The AlexLoop Antenna and RaDAR

The AlexLoop Walkham is a magnetic loop antenna designed and sold by Alexandre Grimberg PY3AHD from Brazil. See AlexLoop.com on the web. There are many experimenters building their own mag loops but the Alexloop is one of only a very few commercially available mag loops. The AlexLoop implements a mag loop for the 40 through 10 meter bands. It packs into a small bag that comes with the purchase. I am able to pack mine into a backpack with my KX3 and external battery. This is perfect for Rapid Deployment Amateur Radio (RaDAR).

AlexLoop and KX3 at St. Andrews State Park during RaDAR event

The AlexLoop is commonly supported by a camera tripod about three feet off the ground. I also use a four foot pole with a spike. It is necessary to be near the loop to retune it manually when there is a frequency change. The AlexLoop is rated for 10 watts on CW and 20 watts on SSB.

A backyard setup on family visit

The AlexLoop is about three feet in diameter. The loop itself is coax. The coax loop hooks into a capacitor box at the bottom using PL-259 type connectors. The vertical support for the loop are three plastic tubes that join together. The coax is unhooked and coiled and the tubes are broken down to yield the small pack up size.

The AlexLoop in my LowePro Flipside 300 Backpack

The backpack ready for RaDAR ops.

The AlexLoop can be purchased directly from Brazil. It is also sold by US vendors. I bought mine from W4RT and I see it now on the GigaParts web site. The price is around $350 which can cause a pause. However, you must consider that you are getting a ready to use product that is the result of many years of experimenting. It is not too different in price from the popular Buddipole products.

Now with the preliminaries out of the way, lets highlight what makes the AlexLoop a great choice for portable operations.

Size: The deployed loop is small compared to full size half wave or quarter wave antennas. It is also smaller than the typical shortened dipole or vertical. Note, there is no counterpoise required.

Height: It is recommended to be deployed at three feet as a vertical loop. I have used mine on a coffee table with the tripod legs shortened. So forget about masts or trees for support. It also could be deployed horizontally from a balcony.

Multiband: The loop operates 7 through 30 MHz. That is pretty good. Changing bands is fast as it just requires adjusting the tuning capacitor.

Bandwidth: Narrow! This is the price you pay. It does require retuning when moving up and down the band or changing bands.

Tuner: Not required and I advise against it. You will need an SWR indicating device.

Efficiency: I am not the technical expert on loops. I have seen figures of 90% on 10 meters down to 5% on 40 meters. In any case don't think that the efficiency will keep you from making contacts even on 40 meters.

Performance: I find it impossible to compare directly any two antennas for performance. Likewise, making contacts has a lot to do with conditions and opportunity that someone wants to QSO with you. Given all that, I have success on almost every portable outing. I have had the full range of operating outcomes. I have answered CQs with no luck, I call a station and get and get a weak report but QSO for 30 minutes and then call another station and get a strong report. This can be all in the same outing. I have also called CQ with no luck and also called CQ and get an immediate reply. I have also held a frequency down for an hour. This includes CW and SSB.

My web site N4KGL.info documents many outings with the Alexloop. One outing yielded eighteen contacts on 20 meters and eight on 15 meters. This included F6HKA in France and V31JP in Belize on 15 meters. At lunch one day I worked South Africa on 10 meters. Of course, any indoor contact is satisfying and 40 meter contacts are awesome. Just envision that 40 meter dipole you did not put up.

I surprised my relatives by setting up on the coffee table 

The bottom line is that you are going to be able to operate in almost any portable situation. This includes indoors. I have operated from hotel rooms, hotel balconies, and also my relatives living room off their coffee table. I have a camera backpack that holds the KX3, AlexLoop, external battery and tripod strapped to the back of the pack.

I have to warn you that this antenna is not for everyone and your mileage may vary. A beginner may be frustrated with unsuccessful outings. There is luck involved and also experience to be gained in finding QSO opportunities. I think State QSO Party weekends are a good time to get broke in. Likewise, it is natural to have a mindset that you can't do so much with so little. Give the Alexloop a chance and you will be surprised.

AlexLoop Tuning:

STOP you do NOT need a tuner or analyzer.

First, Simply adjust the knob for the capacitor for maximum noise at the desired operating frequency. I find with the KX3 you may have to turn on the preamp to hear noise. For the KX3 take advantage of the S meter and tweak for a peak on the meter. You may be rewarded with being close enough. To complete the tuning produce a carrier (XMIT button on the KX3) and carefully adjust the knob for min SWR. You can get as low as 1.1 or 1.2. However if you get 1.5 to 1 a few KHz over it will be 1.1 to 1. On 10 meters the SWR does not get as low.

I don't have any financial interest in Alexloop, Other than I am a satisfied customer. I have really gotten my money's worth over and over. I really have to wonder why I should break out a larger antenna for portable ops. Also, Alex the ham is friendly and responsive. He participates in the KX3 and Mag Loop forums on Yahoo groups. Thanks Alex for a great product. Your efforts are appreciated.

KX3 and AlexLoop demo at the 2013 Orlando Hamcation

The Rapid Deployment Amateur radio (RaDAR) program is a good way to exercise your portable operating skills and equipment. The Alexloop is perfect for RaDAR. In RaDAR you might make a contact walk 1 kilometer and make another. This Alexloop fits that bill. See this link for the RaDAR Program rules. In addition, there is a Google+ Community for sharing your RaDAR operations at this link You don't have to join the community to participate in RaDAR. The RaDAR program is administered by Markus KD0JKM. The RaDAR concept was originated by Eddie ZS6BNE.

