Magnetic Loop Antennas

[The DB]

I know that hams use horizontal beams to take advantage of ground gain now, but was this something that was known to CBers 30+ years ago when the horizontal for DX recommendations were first made? I never heard anything about it back then.

Horizontal ground gain was known by hams in 1939 when they printed the first edition of the ARRL Antenna Book (only cost 50 cents back then, lucky them), and honestly, it was old news for ham's even at that point... Unfortunately I don't have any CB books that talk about this effect. That being said, the books I do have that talk about CB were geared for absolute beginners and would not have covered such a topic.

Early 90's there were CB operators around that knew of the ground effects of horizontal antennas, at least here in St. Louis. That is about when I got started. Was it general knowledge that every CB operator knew? No as most used CB only in the mobile, but it was known if you hung around in the right circles, generally the ones that included older operators, and that was 25 years ago. It just so happens that many of those right circles are easier to access via tools such as forums today...


The DB

 

[Captain Kilowatt]

I know that hams use horizontal beams to take advantage of ground gain now, but was this something that was known to CBers 30+ years ago when the horizontal for DX recommendations were first made? I never heard anything about it back then.

I got started in 1977 when I was 14 years old. Already by then I had been reading ham magazines and such learning about antennas and propagation.By the time I was 16, which would be 1979 I had my own copies of the ARRL Handbook and the ARRL Antenna book as well as more from the ARRL and the RSGB. I knew about ground gain at least that far back. It was not something that was unknown but rather something that you had to learn about and do so from the right source and not from Billy Bob's CB Shop and Steakhouse.

 

[StrangeBrew]

I guess I have some catching up to do.

 

[Riverman]

Okay, group. Two more questions:

1. Since most magnetic loops are handheld or mounted on short tripods and thus close to the ground, what kind of take-off angle do they have? Or does it matter?

2. Is a wire dipole in an attic in close proximity to house wiring, an AC/Heating Unit, foil covered ducting, metal vents and a boatload of stored items hooked to 65' of coax going to be drastically better than a small magnetic loop antenna set up on my patio using 6' of coax?

 

[Captain Kilowatt]

Okay, group. Two more questions:

1. Since most magnetic loops are handheld or mounted on short tripods and thus close to the ground, what kind of take-off angle do they have? Or does it matter?

2. Is a wire dipole in an attic in close proximity to house wiring, an AC/Heating Unit, foil covered ducting, metal vents and a boatload of stored items hooked to 65' of coax going to be drastically better than a small magnetic loop antenna set up on my patio using 6' of coax?

The following is a quote from the link I posted a few posts ago. It was about half way down the page.

"However the small loop has one very significant advantage over any other antenna due to
its unique radiation pattern. If the vertically oriented loop’s figure-8 doughnut pattern
radiation lobe is visualised standing on the ground the maximum gain occurs at both low
and high angles, radiating equally well at all elevation angles in the plane of the loop, i.e.
radiation occurs at all vertical angles from the horizon to the zenith. Because the loop
radiates at both low and high angles, a single loop can replace both a horizontal dipole and
a Vertical. This is particularly beneficial on 160, 80 and 40m where the loop will provide
outstanding local / regional coverage and easily match and often outperform a tall ¼ λ
Vertical for long haul DX contacts, i.e. an exceptionally good general purpose antenna."

 

[Riverman]

Thanks, Captain. My memory simply isn't what it used to be.