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Author Topic: Active Hula Hoop Loop Antenna  (Read 3639 times)

Offline ChrisSmolinski

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Active Hula Hoop Loop Antenna
« on: May 21, 2017, 2005 UTC »
A post about my active antenna made with two hula hoops:

http://www.radiohobbyist.org/blog/?p=2130


Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline Pigmeat

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Re: Active Hula Hoop Loop Antenna
« Reply #1 on: May 23, 2017, 0053 UTC »
Wayne Green would be proud of you, Chris. He loved those things.

BTW, the first time I saw an article on the horizontal loop you swear by was in "73 Magazine" entitled "What's The Scoop On The 'Lazy Loop'?" Wayne was decades ahead of his time in showing people how to piss off their neighbors with weird antennas.

Offline RobRich

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Re: Active Hula Hoop Loop Antenna
« Reply #2 on: May 23, 2017, 0333 UTC »
Liking the multi-way switchable amp design. :)
 
One possible tweak for later experimentation. Consider replacing the hulas with copper tubing, or maybe even just copper wiring. I suspect given the potential for increased resistive losses in an aluminum foil loop, a solid copper wire of a decently sized gauge placed inside each hula could work about as well (or better?), plus it also could allow for an improved electrical connection (and possibly less loss) between the antennas and amp versus the current mechanical feedpoint connections to foil.
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Offline ChrisSmolinski

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Re: Active Hula Hoop Loop Antenna
« Reply #3 on: May 23, 2017, 1151 UTC »
Liking the multi-way switchable amp design. :)
 
One possible tweak for later experimentation. Consider replacing the hulas with copper tubing, or maybe even just copper wiring. I suspect given the potential for increased resistive losses in an aluminum foil loop, a solid copper wire of a decently sized gauge placed inside each hula could work about as well (or better?), plus it also could allow for an improved electrical connection (and possibly less loss) between the antennas and amp versus the current mechanical feedpoint connections to foil.

Interesting idea. I went with the foil over the hula hoop to minimize inductance,  I'd have to look up the resistance of aluminum vs copper to see how much of a difference there is. Another possibility would be to use copper foil. Best of both worlds?
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline ChrisSmolinski

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Re: Active Hula Hoop Loop Antenna
« Reply #4 on: May 23, 2017, 1154 UTC »
Wayne Green would be proud of you, Chris. He loved those things.

BTW, the first time I saw an article on the horizontal loop you swear by was in "73 Magazine" entitled "What's The Scoop On The 'Lazy Loop'?" Wayne was decades ahead of his time in showing people how to piss off their neighbors with weird antennas.

The Sky Loop truly is King. It's the best overall performing antenna I have ever built. It plus the netSDR are a formidable pair of DXing tools. If I ever clear the brush in the back acre of the lot, I could probably double the area of the loop. I've only been meaning to do that for 20 years  ;D
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline redhat

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Re: Active Hula Hoop Loop Antenna
« Reply #5 on: May 23, 2017, 2149 UTC »
Exposed aluminum outside in the elements will develop aluminum oxide, an insulator, which may with time affect shielding and electrical performance.

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Offline ChrisSmolinski

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Re: Active Hula Hoop Loop Antenna
« Reply #6 on: May 23, 2017, 2223 UTC »
Exposed aluminum outside in the elements will develop aluminum oxide, an insulator, which may with time affect shielding and electrical performance.

+-RH

Thanks for the tip, I was actually thinking about that possible problem. I wonder if covering the foil with tape might help reduce that? OTOH, I've had aluminum antennas before (such as a VHF/UHF scanner antenna) that had aluminum elements, and was OK. The elements developed an aluminum oxide coating, but as long as the electrical connections were protected, it was fine. I do have tape over the wire to aluminum connections now.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline redhat

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Re: Active Hula Hoop Loop Antenna
« Reply #7 on: May 24, 2017, 0543 UTC »
if you use aluminum tubing that will work fine.  The problem with foil is you have a number of loose layers to retain water and promote oxidation.