2013 Field Day (KX3 at 10 Watts and Battery Power)

I did Field Day with the Panama City ARC at the Bay County FL EOC this year. The club was operating 2F under the call W4RYZ. I was at the outside operating position. The setup included a Hex Beam and a 40 meter full wave loop. My first comment is that I enjoyed the time with my fellow operators out there. They included  Bob KK4DIV, Phil KK4DWI and Bob WB3DEH. I also want to thank the many club members for the help with setup and tear down

I had a goal to operate 100% battery and that was achieved. I used only 6 AH from a 15 AH Bioenno LiFe battery. So I could have done another Field Day easily on the same charge. I ran the lights off of a SLA battery.

The NA4RR Hex Beam was a easy setup. It seems to be about an hour for assembly and raising it to 18 feet on the mast. The pre-cut elements are awesome and the SWR comes out around 1.1 or 1.2 on every band. We did not have a rotator but we could tell it was directive. We snagged Hawaii on 15 meters. We also got Puerto Rico and Virgin Islands. A highlight was Sunday morning on 10 meters. We changed the operating mode to calling CQ instead of hunt and pounce. That started a string that must have been about 40 contacts. It was nice to be doing this with 10 watts. So perhaps the Hex Beam was a factor there.

The 40 meter full wave loop did well. We used it mostly on 40. We had to work for the contacts on 40 SSB but overnight we made a bunch. 40 CW was no problem.

My KX3 did a great job and everyone was impressed with the audio. It did a good job selling itself and it is now on Phil's wish list. I had a desk mike supported by a lamp and foot switch that worked out well.

The pond had more water this year and more frogs croaking. It was the biggest source of QRM that night. We were not sure how much of our outgoing audio was frogs.

My conclusion is the 10 watt Field Day was a success and was enjoyed by the ops. I don't have the logs in hand for the numbers. So we will have to analyze them later.

Bob KK4DIV operating

NA4RR Hex Beam

Easy up illuminated

Sunrise at the FD Site

The 40 meter full wave loop was deployed over a small pond. It is hard to see.

I could of had a V8!

I could be doing a RaDAR Field Day. Oh well, instead I am setting up a home station in the field. Silly me. My KX3 and Alexloop would do fine I think. However, have packed up almost all the gear I own including a Hex Beam. I'll be operating with the Panama City ARC. We will be W4RYZ 2F NFL. The site is the Bay County FL EOC North of Panama City, FL. RaDAR is Rapidly Deployable Amateur Radio. See this link for info. Everyone, Good luck at Field Day!

RaDAR in the Month of May

In the month of May, I kept a log of my Rapidly Deployable Amateur Radio (RaDAR) activity. RaDAR is a good way to exercise your portable operating skills and equipment. See http://radar-america.blogspot.com/ for the rules. I had 18 RaDAR outings (16 Portable, 1 Mobile, 1 Pedestrian Mobile) at ten locations with 42 QSOs total. In RaDAR there are portable, mobile, and pedestrian mobile categories. The categories are a little different from what you might think. So take a look at the rules.

My Mobile outing was  5 contacts at St. George State Park, 6 contacts at St George Lighthouse, 1 at a park in Apalachicola  FL for 336 points. My Pedestrian Mobile outing was a 2.5 km walk 5 contacts and a 2.5 km walk at TopSail Hill Preserve State Park FL for 192 points

I calculate 956 points total for May. The Mobile and Pedestrian Mobile categories get multipliers. Lots of bonuses in the rules. I am dismal at logging so the program inspired me to do better. There is a Google+ Community: Rapidly Deployable Amateur Radio (RaDAR) for sharing your RaDAR operations https://plus.google.com/u/0/communities/109283065808971118728 It is easy to post a picture of your setup using the smart phone. I am encouraging the community to make at least one RaDAR outing a month.

EM70OQ88 St. George State Park FL

E79NP69 St. George Island Lighthouse

EM79MR23 Park in Apalachicola FL

EM60UI Topsail Hill Preserve State Park near Miramar Beach FL

EM70CE82 Lunch Ops near La Quinta on Thomas Drive Panama City Beach FL

EM70ED45 Panama City ARC Club House

EM70DF90 Walking Park Panama City FL

EM71GF Parent's House Dothan, AL

EM70EL23 Mr. Grumpy's Crooked Fence Ranch South Port, FL

EM72NN Brother In Law's Yard Columbus GA

40 Meter Full Wave Loop for Field Day

As a complement to the Hex Beam as one Field Day antenna I decided on a 40 meter full wave loop as the second antenna. I can get it nearly 30 feet high with three 31 foot Jackite poles. The feet point is supported by fiberglass mast sections off a hitch mount on the truck. One motivation is that it is fairly compact as a diamond shape. It is about 36 feet on a side. That should fit the area available at our Field Day site.  I considered feeding it with balanced line but decided to use a 4 to 1 balun at the top of the mast. With this choice I did not get a 1 to 1 SWR but it has a good dip at 40 and the harmonics 20, 15 and 10 meters. For most of it, I could go without a tuner. The rest is easy range of the KX3 internal tuner. I cut it long of course and it was low in frequency. After three trims and much sweat it is just where I want it. The whole thing did fit in my front yard. I had one support at 20 instead of 31 feet because it was getting close to the power line drop for the house. I found the trimming for SWR very sane and was better than my experience with a 40 meter off center fed dipole I used last year.

They say it is NVIS on 40 and I can think of no better plan for Field Day. I hope to have both the hex beam and the loop on a coax switch. I did not try any QSOs as I needed to head out to lunch. I hope everyone can get a taste of Field Day this year. It is June 22/23.