Category: Antenna

Balun designs

Balun designs

Balun designs

First of all , please remember:
Baluns will not improve SWR (the exception is where a balun used as part of a matching network,
I like to design and creat baluns by myself. Quality is top notch. Don’t waste your money buying some of the cheap china knock-off’s. Do by yourself. Follow our balun designs. Well made.

The balun should do only two jobs.
1.Isolate transmission line
2.Provide balanced output current

Proper balun designs
A properly engineered balun will include these design points: High winding inductance (reactance) and Low stray capacitance. Very short internal transmission lines- << 1/4 wave (remember:  the shorter the better). High power components- High voltage wire and insulation to withstand high power or a mismatch. Large wire gauge reduces I2R losses. Large cores because help to prevent saturation and provide the necessary high inductive reactance values on the low bands.

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balun designs
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balun designs
balun designs
balun designs

Balun designs considerations
High choking reactance, 250Ω minimum
(limits low frequency response)
Low stray capacitance
(limits high frequency response)
Short transmission line, << ¼ wave
(The shorter, the better)
High power handling
Minimize resistive losses
Correct core selection
Robust mechanical design
Line Impedance, Z0
For 1:1 make equal to load and line impedance
For 4:1, make geometric mean of line and load impedance (e.g., 50Ω to 200Ω requires 100Ω line)

Useful Links
Balun Designs LLC – High quality baluns and ununs – The best website if you wanna buy one already built
Balun designs – nice book! Enjoy – few bucks and will be yours!
———-I suggest you to watch this nice video on BALUN designs – click down here on the arrow—–

 

 

 

 

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Travel QRP HF antennas

Travel QRP HF antennas

(Best) Travel QRP HF antennas

1) Alex loop antenna.

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Who doesn’t know the alexloop antenna? This is the best solution you can have. QRP Travel antenna per antonomasia.
This magnetic loop antenna has been designed by Alexandre Grimberg PY1AHD from Brazil. (AlexLoop.com if you wanna buy one). The AlexLoop implements a mag loop for the 40 through 10 meter bands. When packed into a small bag that comes with the purchase is perfect for Rapid Deployment Amateur Radio (RaDAR). You can use a tripod or any other stuff to use this great antenna inside the room of an hotel or, better,  while camping on the seaside…Click down here to see

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Pro: 

  • Multiband: This loop operates 7 through 30 MHz. Go from 20 to 10 meters band is really fast as it just requires adjusting the tuning capacitor.
  • Tuner: Not required !
  • Efficiency: every ham that has used this antenna is enthusiastic. 90% of efficiency I’d say.
  • Easy to transport!Cons
  • Bandwidth: Narrow! This is the price you pay. It does require retuning when moving up and down the band or changing bands.

2) Radio Shack “reel” antennas

yoyodeluxeI have used these YO-YO Radio Shack “reel” antennas for “camping” / bungalow holidays in Greece or South Italy. These consist of a 10 meters thin wire that is reeled up in a plastic case. This little tiny compact antenna is easy to transport and useful to get you on air on 30 meters band. You can connect one wire to the center of a coax connector and put an alligator clip on the other. The alligator clip can easily be connected to the shield of the coax connector or can be clipped to the SWL portable antenna. (see photo). I can promise you this is the cheapest and easy solution. You will enjoy. Some tips:

  • The angle between the wires isn’t very critical. Just adjust the shorter wire length and position a little to get a match.
  • The exact orientation of the wires isn’t very critical, either. Droop one over a balcony, hang the end from the curtains, etc. The antenna is somewhat directional broadside to the plane of the wires.
    If you are looking for a well-made and easy antenna for field use, you aren’t going to beat this one. And the price is more than reasonable.It is definitely a quick and truly portable setup! A must have!

