WINDOM ANTENNA

I'm using homebrew Windom-Antenna recently.
In the total length of this antenna is 41m, height is about 11m, and diameter of element is 2mm.
However, it is up only about 4m height from a metallic roof.
I modified this antenna originally used as Inverted-V type of 80m band Dipole a little.
The feeding point of this antenna is located 13.6m from the edge of Element. Yes, it is Off-Centered.
BALUN of making which uses two cores, converts impedance into 1/4. The core is the one of about 4cm in the diameter. so there's no problem in the input power 100W at all. Because two cores are used, I think as much as 500W safe in power.
The diameter of the wire rolled in the core is about 1mm.
The VSWR to frequency is shown as follows.

In 21MHz, VSWR exceeds 3. However it is likely to QSO with the domestic area, if Antenna-Tuner is used. I did not obtain good results though I measured its VSWR with 10MHz and 24MHz besides <showing up>.
I think this easy structural wire antenna is Very FB. Because I can QRV on multi BANDs without switching some antennas.

By the way, I had one question. This antenna might be a name of "Windom" why?...
I thought it might designer's name or name of a place of development ground.

The answer's as following e-mails via radio-amateur's FWD-Net.

Dear friend, i have a self building Windom; it is a dipole of 80 meter with the connection at 1/3 of the lenght: in this point the impedance is 300 ohm, and with a balun 1:3 i obtain 50 ohm; for the band of the 21 Mhz i put a second dipole only for this band, connected ad the same mode of the other; the lenght of this is 2.3 + 4.6 meters.
In a test with a vertical groun plane 5 band, the windom result better in 14 7 3.5 Mhz; using a good antenna adapter, it can be used in 1.8 Mhz.
This antenna is named Windom because was bilded from Laurent Windom (W4DZZ ?) around the 1930.
It' s not a long time that i use this antenna and i have some thing to understand about it; in any way i'm really satisfate from this antenna.
I wish to you to have big satisfation using them.
Best 73 an good DX. Ciao de Franco. IK1OWB@IK1JNS.IPIE.ITA.EU

Hello Tada !
The "Windom Antenna" was described by Loren G. Windom ( QST, Sep 1929, pp 19-22, 84) so this kind of antenna was named after its inventor.
73 / Peter, DJ2ZS@db0gv.#hes.dl.eu

The windom is called after its inventor.
Here I use a windom antenna on 80 - 10 m. the ntenna is 41 meter long.
13% off center I feed it with 300-ohm open air-spaced feeder. I use an antenna tuner with the balun coin connected to the antenna tuner. The antenna hangs in zig-zag between some trees. I am very pleased with it, it works quite well locally and on DX. Thought this might be of interest to you..
Good luck!
73 de Egil. LA8HF@LA4O.OSL.A.NOR.EU

Thanks to Franco, Peter and Egil. Best regards to you.
And thanks for more infos via the Internet. Those are ...

I just read an interesting article in Czech ham radio magazine "AMA".
The article itself was about history of the bobtail curtain antenna, but there was an interesting note: Loren Windom first described this antenna, but he himself said that it was invented by someone else as a modification of Hertz antenna.
I found some people to call the coax fed antenna with a balun "FD4" - but some other people call FD4 the modification mentioned by Franco IK1OWB (but the measures are doubled: 9.4+4.7 meters).
73 Jindra OK1FOU

Regarding the Windom, I have a long time experience with such an antenna.
I designed mine in 1978. It is different from the "normal" ones because I use a different type of balun and this, from my point of view, is superior to the toroid one because the core does not saturate with high power or reactive loads.
From my point of view, this type of antenna is not rightly called "Windom", it should be called, probably, Long wire off center fed antenna.
The reason is very simple; the Windom antenna was referenced to ground as the feed point was between an off-center side point and ground.
The modern type of "Windom" Antennas are off center fed but not referred to ground. The validity of calling them Windom is due to the idea of "off-center feed".
73 Gian I7SWX

The windom antenna should never be configurated as an Interted Vee
but should be Flat Top as it was originately.
Matching network such as the Johnson Viking Matchbox is highly recommended
if fed all the way with 300 ohms line.

This antenna is suitable for all traditionnal ham bands.
73 from Cam. VE2SO

O-kay, Definitely maybe, it should not be called "Windom" that is not single-wire fed or flat-top.
But I will call the antenna for multiband "Windom" in high regard.

Well, that is as same as a relation between H-Hentenna and Hentenna. You know Hentenna, don't you? Hentenna is a kind of Loop antenna, but H-Hentenna is not loop.
Anyway, H-Hentenna, that is one of variation of single-wire fed Windom (or 8JK). It was developed by JR1FTE and expanded by JA7KPI in 1982. For more infos, see the LINKs below.