| KD5KC |
Rating:  |
2014-06-13 | |
| Unbeatable for PORTABLE operations. |
Time Owned: more than 12 months. |
Right from the start, let’s be clear on something. I operate a lot of HF portable. I manage the W5-SOTA association, and I operate from many mountaintop locations. My LoTW profile has over 50 QTH locations entered in it. A look at my QRZ profile will give you the idea. After much experimentation, I had settled on the 88 foot doublet as my primary portable antenna. It was big, the 31 foot mast was over 5 pounds, and it took 15 to 20 minutes to set up, usually requiring a helper. But it did work well.
Frankly, I had seen the Alex-Loop antenna advertized a few times, and my thought was “Snake Oil”. How can a 3 foot diameter antenna possibly function well across 40m through 10m? I wasn’t willing to risk the price of the Alex Loop only to find out it was a gimmick.
In May of 2011 I was pondering a problem. I was going to Germany for 3 weeks and I needed a small antenna. I had lived in Germany for 8 years as a soldier, and I had many ham radio friends there. It was imperative that I get on the air with them for my visit. I had a Yaesu FT-817 portable radio, but I had no idea of how to get my 88 foot doublet and 31 foot Jackite Pole to pack small enough to carry on an overseas flight.
A week before the flight I still had no idea for the antenna. I was getting desperate. This was when an Alex-Loop Walk-Ham fell in to my lap.
With just a few days to go it arrived in the mail. The Alex-Loop Walk-Ham antenna came in a nice padded carry bag, and the total weight was just less than 3 pounds. The small size and weight would be easy to pack. In fact, it fit inside the backpack I used for my carry-on, and my entire portable station would fit in that back-pack.
After unpacking it, I read through the directions quickly, and set it up for a test. I stuck it up in a camera tripod on my patio. The antenna was about 4 feet off the ground. I only had time to make 4 QSOs on it before packing to leave. It was a very hot West Texas afternoon in early June. The first two QSOs were on 20m, and were at a range of about 1200 miles. The reports were promising. Not S-9+, but fully readable with 5-watts SSB from my FT-817.
I quickly tuned to 40m. Now, 40m on a hot West Texas summer afternoon isn’t the best band. The D-layer is active, and absorption is high. I wasn’t expecting much. But I heard two guys talking, so I broke in. They replied, and I had 2 nice contacts 400 miles away in Arizona. Again, this was with the FT-817 at 5-watts SSB. Surprising, to say the least. So I said a quick prayer, packed the Alex Loop with the rest of my gear, and got ready to fly to Germany.
That was 3 years ago. In that time, the Alex-Loop has become my #1 portable antenna. I have over 3000 portable QSOs on it now. The compact size has allowed me to operate portable from places where my doublet or even a buddi-pole with wire radials would have been impossible.
From the W5 region, using the FT-817 at 5-watts SSB or CW, I have worked into Alaska, Argentina, Australia, Brazil, Canada, Costa Rica, Cuba, Czech Republic, Eastern Kiribati (T32C), England, European Russia, Germany, Hawaii, Hungary, Italy, Japan, Luxembourg, Martinique, Mexico, New Zealand, Panama, Portugal, Puerto Rico, Slovenia, Spain, Virgin Islands, Venezuela and Wales.
From Central Europe, again using the FT-817 at 5-watts SSB or CW, I have worked Asiatic Russia, Austria, Belarus, Belgium, Bosnia-Herzegovina, Bulgaria, Canada, Canary Island, Czech republic, Denmark, England, Estonia, European Russia, Germany, Finland, France, Greece, Hungary, Ireland, Italy, Jersey, Netherlands, Northern Ireland, Poland, Portugal, Romania, Sardinia, Scotland, Serbia, Slovak Republic, Slovenia, Spain, Switzerland, Ukraine, United States and Wales. IT just works!
I have even been successful using it inside motel rooms, as long as it was near a large window.
About the antenna….
Alex Grimberg – PY1AHD is the builder of the Alex-Loop. His web site http://www.alexloop.com/ is full of information and ideas, and Alex is easy to talk to via E-mail. Alex is more than ready to help you build your own loop. He will answer questions and give suggestions to help anyone successfully roll their own.