 

MiracleWhip antenna

You are not HAM if you’ve never own this crazy antenna.
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This tiny antenna (less then 1 meter in length) attaches directly to the back of your QRP rigs (except Elecraft KX3) but it would be perfect for your yaesu FT 817 transceiver. It has a built-in tuning device. Using this whip, sitting on the table of your hotel (using at least 10 foot radial running around you) you may be able to connect the world! The best would be to transmit in CW or PSK31. I have no complaints about this nifty little device. It will never replace a Mosley 3 element beam but what it does do, it does it very well indeed. The Miracle Ducker TL works very well on 20-10 meters, with a good counterpoise. I suggest the use coupled with Yaesu FT 817 on 15 – 17 – 10 meters band!

You can always get an used one for few bucks on eBay!

Wonderwand loop antenna

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This could be interpreted like a miracle whip antenna but it isn’t. It is a miniaturized loop antenna. Tuning from 20 meters to 10 meters band. Excellent in receiving. I would say 10/10 ! We already talked about this great tiny antenna here. Ideal antenna for portable operation. Little space required, compact and it works.  Compared to other portable antennas the noise margin is down by a lot. I actually do get contacts on 5 Watts consistently.

The wire which comes with the wonderloop for the self supporting loop is very sturdy and good for the job. Tuning is very precise due to the high Q of the antenna so a slow, steady hand is needed to get the SWR for a particular frequency down to 1:1 – 1:1.5 typically. When you move more than a few KHz from a tuned frequency, another adjustment is necessary.

CLICK down HERE on the ARROW to see more travel antennas 

Best 73 de IZ0JOJ – please if you aware of new and other excellent HF antennas for portable use to take with you during our holidays – do not hesitate to write here.

 

 

 

 

 

 

ALEXLOOP ANTENNA and FT 817

ALEXLOOP ANTENNA and FT 817

ALEXLOOP ANTENNA and FT 817 ND
by Danny Garris, KJ4FH

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This is my Fully Portable HF operating System! Transmit & Receive ANY Frequency from 7Mhz to 30Mhz
1. AlexLoop WalkHam Antenna – Click here (and wait 5 seconds) to go to the website and have more info.
2. Yaesu FT-817ND

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The AlexLoop WalkHam Portable 36″ Magnetic HF Antenna will transmit and receive 20 watts SSB and 10 watts CW from 7Mhz to 30Mhz. You can carry it in your hand and walk down the beach or a mountain top, however I have found after awhile you will want to place it on a nice tripod. Your hand will become tired quickly and your hands will be free to operate the radio.

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My Radio is a fully modified Yaesu FT-817ND with W4RT’s Bhi DSP filter, MARS Mod, 500Hz CW/2.3Khz SSB Filters, One BIG Punch Mic, 3000mHa Wincamp Polymer Lithium 12.6v Battery Pak, Euro Kranker Knob (not shown), Custom Mic holder, Black Carbon fiber sport side kick-stand legs, and more.

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Everything can hang nicely from the custom tripod I made. Although the Radio has an internal 3000mHa Windcamp battery, I can use my larger 7Ah 12v Sealed Lead Acid (SLA) Battery for long hours of use along with my Grundig Headphones in noisy environments. I use a YouKits FG-01 Antenna Analyzer for Quick “No-Guess” Tuning of my AlexLoop. Having the RIGHT Tripod is The secert as you will learn most ALL other WILL fall over on windy days. I learned this the hard way! You want a tripod like this that has legs that open far enough to avoid wind fall. Get a good tripod!! Special thanks to Mike Olbrisch, KD5KC who helped me greatly in finding the right tripod to use for the AlexLoop outdoors and how to make a special mic holder for the Yaseu FT-817 neck strap. I will share this information in the article.

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I purchased my tripod from Amazon. You can purchase the same tripod in Lowe’s or HomeDepot in the spring/Summer in the garden section in the color of Green or silver however I wanted BLACK because I wanted it to look streamline and factory. So I researched for hours and found the same exact tripod Mike, KD5KC suggested (only in Black) on Amazom: “Orbit 62120 Garden Enforcer Motion Activated Sprinkler” I took the sprinkler head off the tripod and found a PVC pipe at Lowe’s that screwed right into the top of the tripod and I cut the length of my pipe to 6.5″ Next I cut 1/8″ grooves into the top of my pipe using a 1/4″ rat tail file so that my Alexloop Antenna will not spin around in Winds. The Alexloop is directional and it does make a difference so you want to keep the antenna from turning in high winds. The Alexloop will slide perfectly over the pipe! I placed a couple turns of electrical tape on my pipe to give a slightly better fit and friction for my Alexloop.

