exterior loop antenna (which I used to be holding in my hand), rotated it backward and forward, tipped it forwards and backwards, and – tah-dah! – was rewarded by a much more copyable sign. It was WEEU in Studying PA, 200 miles away, transmitting 6,000 watts into the darkness on 830 kHz. Switching again to the EP-PRO’s inside antenna, I attempted rotating the EP-PRO to optimize the sign however couldn’t produce a sign that was pretty much as good because the exterior loop.
Repeating the process with extra faint stations, I bought the identical outcomes: higher reception with the hand held loop antenna, and it was enjoyable and simple to make use of. I held it in my left hand (it’s gentle) so I might rotate the dial that peaks the sign with my thumb and dealing the tuning knob on the EP-PRO with my proper hand. It was a really pleasing, virtually addictive, expertise.
Should you’re in search of a potent setup for medium wave DXing, I can suggest the EP-PRO/Terk AM Benefit combo, regardless that it wasn’t my authentic goal. Name it serendipity.
Within the meantime, does anybody know what is perhaps the smallest loop that may very well be handheld for shortwave reception and would supply a efficiency enhance over a whip antenna?
