2m Hentenna

[VK2VHF]

I was thinking of building a hentenna for 2m SSB work this weekend using copper pipe. I am attracted to the size and shape - it provides about 3db gain and when mounted vertically it provides horizontal polarisation which suits my roof!
Just wondering what experience people have had with this type of antenna for horizontal work. Appreciate any feedback Cheers Adrian.

[VK3PF]

Hi Adrian,

I have not used one. But, have you seen the July issue of Amateur Radio?? There is a report on a Hentenna on 6 m, including gain diagram - reports almost 10 dBi at 5 m above ground. The report starts on page 25.

Good luck and let us know how it goes...

Cheers,

Peter VK3KAI

[VK4CZ]

Adrian

With the growing interest in home-brewing that's become evident here on the forum (between antenna and amplifier projects), I think you've just been volunt'old to document and share your experiences.

Of course... to be published first here!

[VK4FP]

Adrian,
Remember a couple of cycles ago,there was quiet a few JAs using them on 6m .They had quite respectable signals my way.so I decided to build one last year.
Using a Hentenna for 6m .Superior performance to my commercial 5/8 vertical.Bi-directional broad lobes,but very sharp nulls off sides.Simple to tune.
Mine is all aluminum construction...
73s,
Lloyd -Vk4FP.

[VK2VHF]

Adrian

With the growing interest in home-brewing that's become evident here on the forum (between antenna and amplifier projects), I think you've just been volunt'old to document and share your experiences.

Of course... to be published first here!

Ok leave it with me fellas. The most challenging part seems to be mounting on a non conductive mast. I've seen a few hints on the web so will give it a go.

Here is the design I intend on following....http://www.neighborhoodlink.com/pdf/clu ... 186784.pdf

Will report back with some pics etc as soon as the kids give me some spare time in the workshop.

[VK2VHF]

Quick update ......I spent an our or so cutting the 1/2 inch copper pipes today and have attached some pics of the job so far. It was more difficult than expected because the measurements needed to include the elbows and tees which add about 17mm each.

The bottle is included as a reference to give you a feel for how compact the antenna is. Given it was cold I could not let it go to waste.

The photos show the fitted joints which have not yet been soldered. I should probably check the VSWR before making the job final.....a job for tomorrow.

Cheers...Adrian

[VK2VHF]

Quick update # 2

Today I managed to solder the joints and it was much easier than expected (only one burnt finger ).

Note that I used nothing more than a small torch and regular electrical solder as shown in the picture.

Next step is to fix a female N connector to the feedpoint.

Adrian ~VK2VHF~

[VK4WDM]

With regard to all the cackling about the hentenna. I don't think I would use one as my only antenna - I don't like putting all my eggs in one basket, but it would be good to stop the crowing and ruffle the feathers of the "top of the dx perch" roosters by working some real dx on one and moving up the pecking order. The down side is that they might consider it a foul deed and send the axe man to my nest. Perhaps I should chicken out and stick with my yagis.

73

Wayne VK4WDM (sorry, I could not help myself).

[VK4WDM]

OK, after my previous "puny" post some serious discussion!

I must confess that I have never seen this design before but it certainly has some engaging features. You could make ones for 6m, 2m and 70cm and feed it with a single line with a multiplexer at each end - an ideal "low profile" home QTH antenna system or for portable use (I wonder what the spacing would have to be to prevent interaction degrading performance?

Anybody know what happens if you add extra loops - a reflector and director, do you get extra gain?

What happens if you mount one lying flat? Say one cut for a HF band and mounted above an iron roof?

Can a HF one be multiband if fed via a tuner?

73

Wayne VK4WDM

[VK5ZD]

Looks like a slot antenna to me (imagine a skeleton slot yagi with no reflectors or directors).

73

Iain

[VK4QB]

Hi all,
Looks like your'e right Iain. Re gain with more loops for and aft, then wouldn't it be a loop antenna ? albeit a square loop ? and they work ! Just ask Adam 4CP he's got one for 23 cm. As for using it on HF, a Quad works and thats a full wave ! Is there anything new ? Yes ! The shape .
Brian 4QB

[VK2VHF]

I have just tested the antenna at 3m above ground on my analyzer and the results are listed below -

Freq / VSWR
144.100 / 1.4
144.500 / 1.3
145.000 / 1.1
145.500 / 1.1
146.000 / 1.1
146.500 / 1.0
147.000 / 1.0
147.500 / 1.1
148.000 / 1.3

As you can see the antenna is quite broadly banded although it is centred around 146.750 instead of 144.200 despite following the plans precisely .

To lower the resonant frequency I will need to lower the height of the feedpoint.

Further tesing and experimentation to come!

[VK4QB]

Good one Adrian,
Seems quite a different approach, something like 2 Jpoles with the ends joined Mmmmmm
73
Brian 4QB

[VK2ZRH]

To lower the resonant frequency I will need to lower the height of the feedpoint.

Actually, Adrian, you need to lengthen the sides by 18 mm

And you need to address the balanced-to-unbalanced transition from the feedpoint to the coax. Yeah, I know, various descriptions of how to build the Hentenna ignore this - including the article in the July 2009 AR magazine (page 25).

You could slip a half-wave sleeve over the coax outer insulation - an Alfoil wrap-aound, a la the VK7MO trick, or a bunch of suitable ferrite rings slipped up the coax to behind the coax plug.

Good luck with it.

2c (plus GST, minus GFC - still 2c).

73, Roger Harrison VK2ZRH

[VK4DD]

Adrian,

Here is an idea to lower the resonant frequency of this antenna without building it twice...

I once build a quad antenna from insulated wire and learned the hard way that the bare wire and insulated wire have different resonant frequencies.
The insulated wire resonates at a lower frequency.

The idea is to tape it up with PVC tape and weather proof it at the same time.
Use some plastic dip or what ever just make it fatter ... paint it first, and than tape it up.
That will lower the resonant frequency...
How much lower ...? I suppose that will depend how thick you make the coating....

Perhaps you can also experiment with different methods to mount the N-connector.
I have a feeling that different methods on how to mount the N-connector will give slightly different resonant frequencies...

The other question is should we call this thing H entenna or H antenna...

Cheers
Ron
VK4DD

[VK3FKRK]

hi there can you tell me what dimension you used to build this antenna? i think there is a differnce between the inperal and metric dimension in the instractions
thank for your time
ken

[VK2BLS]

Hi Adrian, (this is my first time on logger).
Tks fer qso today, You have done a nice job on the 2M 'hen' looks good. If you make it adjustable like you suggested will allow more testing. I have googled 'Hen..' where reflectors have been fitted and multiple hens setup like 'quagis' all very interesting. Several 2M 'hens' setup like a 2M phased array, would be compact for vertical use. If someone could help with info how to match them up? The 6M 'hen' is testing ok, I have a recording from vk7 coming, of 6m rx end, but too much 'plasma tv' noise my end for qso exchange. Cheers, Darrell

[VK2VHF]

Hi Ken,

hi there can you tell me what dimension you used to build this antenna? i think there is a differnce between the inperal and metric dimension in the instractions

I used the metric domensions shown in the link to the PDF I posted earlier. I must admit I did not check the conversions and took them as Gospel. Oh no, could it be that you cannot believe everything you read on the web.

Anyway, I managed to lower the feed point by 1cm yesterday (just cut the pipe above and below the feed point and used 1/2 inch joiners) while keeping the same overall dimensions. VSWR result was marginally better at 144, but the rest of the VSWR curve shifted slightly upwards

Some thoughts to consider:

- Balun of some sort should be used
- Impact of pipe dia?
- Should the loop measurements be inside, centre or outside circumfrence? (I used outside)

So while 1.3:1 VSWR is pretty good, I really wanted 1:1 because my rig folds back to 50% power at around 1.3:1.

Cheers Adrian

[VK4DD]

Adrian,

- Should the loop measurements be inside, centre or outside circumfrence? (I used outside)

I would have measured it up center to center...

The text of the article also mentions that the VSWR is best at 146 MHz.
But this might be related to the dimensions in the text..? here he suggest to cut this section that long etc. etc.

On the other end the the table with the dimensions mentions 144.2 as design frequency.
Perhaps Adrian can compare these measurements on his ...

Here in Brisbane ... this good be a very good 2m Es antenna for the summer....
I could work North QLD and VK2.3 and 5 with just one antenna position

It will do good work on the monitoring the band...
And I am wondering if I should make this antenna also for the top end of the FM band... to monitor the propagation..
10 Mhz band width is more than enough...

73 Ron
VK4DD

[VK4WDM]

If you call it an H antenna you won't have to put up with my puns. H entenna is sure to egg me on!

73

Wayne VK4WDM