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Next I cut my water hose fitting of the bottom of my tripod and fitted a threaded pipe to “Store” my 6.5″ Notched top pipe for easy compact storing in my tripod bag. Another tip shared with me by Mike Olbrisch, KD5KC. Mike was very helpful in giving me details and photos to help me make my own customized tripod setup for my Alexloop Antenna. He has years of experience using the Alexloop with the Yaesu FT-817.

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My Threaded pipe fitting contains a brass insert fitting with threads that taps into my tripod pipe and then a 1/2″ thread metal coupling I threaded onto the brass fitting. Then I simply wrapped it up neatly in Black electrical tape to match up with the look of the tripod.

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Both the AlexLoop & Tripod are all contained in these two small bags!! A full complete HF operating system ready for Mountain tops, beach, Camping, ARES, Field Day, SOTA or DX Outings/Events are ALL contained inside these two small light-weight bags!

Alex, PY1AHD suggested a small light weight silver VIV-VPT-1250 Vivatar tripod $12.95 (eBay or Amazon) many Hams were using that fit right inside the AlexLoop bag along with the Antenna. I would ONLY use this tripod.

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VIV-VPT-1250 Vivatar tripod $12.95 (eBay or Amazon) for Use ONLY inside or for DEMOing your AlexLoop.

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The Vivatar Tripod is ONLY used indoors.

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Fully extended it can be used in a hotel room.

My Personal Favorite INDOOR AlexLoop Tripod is the “AlphaLoop” Tripod $64. https://amateurradiostore.com I like using it in the house because it does not take up so much room and is lighter and less bulky than my Orbit Tripod. AGAIN I DO NOT recommend this tripod for outdoor use!!! It fell over on me in a wind gust!! But it is a really nice tripod for Indoors. I have sat this Setup in my Living room on a rainy day next to my sofa and fireplace while watching tv and worked the World on 5 watts. Even placed it in my Hallway and did the same. It is a lot easier than moving around my Orbiter Outdoor Tripod. I Love my Orbiter Tripod! This “AlphaLoop” tripod is also nice but ONLY for indoor use. I tried both the “AlphaLoop” and “AlexLoop” Antennas and Hands-down the AlexLoop won for many reasons I will not go into now.

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I placed 2 rows of electrical tape on the AlphaLoop tripod just like I did on my Orbit Tripod to give the AlexLoop Antenna a good fit. The I took a small hacksaw and made a mark on the pipe so I would know where to lock my tripod at for best fit for my AlexLoop Antenna. This is a really good-looking tripod with a good fit for the AlexLoop BUT ONLY FOR INDOOR USE!!!! You will want the Orbit Tripod for ALL OUTDOOR USE!!!

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The AlexLoop Antenna is a Wonderful HF Antenna! I’ve had so much fun operating with it. I have it here setup in the parking lot at my Electronic Service Center. The Orbit Tripod looks almost Factory along with the AlexLoop and that was my intention. The legs spread out far enough that wind will not blow it over.

I took three nice Velcro straps available at most hardware stores and strapped the coax of my AlexLoop to the mast to keep the coax from dangling around in the wind and to give the AlexLoop a Stream-line appearance. This does not affect the performance in any way.

The AlexLoop works all Frequencies from 7 Mhz to 30 Mhz Continuous with a low SWR that is adjustable by turning the knob on the bottom of this box. You tune for Max reception and fine tune from there. When I first got my AlexLoop I was on the air in 5 minutes. I had no SWR meter, I just tuned 20M for max reception and worked W1AW/4 in GA with a 5/9 Signal running only 5 watts from my Yaesu FT-817ND. I have a Brand-new Buddipole and Buddistick that I have not even taken out of the bag yet since I got my AlexLoop! I can take a 5 minute break and grab my AlexLoop mounted on it’s Custom Orbit Tripod and walk outside in my parkinglot and make a contact in less than 3 minutes!!! It really brings back the FUN of Amateur Radio w/o all the fuss!!