The Alex Loop itself is made up of PVC pipe, coax, a variable capacitor, and assorted wire and other hardware. Someone with a good junk box could build one easily for a few $$$$. There is nothing magic or secret about it, and many have built their own.
Assembling the loop is as easy as slipping PVC pipe together, screwing in pl-259 connectors, and turning a knob. My portable station goes from back-pack to calling CQ in under five minutes. Packing it up to leave is just as quick. Tuning portable antennas (especially loaded verticals) can be a challenge, but the Alex-Loop will QSY from band to band in fifteen seconds or less. When properly tuned, I have never seen the SWR exceed 1.5:1 on any band. Best of all, there are no small pieces to lose.
Because the antenna has a high current when at resonance, it is imperative that the connections be clean and tight, or losses will kill the efficiency. This is why Alex uses gold-plated connectors, a nice touch. But you still must be certain the connections are clean and tight.
The Magnetic Loop antenna is a High-Q device. Getting it tuned properly to function is an absolute must. Trying to use it off-resonance will just end in frustration. Using an external tuner is just another exercise in frustration. Forget using a tuner, just get the loop tuned right and use it.
Being such a High-Q antenna has advantages and disadvantages.
The disadvantage is that the antenna tuning is critical, and you must constantly watch to see you stay in resonance. If you QSY, check it. It only takes a few seconds to re-tune. On the 10m, 12m, 15m and 17m bands, the loop is very easy to tune and a small QSY +/- a few KHz is not a problem. On 20m the tuning is a little more critical. On 30m the tuning is very tight, and on 40m I would call it “touchy”. Getting a good match on 40m takes a steady hand, and a QSY of 10 KHz will certainly require a re-tune.
The advantages of a High-Q antenna are that being so narrow banded, it does a very good job at rejecting out of band signals. I have often worked on a summit with two or three other portable operators. The High-Q of the Alex-Loop has allowed me to even share a band if I stayed at one end and they stayed at the other end, and we were only 30 yards apart. Try that with your random wires or verticals.
Another advantage of the loop is the radiation pattern. The loop exhibits a very broad radiation pattern in a figure-8 shape, with two sharp nulls. Often I have used these hulls to help block QRM coming from another direction while working others in crowded bands.
Although the Alex-Loop can be hand-held, and even tuned while holding it in your hand, after a while it does tend to get heavy. I have adapted a few tripods for working with the Alex-Loop. I have also from time to time stuck it on a Yucca Stalk, or a piece of PVC pipe tied to my camp chair.
If you are looking for a small, light-weight, multi-band compact portable antenna that is easy to set up, easy to use, and works well….. this one is for you. I see it has an average rating of 4.9. That says a lot.
Comparing the Alex-Loop Walk-Ham to the MFJ loop is just ridiculous. Of course a larger diameter loop with more skin effect will be more efficient. And also more difficult to fit in your backpack. Try putting the MFJ loop in your pack! A very unfair comparison indeed. Anyone who says they had trouble with the Alex Loop just didn’t know what they were doing, or has an ax to grind.
More recently the copy-cat ALPHA LOOP has appeared on the market. I had an opportunity to look one over. The main loop is made of several sections that need to be bolted together to form the loop. More connections just means more opportunity to have a poor connection, as aluminum does oxidize. Furthermore, stripping, losing or breaking a bolt or nut could put the whole operation at risk unless you carry spare nuts and bolts. Finally, the Alpha Loop web page is mis-leading. The Alpha Loop can be configured to work 40m through 15m, or 30m through 10m, but not 40m through 10m continuously tuned like the Alex Loop. You only learn this after reading the assembly manual. Since the prices are nearly identical, you decide.
Since I started using my Alex Loop 3 years ago, at least a dozen have been purchased by friends and SOTA operators. Not a single report of “RF burns” from anyone. And a quick check with a multimeter will show you that indeed the center and shield of the coax connector ARE SHORTED. You just need to use your multimeter to see that.
The Alex Loop Walk-Ham is a mighty fine antenna, allowing the portable ham to operate in places a wire or vertical with radials will not fit. It tunes continuously from 40m through 10m, and assembles quickly with no small parts to lose or break. If you want to build your own, contact Alex. He will help you along. But if you do not have the time, or the parts, or the skills…. or for whatever reason, the Alex-Loop Walk-Ham antenna isn’t Snake Oil. It works, and works quite well for portable operating.
If you are still unsure, trust me…. Take the chance on it. If you are truly unhappy with it, you will have no problem selling it used for only a few $$$$ less than you paid for it.
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| KC0PUZ |
Rating: |
2014-06-12 | |
| RF burns and light construction |
Time Owned: 3 to 6 months. |
The AlexLoop provides good signal reports and as the Rating category of "2" on eHam states the Alex Loop "Needs help". The first step in tuning this loop is to listen for the loudest RF from the audio. To attain the lowest SWR, you must transmit and turn the knob at the high voltage point on this antenna. I've been watching a friend use this antenna since Christmas, and while observing him tune the loop while transmitting with minimal power, he received RF burns on two different occasions.
Did you see that metal shaft coming directly out of the center and connecting with metal gears to the knob you grab hold of, which by the way has a metal tap screw that carries the power that will give an RF Burn? The more I look at this image, I then realize the variable air capacitor is ganged in series. Does this lower the efficiency of the variable air capacitor? Also, see that little metal bracket in the bottom left side of the matching box in the shape of a C? That comes from the ground side of the capacitor, which then encompasses the shaft. Does this couple the inductance of the capacitor?
Then I realized that the Alex Loop doesn't even bond the feed points of their antenna to the outer shield of the antenna! What in the world is going in here? Only the inner coax and not the coaxial braid is being used for the actual physical connection of the loop? Surely this can't be! Does this mean the wire used as the active element is shielded from performing as well as many of the competitors whose active tuning elements are fully exposed (ref. MFJ Loop and the Alpha Loop)?
Just saying, the Alex Loop seems to work, but everyone should be aware of any products short-comings before buying it. So, while I'm on this subject...the Alex Loop uses a very cheap black plastic box where the MFJ plastic is a little better, though the Alpha Loop plastic is an outdoor UL rated high voltage enclosure.
As far as RF burns coming from the MFJ loop, you remote tune it, so it ain't going to happen. The closest thing to the AlexLoop seems to be the Alpha Loop and they use a nylon shaft between the knob you touch and their capacitor. Also, both MFJ and Alpha seem to agree that a single variable air capacitor that isn't ganged in series is the proper physical design. |
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| KD8OPI |
Rating: |
2014-05-18 | |
| Its awesome. Believe it! |
Time Owned: 0 to 3 months. |
It looks like it can't work. Its isn't big, there aren't any coils, it doesn't weigh much, there isn't a fancy website, a 300 page book on how to use it, or hundreds of dollars of accessories. You don't put it up very high, there aren't any guy wires, and there is no microchip. The man who builds it doesn't have a team of people with him at Hamvention; just someone who appears to be his wife. He doesn't even have his own booth. What he does have though, is a write up in QST and 49 reviews on this site that say his antenna is great. Make that 50 now.
I bought this gem at Hamvention 2014 two days ago and put it up this evening after it stopped raining for the first time in 5 days here in Dayton. I spent a whopping $2.50 or so in materials to build the AD5X camera tripod mount (its functional). I take the AlexLoop on my deck, it takes <5 minutes to assemble and stick it on the tripod its about 4 feet off the deck, 8 feet off the ground.
Moment of truth. I turn on the 817nd, and tune the antenna. Nothing to it. Peak the receive, fine tune the SWR on xmit (I get no SWR on the "meter" on the 817), it takes 30 seconds with about 20 khz of bandwidth around the tuned frequency with no readable SWR.
Boom. Here come the signals. I can spin the mount easily with one hand from my lounge chair. Ah direction! I hear a Puerto Rician station starting to call CQ on 15 M SSB. I spin the plane of the loop SE/NW. I answer. QSO made, 5/3 me, 5/5 him. Yup, almost 2000 miles, my first contact with the AlexLoop. I tune up, hear a Japan station coming in nicely. I answer, no QSO - but hey come on there's only so much 5 watts and a loop can do! I mosey down to 20M and break through two odd pile ups in Mississippi and and in South Dakota. I pack it in, Game of Thrones is coming on, but I'm in awe of this marvel.
