Big Magnetic Loop for QRP in the Park

AA1IK Hagen's Cove Florida

I’ve been experimenting with magnetic loop antennas of various sizes and configurations for the past year or so. They are fun to build and even more fun to use.

QRP and Magnetic Loop antennas go hand in hand for many reasons. They work well, are very quick to set up, and are bidirectional! Its nice to be able to ‘aim’ an antenna at a prospective target, like say ‘Africa’!

Copper face plate with PL 259 and Gamma Match sticking out of the side

Gamma Match, Antenna Feed Box

Soldering with a plumbing torch is necessary in some places, like attaching the main loop tubing to the PL 259. 

It may not look very pretty here, but believe it or not, my torch soldering skill is actually improving. The PL 259 is attached with screws and is soldered with a regular soldering iron to reduce inter component resistance. I’ve pretty much settled on the Gamma Match for a number of reasons. It’s easy to match and its easy to build. It works well too.

This T’ fitting helps to make the loop more stable, therefore easier to transport for portable ops.

PVC Tee, Fitting Helps to Make This Antenna More Robust!

What would hams do without PVC pipe?

Half inch PVC tubing bisects the mast and passes through the center of it. This three point connection stabilizes the loop and makes it much more robust. My first few magnetic loops didn’t have this feature and were a bit ‘wobbly, and bent more easily as they bounced around in the back of my truck.

This is the ‘business end’ of the Gamma Match 

Gamma Match Connection is Soldered With a Pluming Torch 1

Using a plumbing torch, I attached this copper strip to the Gamma match from the main loop tubing.

Here is another nifty improvement 

Tuning Stick Keeper 2

You can see the support PVC pipe passing through the center of the mast here, The black piece is a plastic pipe clamp. It is held in place with tie wraps. I try to keep the use of anything made of metal to a minimum in the center of the loop.  I’m not worried about radiation patterns as much as trying to keep the overall weight  of the antenna low. The smaller PVC pipe on the left is a tuning stick. It is tied to the capacitor and is very light and makes reaching way up to tune the antenna unnecessary. Keep in mind that merely approaching this antenna closely affects the SWR. Touching it certainly changes the SWR as well.

How Well Does It Work?

The Compas Aids for Pointing the Antenna in the Right Direction

I got great signal reports today, and that is saying something for a high Q antenna and only 5 watts of RF

This is my favorite pavilion at Hagen’s Cove Florida.

My Favorite Pavilion at Hagen's Cove is 50 Feet From the Water

Hagen’s Cove is about 17 miles from my home, along the shore route. Its a county park that is right on the Gulf of Mexico. This particular pavilion is only 50 feet from the water’s edge. I bring a sandwich and bottle water lunch, but it took me an hour to eat it today. I had very curious visitors asking a million questions about radio, and my set up. I also keep my QSL cards handy to pass around. Visitors really like seeing them.

Hagen’s Cove

Hagen's Cove Florida, My Favorite QRP in the Park Venue

There is a kayak and canoe launching ramp here. Air boats have their own launch site close by. And darn it, I forgot my noise canceling headphones today, again! Air boats pass by in only inches of water and just 50 feet away, so I can’t hear anything on the radio when that happens. I have this place all to myself during the week, but its busier on weekend as you can imagine with such a nice venue.

For more information about Magnetic Loop Antennas go to http://groups.yahoo.com/group/MagneticLoopAntenna/

or http://groups.yahoo.com/group/MagLoop/

Hagen’s Cove is in Taylor County Florida http://taylorflorida.com/

73 de AA1IK

Ernest Gregoire

Ernest Gregoire, AA1IK, is a regular contributor to AmateurRadio.com and writes from Florida, USA. Contact him at [email protected].

7 Responses to “Big Magnetic Loop for QRP in the Park”

Leave a Comment


Subscribe FREE to AmateurRadio.com's
Amateur Radio Newsletter
News, Opinion, Giveaways & More!

 
We never share your e-mail address.

Also available via RSS feed and Twitter (@amatradio).


Subscribe FREE to AmateurRadio.com's
Amateur Radio Newsletter

 
We never share your e-mail address.

Ni4L Antennas
Associated Radio
Hip Ham Shirts
Austin Amateur Radio
West Mountain Radio
R&L Electronics
N3ZN Keys
DX Engineering
GigaParts
Aspect Solar
Win4K3 Suite
Georgia Copper
InnovAntennas/Force12
BuyTwoWayRadios
American Radio Supply
N4PY Software
KB3IFH QSL Cards
Ham Shirts

Do you like to write?
Interesting project to share?
Helpful tips and ideas for other hams?

Submit an article and we will review it for publication on AmateurRadio.com!