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I invested in the YouKits FG-01 SWR Antenna Analyzer available from Ten Tec’s Website after much research and I’m SO GLAD I did!! This thing makes tuning ANY antenna a breeze!!!! I can REALLY FINE TUNE my AlexLoop for MIN SWR and that helps get my signal out even MORE!!!

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I can hang my Yaesu FT-817ND from my Orbit Tripod along with headphones for noisy outdoor use and my custom made Mic clip for the side of my neck strap! I am tuned to 14.300 Mhz USB and working a the Maritime Net running only 5 watts. I can pick up the entire tripod and radio with one hand and move it around or walk inside the house and continue operating. I also have TONS of Fun on DIGITAL modes such as PSK-31, JT65-HF, APRS, RTTY, SSTV, CW, and more using my Signalink USB and Acer 10″ Portable Netbook which opens a whole new FUN world to DIGITAL Communications!! You can work the World with less than 1w with PSK-31. So 5 watts is no problem!!! I can set this Tripod inside my house next to my sofa and with my Netbook work dozens on PSK contacts by my comfortable fireplace while watching TV! Click at the end of the page on the arrow to see the video about the LOOP antenna!

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You will want to do the Mic clip Mod because when using the Yaesu FT-817ND around your neck the factory mic clip is located on the shoulder part of the strap which is behind your neck. This is a REALLY nice and very easy Mod to do yourself. You will want to locate a WORKMAN MH4 or MH4B Mic Holder of eBay $6.50 and removed the adhesive backing and using a dremel tool with a small 1″ cutting wheel make a cut on the bottom and top to allow the strap to pass thru and place it on the neck strap as shown. This was a very helpful tip given to me by Mike Olbrisch, KD5KC.

I placed 2 pieces of electrical tape on my top PVC pipe to allow the AlexLoop to fit perfectly without too much play or too little play! About 3 turns of tape was perfect. Yours may vary. The notches allow the AlexLoop to not spin in high winds. Also note how far the legs stretch out giving excellent stability. After all this WAS a Sprinkler tripod and lots of water pressure was designed to spray out the top of the tripod so this was the PERFECT tripod to use for the AlexLoop! (Thanks again to Mike Olbrisch, KD5KC for his helpful suggestion). Mike uses 3 of these tripods he Loves them so much! Except his are Green because in the dessert heat things that are metal and Black are not good to grab onto!! A thought for those who will be in Hotter climates. Me, I am on the beach and flatlands of Eastern NC. When I’m not using my setup I store it as seen below ready to go inside my Electronic Service Center so I can use it at any moment. I lower the tripod so I can get it outside the door, then raise it and operate in less than 3 minutes!
Click down here on the arrow to see the video about the LOOP antenna! 73 de Dennis 

 

 

 

 

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Wonderwand Loop Antenna review – 9H3FC

Wonderwand Loop Antenna review – 9H3FC

Wonderwand Loop Antenna review

We have received this short but nice review from Chris 9H3FC / G4UDG.

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With a family holiday planned for Malta , i made plans to take my FT-817ND and a Wonder-loop 4010  antenna with me, i applied for a callsign and was allocated 9H3FC ,  given the limitations of a hotel apartment i chose the loop antenna as it needs no radials, no support/tripod,no coax, easy to tune , operates on 40 to 10 Mtrs, and folds down into a very small box for transport.The QRP station was set up on the balcony of my apartment , with only a ” concrete ” window to the world for the RF to escape !   , I operated on 10 Mhz to 28 Mhz. CW @ 5 Watts. Click on the arrow at the end of this article to see the video on how this QRP loop antenna performs. The results were very encouraging , after one week operating for about 1.5 hours per day i managed 50 qso,s into 23 DXCC , including G , GI ,OX , DL ,EA6 , OE , SM ,YO ,HA ,K3 , 9A ,N4   etc.  A most enjoyable experience and the little loop   ( 21″ diameter )  worked very well for me indeed.

