Unlocking the Secrets of the Half Square Antenna: Understanding its Design and Functionality 

Callum, you're good keeping my mind active and fresh. I thank you, a million+1

Build all the things! I always enjoy and learn from your videos.

Thanks for modeling this Callum! I’ll try it end fed with my 56:1 auto transformer. 73zzz!

omg! this is extremely simlar to a military feild expeidant antenna!! just missing the "slide"... awesome! please build this..!! the slide is the spot where you feed the antenna..to dictate the wave..( if my memory serves me right.. back in my military days..) looks soo familair though!! AWESOME VIDEO ALWAYS!

Yes, build and test. 👍

Half-Square Antenna's are great, especially on Field Day. From my Illinois FD Location, I can set them up to be Bi-Directional to NYC/New England and Southern California. They Null Out WA/OR and FL very good. Ideal for QRP. They don't need Height to perform well, 20' is good for 20m and 15' works on 10m and 15m. A pair of Fibergalass Step Ladder's, some Schedule 40 Plastic Pipe 1" or 1-1/2" and a couple sand bags and you're in business. I have never tried 80m, but other than awkward, 40m was quite nice. On 10-20 they can be "rotated" easily if not using Trees. 73 de kc9ih

The full wave version for 20m can be voltage fed at a bottom corner with an efficient 56:1. Then you’ll have a nice cloud burner half wave on 40. The broad side gain as a full on 20. For 15 and 10 you’ll have gain about 3dB or sometimes greater than a quarter wave vertical. On 10m it’s largely omni directionally so.

For sure build one , I put one up just for fun 6 years ago for 20 meters with a qrp radio as a demonstration for a friend . We had fun into Canada and Florida from IL. Lots of people make them In Florida with screened in porches that live in HOA . They use the aluminum framework somehow .

When using a reflector, the formula to calculate the distance to space the reflector is wavelength/5.26=distance in meters

Yes Callum, please build one . I have built one as an end-fed with a 9:1 unun, 2 masts at 25 ft, and 102 ft of wire (British military kevlar core wire from DX Commander) I have also configured the same parts with one mast and the other 77 ft as a sloper. They all seem to perorm well, but I havent compared them against any other antenna.

Yes, I would love to see this build! 🙂

Great video, .... again.

The Half Square is my very favorite DX weapon in my arsenal. You can also do a whole lot with one wavelength of wire folded up in different ways.

Love this antenna, my best 40 meter wire antenna ever 🙂

Would like to see that in action Cal - So my vote is to build-it lol (Only because I have two trees in my garden) 😉

They seem to work well on the lower bands. I made one for 20m band and had it up quite high, feed in the top corner direct with 50ohm coax. Made some contacts but it didn’t seem to out perform my end fed.

Hi Cal , I have had up 2 versions of Half Squares designed for 20m voltage feeding first version using a 9:1 UnUn all wire and squid poles to support, 2nd version using two vertical aluminium tapered tubes 5.2m long and your fantastic quality insulated wire horizontally between them as the phasing wire 10.3m. The vertical elements are mounted on fibreglass insulators on 4x2" timbers 3.9m high, with my 9mx9m shed as a counterpoise fed via an Icom AH4 remote Autotuner. Both versions work extremely well especially on 20m with DX from Australia to Europe and Australia wide strong signals on 40m. I wound love to see you do some testing on Half Squares and your findings Cheers Greg VK3KV

I believe you should have a Half Square in your line up to sale. There's several good articles on the internet about this antenna. 73

now you got me thinkin would be interesting to see how it works.

Hello, yes will work and works , I’ve build one half square for 20m band for my QRP filed days activities, and the results are amazing ,definitely you should build one and test it out with little more power then my 1 to 5W. My best QSO using this antenna was VK station and me running just 1W . Many 73,s de M7SZY.

used have run half square antennas on 15m, 17m, 30m, 20m, and 40m with very good results. If You want a proper DX monster run a phased pair of half squares side by side 1/4wl apart. I used a carefully matched pair of half squares for 17m with Christman phasing method and battered lumps out of Japan and Malaysia with 5W :-) I prefer to run QRP and make the antennas do the work. - also used half squares strung between trees operating away from home to bag a load of contacts in S.America. Well worth a bash. 73 de MM7WAB

HI Cal , you can also feed it at the bottom of one of the down legs with a 49/56:1 unun and it will work on the higher bands as well and give you still the gain at the original designed frequency whatever that maybe, I am going to build one and see how it works out. Love your work keep it up. Regards Dave.

Would love to see you build this or the bigger “Bobtail curtain” version! I’ve been interested in these antennas for a long time. 73’s! 😁 WB3CFN

I have talk to hams that really like this antenna. I have been meaning to build this for 2 years but just haven't had the time.

If you have the time, definitely build one and demo it.

Hi from ST2KI ..Ilike be the way you present ideas 🎉

I have been thinking of building a half square or the one with three vertical elements called the Bobtail Curtain for the last 35 years now. Never got around to it. I would love to see you put one up and see how it performs in the real world - SWR etc thanks

Go for it.

I would love to see you build a half square antenna, I recently built my first antenna. The project started as a plain old 40 meter dipole that morphed into a fan dipole with 3 elements... 40, 20 and 15 meters that also gives me about 1/3 of 6 meters without the need for a tuner. I would be interested to find out if this half square could be done with a fan dipole...

Another possibility is to put a third vertical wire in the middle and then the antenna becomes a bobtail curtain. You can feed it at the top corner just like you're doing now directly with 50 ohm coax or you can feed it at the bottom middle wire using a 49:1 transformer. If you build the reflector the same size instead of making it slightly larger then you can choose which direction you want to favor just by switching your coax connection to one antenna or the other! And the other cool thing is these antennas can be flipped upside down so that the coax connection point And the long horizontal section is at the surface or ground level and the vertical elements are pulled straight up to the trees.

Ive loads of trees around me and would love to see your build and results. de Paul.

Half square, looks very interesting. Yes please build one. I guess it will always be a single band antenna?

I guess I'll need another roll of Dx10 Cal, very interesting video mate, I'm limited to what i can get away with here but i do happen to have two very tall trees close enough to hang it. Watch this space El Lordo Callumski.

Build Away my Man!!!! Have some fun!

Great video! I would love to see you build a half square. I’m going to build one too and test it out here in the middle of the US. 73, Adam N0ZIB

I've recently built a 20m half square with two fishing poles and some wire. Very light and I did 5w with it and it was a surprise to those that I worked with it as I didn't call /qrp. I just added it at the end of the QSO that I was 5w. Most were surprised as my signal was stronger than they expected from a QRP rig. That said, I wasn't doing well with anyone off of the sides of the antenna. It was also pleasantly quiet to listen with. I used lead fishing weights to hold down the ends of the vertical elements. I think this would be a good project for 40m with the 12m masts. I don't think this would fit with my Jackite 30ft. masts unless I make a small inductor to shorten the two verticals. Deploying it by myself also took a little planning but eventually worked out. Thanks for the video! de WE2DX

Great video , the only way I could fit my end fed half wave in was to run it similar mine is 10m on both ends vertical with 20m horizontal interestingly it works superb on 80 which obviously it’s a halfwave for but as a half square on 40 being a full wave on 40 it doesn’t work as well as my old end fed half wave using half the amount of wire , I’ve always presumed lobes are being produced being the second harmonic, it is being fed via a 64 to 1 at 2 ft above ground

With my weird lot on the edge of a cliff, this might be the perfect antenna. Build away

Callum, what do you think about alternate feed points for these? I've been modeling one at 33% from the bottom of one leg with a 4:1 or 6:1 balun and it seems to turn it to a feasible multi-bander.

Go for it Cal!!! Jim M7BXT

I wonder if you could model a half square with a reflector AND a director? If so, you could assemble quite a blowtorch to point at an "area of interest", sans conventional tower and three element beam. I also wonder if it could handle other bands with additional vertical elements. Might be interesting at 10/15/20 where the dimensions wouldn't get unwieldy? 73 DE W8LV BILL (W8LV/VE3 prepandemic)

Would live to see this one built. I've heard of the Half-Square but never had any experience with it. I have 3 100m rolls of DX10 coming for my 80 loop project, I can use some of it to build one of these!! Do I have enough trees?? I need to plant more!! Or order some 12.4 or 18 m poles!

Hello, I don't know how to use antenna modelling software so I have to ask. From my understanding the vertical elements of the half square do the radiating. So does the horizontal element need to be at the top? It would sure be easier to set up by turning the antenna upside down with the phasing line at ground level and feeding it without a transformer. I understand the tripping hazard but for portable work where I'm by myself it would be easier to set up. What does the modelling software come up with?

M0OLT , Hi Cal.. Great to chat at Hamfest.This is what I bought pole for. I already have one pole. Is it the top ‘wire’ length only that needs to be half wave? Can I have drops nearer and bend top wire or must the physical distance between drops be half wave? As you know I only have 7m yard. I want 10m for 14Mhz. Dont want build just a28Mhz Too wet at the moment so wont rush yet.

I built one of them anttenas but fed mine from the base for 40m worked verry well into euro land never worked dx with it chris

Calum, i have know a ham that go to mountain tops in so-cal with a double bobtail curtain and is able to make multiple qso,s across the US on 15 meters. there is also a fellow in Australia doing a similar thing not sure what band. Andy N6AJH. btw i am in Wroclaw Poland not NC USA

Dear Commander Callum, thanks for this. Would a balun (1:1) be required, or useful, at the feedpoint?

What would it be like if you put the driven element in the centre and a reflector either side would it be equivalent to a three element beam

How far away from the antenna do you built the director and how much bigger is it? Hoping to build a 20m half-square to SSB to Bouvet island from Southern California, USA. Also, what do you do w/ the drooping ends? Tie a weight there so it doesn't flop around in the wind? Appreciate it! Good overview.

Hello! Thank you for the great video. Can you share the MMANA-GAL file for half sq. antenna? I build one, but when I specify the feed point to be at the end, the impedance is looking very strange ...

What ya could do is from the middle section towards the from drop just replicate that twice and have them joining in the middle,i would do it myself but ive only got a tiny yard😐

Hi Callum Hope you are well. ... I run a rectangular loop in the vertical for 10m ... It is fed in the middle with a 240 toroid for stopping any RF, swr is 1.1.1 ... I have the antenna on my QRZ I would imagine it possibly has a 3db gain but not sure, any chance you can model it on MMANA. I have to say it works exceptionally well... Mike M0csi ...

Can you add more bands if you add a third or fourth leg

soccer goals will be disappearing and repurposed for added antenna elements / gain

I have tried some similar antennas, but was never sure how high above the ground might be best. This example here has the vertical ends 12 inches above the ground? Is that right? That's just a general gap above the ground, regardless of frequency,? With just the length of the wires cut for frequency. That makes it easy then. I'll use some para cord to attach the ends to concrete blocks, to keep them from blowing around.

So a phased array with one fed 90° lagging would have greater front to back?

Cal it's very similar to an EWE antenna?

OH thats great! what if ya elevated the half square? Feed it at the end mabe?

Since this is a full wavelength of wire, you could feed it at the end with a 49:1 transformer. Still optimum gain on the design frequency, but resonating on half the design frequency, as well as all harmonics of the "half freq". It is also possible to make phased arrays, two half squares 1/4 wavelength apart. Then it is possible to switch the main directions. I would very much like to see a build and test of that, as you have an antenna range ;) Have you ever considered trying the Bobtail Curtain? This can be fed in similar ways to the half square, but it is a single band antenna only. The Bobtail should operate like 3 quarter waves in phase. I have considered building a Bobtail (maybe two phased) for, say 15 or 10m, just to have some gain from my garden. Vy 73 de Jan, OZ9QV

how well would this work on 11m? all so how about height? looks like something you could move around on 12m and up.

allright MR dx commander, i like your channel i find i very interetsing and i really do learning somthing here. but i am going to take the ham test in less then 30 days in Norway so the 26th november is my dday. I have used a full pen and one and a half book to write while i learn, i have yellow papers everyvere in my book. but there is one thing i just dont understand and that is the Superheterodyne Radio in a complicated easy way. Can you help me. I will have that on my test, they told me that. And how to i understand this Middle Frequency. Thank you sir.

PLEASE BUILD IT

Build it Cal you'll like it I have one for 20m .....DE W3LES

Well did you build it?

I predict it to be noisy on the receive

Calum

If you half the square from top right to left bottom and half it you get the left triangle Independence day

A couple comments. You talk in dB. I think the reference is dBi in your modeling program? Anyway I have built several half squares. The one for 80 meters may have been my best antenna ever! However it all depends on height of the antennas you compare it to. On 80 meters you need a dipole higher than most hams can afford to beat the half square. On 40 a dipole usually equals or beats it. On 20 the dipole at almost any height really beats it! A dipole at half wave high has close to 8 dBi gain. Very hard to do on 80, not too hard to do on 40 if you have trees and on 20 and above half wave is easy to achieve. If interested here is my club presentation on the 80 meter bent half square: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2SBGdPMnH-E.html

Callum, you might want to fool around with a 10m version. 10m is hot right now and likely going to stay that way for a bit. I am thinking about doing a 10m 1/2 Square.

Why not build the second one as a director? Less wire, and directors have a stronger influence in most designs I am aware of.

@1:38 that's 1/2 one way, 1/4 wave up, 1/4 down, that's a wavelength. Can you not add? 1/2 not 3/4. Seriously.

GREAT VIDEO BY A GREAT MAN ABOUT A GREAT LITTLE HALF SQUARE LOL m7rfs thanks cal

Heck yes lets see this thing come to life. not like you dont have anything going good stuff as always Callum de W9US

Build it build it. Did you build it already? ciao W6LDM