I own the Buddipole, and I have an S9 31' vertical with 32 radials, and I have an Alpha-Delta 5 band fan dipole. The AlexLoop is just easier, lighter, and dare I say better than all of these options I have from my deck when I want to play on the radio in the summertime.
Comparison to the Buddipole is most appropriate. The Buddipole does not suck , it is a solid antenna. But, its shortcomings are that it is much more difficult to set up and tune than the AlexLoop, with similar results at QRP power levels. I gave up tuning the Buddipole a long time ago with the coils, and used a tuner with it. I've also spent a pretty penny replacing telescoping elements on the B-pole, because I had it up 15 feet and it fell or my guy wire didnt got pulled out of the ground. When would I use the Buddipole now that I have the AlexLoop? If I ever go on a DX pedition, and have a day to set up guy a tripod mast and want to run >20 watts. Or if I want to build the 10M 2 element Yagi. I won't use it for QRP fun, there is no need. Forget about a Buddystick config or my S9 31' vertical, the AlexLoop has them beat - you cant beat the ability to peak and null with the direction the AlexLoop gives you compared with verticals.
Listen, if you want to have fun with a small, directional, effective antenna that is a snap to tune which you can mount on a simple camera tripod get this one. It really works, and works very well. Looks can be deceiving.
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| PA3CWQ |
Rating: |
2014-05-17 | |
| 5/5 |
Time Owned: 6 to 12 months. |
| It gives me a lot of fun working QRP in digital mode like JT65HF during my Holiday’s and also from my QTH of course. In May I was in Spain near Moraira Costa Blanca in JM08BR. I am always traveling with my qrp-rig, the Yeasu FT-817 (with a little accu) and my Alex loop. This loop gives me a lot of fun, only a little bag in my suitcase and I am qrv from 10 to 40 meter. I was calling cq on 14.076 MHz with 5 watt and John VK7XX was coming back for me. That gives me a lot of fun. |
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| AD0DQ |
Rating: |
2014-05-15 | |
| Best Portable Antenna |
Time Owned: 6 to 12 months. |
| I bought this unit without recognizing that it has a 25 watt power output limitation. When I discovered I was limited to 25 watts out, I was really upset about that (but that was my fault, not AlexLoop). But we had a special event (W0O -- Frankenstein MO) and I took my Alex Loop and worked PSK from Frankenstein, MO. I set the unit out in the yard, ran 25 feet of RG58U to it, tuned it with an MFJ259, and went to work on 20 meters. I made dozens of contacts on 20 meters from Florida to Seattle with band conditions that were less than optimum. I did that on 25 watts, and felt like I had better performance from the loop than I would likely have had from a dipole or some other temporary or portable 20 meter antenna. I would recommend this antenna for anyone who needs a portable and functional QRP antenna, with the understanding that you need to stay below 25 watts. |
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| K7RNO |
Rating: |
2013-11-24 | |
| A gem of a portable antenna! |
Time Owned: 0 to 3 months. |
Below are tons of reviews with QSO reports, so I'll spare you with that.
What I feel the need to address are these points:
1. Even if your rig has an ATU built in, resist the temptation to use it. You would do yourself a disservice. Your ATU will not and cannot tune the actual loop. You must tune the loop with its integrated tuner or you will leave power on the table! I put my ATU on bypass.
2. To get a solid mount, you want to have a base with the proper outer diameter to JUST fit inside the black pipe. The super lightweight (i.e., super flimsy!) Vivitar tripod's center column is too thin and needs an adapter that you can build with something in your junk box. Be creative, and duct tape is only one solution.
For better support, consider a heavier (i.e., more stable) tripod with a thicker column that might just fit out of the box. But for hiking, that light Vivitar thingie is hard to beat.