 

 

 

 

 

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73 de  Chris    9H3FC / G4UDG.

114837-magic-marker-icon-arrows-arrow11-rightclick on the arrow to see the youtube video!

Alex Loop antenna and remote tuner

Alex Loop antenna and remote tuner

Alex Loop antenna and remote tuner

Alex and Ricardo Lima Caratti are working together on a REMOTE tuner for the famous Alex loop antenna.

This video is about a remote control prototype for Alexloop.  This prototype works via Bluetooth. 
You can control the Alexloop via any Android mobile device. Obviously you can’t remotely manage this system at distance like 100 meters but it could be useful when you’re at 5 – 10 meters and you don’t want to leave your chair 🙂

You can have more info about Alexloop antenna on the website http://www.alexloop.com/
The remote control project project by Ricardo Caratti is Open source:
All the details about this … are on https://github.com/pu2clr

Here there is the second part:

And also:

Please write your comments down here.
Share with us your opinion.

Best QRP antenna – Our survey

Best QRP antenna – Our survey

Hello every body.

Few weeks ago we asked in our forumWhich is the best QRP antenna for our rig such as Yaesu Ft 817?

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It seems that the END FED antenna is definitely the best antenna you can have on the market.
It is easy to deploy, in any configuration, easy to transport (less than 10 cm of space and less than 50 gr). No need of Auto Tuner. Click down here on the arrow to have see our review on end fed antenna (LNR precision – trail friendly 40/20/10 meters band)

It’s the end fed antenna Ultimax vs End fed antenna Trail Friendly by LNR precision?
What about G5RV filare antenna, or the MP1 superantenna for our QRP ?
Do you know also the Buddystick or Buddipole antenna? Yes! They are great …but also expensive.
Why spend more if you can have have better results with cheaper hand made antenna?

Which is the best ANTENNA for QRP? this is a great survey!

Wanna say yours? Please partecipate at the topic.

If you would like indeed to see a review on END FED ANTENNA Trail friendly 10/20/40 mt LNR precision please click down on the arrow!

73 de IZ0JOJ.

VU3SXN QRP vertical buddy stick

VU3SXN QRP vertical buddy stick

VU3SXN presented on our forum his antenna:

Home mande QRP vertical buddy stick type foldable antenna capable up to 80 watts

I always wanted an antenna for my qrp ft-817nd ,which can be used anywhere in any situation, and which can be carried with us anywhere, i present a small wonder whip foldable antenna made up of 5to 7 elements which can be removed when the antenna is not in use and when required can be connected to one another for the erected vertical element , the vertical element is approx 4.5m in length or approx 14 feet.

The antenna can be tuned for minimum vswr by choosing the multiple inductive tapping in the end of the antenna, they are approx 20 turns tapped at every 2 turns, 10 taps in total, connect the patch cord at the tap which gives the maximum noise and that’s it,you are tuned for the minimum swr on that hf band.

The vertical element is recycled from an old army antenna allmost 35 years old but still rock solid, you can find a lot of these on ebay.com,

I got it from a local market recycle shop for 2$, then the pvc pipe is used for making the vertical stand , it also costed approx 3$, the bill of materials never never raised up from 10 american dollars.

Its definately a great bang for the buck.

A good vertical tuner can also be used in this antenna.”

 

I Built it here in Italy. I spent 23 euros. Great deal.
It is a decent portable QRP antenna. I recommend all of you to build one.

73 de IZ0JOJ

Review of Trail Friendly End Fed Antenna by LNR precision

Review of Trail Friendly End Fed Antenna by LNR precision

End fed antenna

The end fed antennas are full length half wave dipoles where the coax connector is at one end of the dipole, where it is most needed. The big advantage of these antennas is that can be mounted horizontally, vertically or as a sloper. No  counterpoise is needed.

End fed antenna by LNR precision

This antenna is very small and well built. The only weak point is in the antenna radiator which attaches to the matching network without any strain relief. That would not normally be a problem and do not think it would be an issue with normal use.