+-RH
Somewhere under the stars...
WinRadio Excalibur/305 w/ a chi-town resonant loop, Kenwood KDC-U356 for mobile listening.
Please send QSL's and reception reports to xfmshortwave [at] gmail [d0t] com

Offline Josh

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Re: Active Hula Hoop Loop Antenna
« Reply #8 on: May 24, 2017, 1648 UTC »
I'm considering some copper pipe, flatten it, cut it with snips into two flat strips, then make me some superconducting smolinskiloops.
Conveniently located near Vincennes Indiana.

Offline Oliver

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Re: Active Hula Hoop Loop Antenna
« Reply #9 on: May 24, 2017, 1819 UTC »
Chris,
when I build my active loop I pulled some heat shrink tubing over the copper pipe.
So far it works great for me.
RX: Elad FDM-S2, Grundig Satellite 700 & Yaesu FRG-7
Ant.: HDLA 3 (Active Loop), EWE @ 270, ALA 100LN, MiniWhip
QTH: JO31 (Germany)

Please send eqsl to: oliverinusa[at]yahoo.de

Offline Josh

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Re: Active Hula Hoop Loop Antenna
« Reply #10 on: May 24, 2017, 1854 UTC »
Oliver, what amp are you employing with the loop if you don't mind saying. Been looking for simple yet high dynamic range amp designs for such loops.
Conveniently located near Vincennes Indiana.

Offline Oliver

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Re: Active Hula Hoop Loop Antenna
« Reply #11 on: May 25, 2017, 0703 UTC »
Hello Josh,
I use a HDLA 3. The electronic was purchased from Henry W. Mohr here in Germany. ( www.hwmohr.de ,
info@hwmohr.de )
As far as I know from Henry he is currently out of stock on these fine electronics. But he mentioned that he is planning to build some more in fall of this year.
There are four versions of the electronic.
The HDLA 3,6,9 &12, the numbers indicate the loop diameter in meters. All electronics come with a power inserter box and are housed in a IP65 housing.
Price tag is a round 160 without S&H.
If you are interested send him a email and ask him for the current stock / building status.

Some comparison of the HDLA with other antennas electronics was done by Fenu. ( http://www.fenu-radio.ch/index1.htm#Fenu-Loop-HDLA2-3 )

I hope I could answer your question.

« Last Edit: May 25, 2017, 0715 UTC by Oliver »
RX: Elad FDM-S2, Grundig Satellite 700 & Yaesu FRG-7
Ant.: HDLA 3 (Active Loop), EWE @ 270, ALA 100LN, MiniWhip
QTH: JO31 (Germany)

Please send eqsl to: oliverinusa[at]yahoo.de

Offline Josh

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Re: Active Hula Hoop Loop Antenna
« Reply #12 on: May 25, 2017, 1556 UTC »
Indeed and thanks Oliver.
Conveniently located near Vincennes Indiana.

Offline ChrisSmolinski

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Re: Active Hula Hoop Loop Antenna
« Reply #13 on: August 17, 2017, 1611 UTC »
A short update, since I have been using this antenna for a few months now.

It's connected to my NRD 545. It actually works pretty well as a wideband antenna, from MW through most of HF. Not bad on LW either.

I've used it in the evenings when the beverage and AFE822 were already recording DGPS, and it did a respectable job picking up SWBC stations, including US and Euro pirates. Not as good as the beverage or sky loop, but still not bad.

I just strolled through the expanded part of the MW band, and it picked up everything the sky loop could, with generally only slightly to moderately weaker signals. There is certainly some directionality, certain stations are significantly stronger (or only present) on one of the loops vs the other. I notice this throughout the MW band. In same cases both loops work equally as well, this is likely a case where they are both at a 45 degree angle with respect to the azimuth of that station. Unfortunately both loop signals are not sent back to the shack, otherwise that might allow for phasing.

So while I would not consider it a "DX Magnet", it is an excellent performer for the size. Certainly something I would recommend to someone without the space for a full sized antenna.  It's possible that it could be further improved with a better planned pair of loops, vs the hula hoops and aluminum foil I used.  ;D
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop