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A calculator for finding Hentenna dimensions

Started by Egil, January 22, 2015, 08:15:27 am

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Egil

The word hen means strange in Japanese, so a Hentenna means a "strange antenna". And strange it is. When inserting the dimensions  for 6m in attached drawing into MManaGal (antenna simulations software) gives weird results, and indicated that the antenna should be more or less impossible to match to a 50 ohms coaxial cable. And looking at the resulting radiation diagram, indicates that an ordinary dummyload would give better results "on the air".

But when making this antenna last summer, using the same dimensions with 1.8mm diameter enamelled copper wire,  an SWR of 1.3:1 was achieved whithout any tweaking. And as the 6m band had a short E-opening shortly after the antenna was finished, working into Croatia and Italy using 10W output produced good reports.

I have not bothered to make any helpfile as all available commands are explained in the program window.
Technical details can be found at Don Butler's (N4UJW) website (http://www.hamuniverse.com/hentenna.html).
His site is well worth a visit, as it is almost like a whishing well for antenna experimenting radio amateurs.

Support Amateur Radio  -  Have a ham  for dinner!

GWS

' a dummy load would give better results ' ..  ;D ;D ;D

With my available space, a dummy load might be the answer .. :)

Lovely to see someone using Creative for yet another application it's ideally suited for.

It's too darned cold here to be doing any outside amateur work - so I'm just listening to my Yaesu FRG 7700 receiver, sitting in the warm.

One guy on 40 meters was saying there's nobody on 80 meters - except when there's a contest - and then lots of folk appear.  Personally I don't like contests - too much like pollution of the valuable airspace.

I'll give hentenna a go when Summer comes.

Best wishes, :)

Graham
Tomorrow may be too late ..

Egil

January 23, 2015, 11:29:29 am #2 Last Edit: January 23, 2015, 11:34:20 am by Egil
QuoteWith my available space, a dummy load might be the answer


Don't despair OM, Some years ago I temporarily lived in a small flat on the 6th floor in Oslo. The only place to put an antenna was on a very small balcony. First I tried with a small vertical, mounted on the ballcony rail. But the noise produced by all the TV's, PC's and modems in the building (162 flats...), effectively stopped me from doing any radio work. The only station I was able to hear, was located 500 meters away...
But then I rememberred an article in SPRAT Magazine describing a magnetic loop antenna. I made one, very similar to this description by GM3MXN:   http://www.zerobeat.net/g3ycc/loop.htm.

Almost all noise was gone, and beeing a QRP-freak, my 3.5W homebrew transceiver did not even make TVI to my own TV located only one meter away , inside the window... Had a lot of contacts on 40m and 20m, mainly into Europe, plus one into Bombay...

So maybe a loop can be the solution for you?  


QuoteLovely to see someone using Creative for yet another application it's ideally suited for.


I have always used Creative Basic for applications like this. Its the perfect tool for quick development, and for testing new ideas...


QuotePersonally I don't like contests - too much like pollution of the valuable airspace


Must admit that I have been doing a few contests, but now there are just too many of them. Making it almost impossible to go on the air during the weekends. And the fact that most administrations now allow hams to use kW output makes the situation still worse.
So when the discussion runs dry on the club meetings, I use to say, whithout adressing anyone particular, that high power transmitters are for sissies. Real hams use QRP.
That always works. ;D ;D


Support Amateur Radio  -  Have a ham  for dinner!