DSC01455DSC01457DSC01458IZ0JOJ End Fed antenna installed @ my university accommodation in Bristol
Can you see it?

My opinion
It is a very versatile antenna, stows-away into a very small volume,  power rating of 25W and size. Bandwidth is amazing: around 200 khz. No tuner is advised to be used. The matching box that is about 1″ x 1″ x 1.5″that has a BNC connector.  Weight is 3.5 ounces. My version is the 40/20/10 meters band Trail Friendly . 75$ + shipping from USA store. The construction is excellent and I have never ever had need to call the customer service but on eham.net reviews some ham radio op did have need to call the store and seems they are quick and gentle.

My test

SWR on 10 meters band (28.250 mhz)  is  1:1
SWR on 12 meters band (24.900 mhz)  is  2:0
SWR on 15 meters band (21.200 mhz)  is  2:7
SWR on 17 meters band (18.100 mhz)  is  3:5
SWR on 20 meters band (14.150 mhz)  is  1:1
SWR on 30 meters band (10.100 mhz)  is  3.2
SWR on 40 meters band (7.050 mhz)    is  1:2

Conclusions

If you travel around the globe, if you need a stealth antenna, with easy deploy …and easy transportable,
the end fed antenna is what you need. If you need a strong, reliable, with very good construction, excellent service,
you need a LNR precision end fed antenna. Very good value. On Eham it has been reviewed as 4.7 on 5.
Click down here to see a nice video about my LNR precision END FED ANTENNA and ME working in 20 meters band.

Merry Christmas from IZ0JOJ

Merry Christmas from IZ0JOJ

Portable operation QRP from Termoli (CB) –

Calling CQ on 15 meters band – End FED antenna by LNR precision Trail friendly (10-15-20-40 meters band)

What to say? I spent 1 hour doing QSO over all ham radio bands.

I also did PSK31 and this was the reception map… get your own conclusions:
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73 de IZ0JOJ

Alexloop HF antenna review – cost, considerations and tips

Alexloop HF antenna review – cost, considerations and tips

Alexloop HF antenna review – cost, considerations and tips

Here you find PY1AHD describing and introducing us his great antenna that I personally tested with my two QRPs ( Icom 703 and Yaesu FT 817 ND).  What can we say on this loop antenna? Only one word: excellent. Let’s review together Pro & cons.

Pro:
– very portable, light.
– excellent reports
– magnetic antenna (low QRM)

Cons:
– price (more than 300$)
– no remote tuning available yet

alex_1The Alex loop antenna is inside this bag ! 🙂

Before there were two versions of the AlexLoop (a kit using copper tube for the radiating element with the cost of $199 US.) The other and now definitive version is the so called “WalkHam“, which uses stout coaxial cable (RG 213) for the main loop and comes ready built in its own custom made carrying case similar to a laptop case. The price of the AlexLoop WalkHam is $349 US.

alex_2-2 Alex loop antenna – as soon as you open the zip !

The loop is 1 metre in diameter and tuned using an air spaced variable capacitor with a 3:1 reduction drive giving a 4 : 1 tuning range: 10m – 40m. Most magnetic loops including home-made ones only manage a tuning range of 3:1: 10m – 30m or 15m – 40m.

Once again Alexander PY1AHD showing off his antenna!
The antenna is designed for QRP operations (max 25 watts SSB or 10 watts AM/FM) and can be hand-helded and tuned with the thumb during walks on pedestrian operation. You can also make it supported on a tripod and turned freely to kill noise sources. The AlexLoop will work perfectly only 1 meter above the ground, so you can support it on a tripod an operate confortable seated on a camping chair.

The AlexLoop is the perfect company for your camping, travel, hotel, ship as well it will work perfectly on balconies and windows presenting a omnidiretional radiation pattern. If you like to see an excellent VIDEO on how to improve performance of this great antenna (Alex loop antenna hf) please click down here on the arrow.

 

 

What do you think about this antenna?  have you ever used it? 

73 de IZ0JOJ