3. To speed up tuning from band to band even more, I use a modified knob with a 360° scale, which I calibrated to know the values for the individual bands. In my case, particularly the 17m sweet spot is often nearly impossible to hear, so calibration helps a lot. I posted an image here:
http://groups.yahoo.com/neo/groups/KX3/photos/albums/292559262/lightbox/173537466
The +/- column on my labels shows the bandwidth in kHz above and below the tuned f that I found doesn’t require retuning.
4. Follow Alex's recommendation to fine-tune the loop with just your fingertips. This way you avoid your fingers influencing the capacitor and detuning it some when you withdraw your hand.
5. This antenna is a blast! There will always be more efficient and less compromised ones, but none of those are as quickly set up and as versatile. Well done, Alex!
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| ON6KE |
Rating: |
2013-11-22 | |
| I must be MAD! |
Time Owned: 0 to 3 months. |
Hi everyone,
I must be MAD, totally bunkers, gaga, I ordered a Walkham loop this morning, 385 US$ shipping included, PLUS 21% if Belgian customs sees fit to add tax to it!
I sure hope the loop works extremely well.
By the way did anyone notice that there are 2 language errors on the English version of the tuning unit?
'recIEve' and 'trasmit'. |
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| KJ4FUU |
Rating: |
2013-11-13 | |
| Works even better than expected |
Time Owned: 0 to 3 months. |
This antenna is easy to set up and take down, and gives me a little bit of directional capability also. I've taken it out to the back yard for a couple of weekends, and had some success reaching some state QSO parties and special event stations.
My first time out the takedown speed became a major plus, because it started to rain. I quickly disconnected the radio and put it in the waterproof box. The Alexloop easily came down within 5 minutes, giving me time to haul everything inside before it started pouring down hard.
Tuning, even without an antenna analyzer, is simple.
I would recommend the Alexloop to anyone who likes to operate portable, or is restricted by the HOA from putting up a full-sized antenna. |
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| WW4MSK |
Rating: |
2013-11-06 | |
| Great QRP portable antenna |
Time Owned: 0 to 3 months. |
I've been using with decent success end fed wire antennas for portable and maritime mobile QRP with my KX3. In my search for another type of antenna to use, I came across various YouTube videos of people using magnetic loop antennas. It seemed to fit what I needed, something lightweight, easy to deploy/takedown and work on most bands I use.
From order to delivery took a little more than a week from Brazil to the USA. Alex provided a tracking number and once clearing US customs arrived nicely packaged. I had my radio ready to go on the deck outside, and from unboxing to first contact was less than 5 minutes. Not bad for being completely unfamiliar with the antenna, and I now could have it set up within a minute or two.
First contacts were from Georgia to the midwest on 20 meters, psk31 and 5 watts. Good signal reports were received and I then hunted for some DX. Reached Venezuela, Brazil and the Canary Islands quickly. I did not have much time to work it more, and plans are to find out what it can do in a true portable situation.
In closing, I was skeptical at first and put quite a bit of faith in the number of great reviews for the AlexLoop. Early in the use of the antenna I have found all prior reviews to be accurate description of the performance of this antenna. I'll do a follow-up review in 6 months as that should be enough time for more portable & maritime mobile operations. |
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| EA3HSO |
Rating: |
2013-10-28 | |
| Big antenna performance! |
Time Owned: 0 to 3 months. |
Bought mine about a month ago and didn't have time to go out and test it.
So yesterday, at the end on the WW CQ contest, I set up on my deck with FT817nd with internal batteries (2.5w) and the Alex Loop.
In an hour full of strong signal pileups I managed to work 2 us stations (W4RM - 6533.6 km, KA2EYH - 4399.8) and stations from the Canary Islands, Latvia, Cyprus, Romania and Bulgaria.
All in the middle of a lot of screaming big signals.
Directivity is not brutal but enough to feel some gain difference.
Tuner circuit works great and is really easy to get used to.
Tuning is really sharp, but after some use it's easy to find the sweet spot by ear.
Sets up in 30 seconds, stores in about the same time.
Still need to do some testing in the mountains, but its performance in the middle of urban Barcelona blew my mind.
And without the hassle of radials...
I thing my other portable antennas are going to see some dust. In the closet!
73. |
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