Amateur Radio Station I6QON
Osimo, Italy
I6QON WINDOM ANTENNA
The page describes a Windom antenna with a 6:1 homebrew transformer. The feed-point of this type of antennas
(off center) has an impedance of about 300 Ohms. With a 6:1 Balun transformer is possible to feed easily by using a coaxial cable of 50 Ohms (300/6=50), like BROAD-PRO 50 (www.messi.it). In practice, under this condition we have an SWR ratio of 1:1,2 in 80 40 20, in others bands the SWR 1:1,5 it can be easily minimized by
using the antenna tuner.
The antenna works on all bands between 3.5 - 28 MHZ including WARC bands other than 10.1 MHZ. The accepted power with this balun is 1000 W and the SWR is quite low.
One Fair-Rite TPFJ264 green is necessary for the 6:1 Balun. The wire is a high isolation electrical-wire 2,5
mm2.
10 turns on toroid is enough but keep in mind before winding: "cut" the two cables with an equal length.
The "300 Ohms" point of balun is 5 turns.
1 KW BALUN for windom antenna.
The BALUN in the box is that definitive and it has shown good performances (wire black). It also works well with powers of 1KW unlike him anything else other than it had some losses caused by the bad quality of isolation of the electric wire, as shown in photo, the normal wire for electric fittings is not shown proper.
I6QON WINDOM ANTENNA PERFORMANCE
The WINDOM antenna is shown efficente both for the national contact and for the DX'ing with good signals received by the correspondents. The antenna has a good relationship proper signal / noise therefore to the contact to DX'ing. I am very satisfied of its operation.
Bibliography
A Modest 45-Foot DX Vertical for 160, 80, 40 and 30 Meters I6QON's homebrew.
A vertical antenna realized by I6QON, a project drawn by the book "VERTICAL ANTENNA CLASSICS" of the ARRL publications, written by Wayne H. Sandford, Jr., K3EQ.
It is tall 45 (ft) with a capacitive hat of 10 (ft) diameter.
Schematic diagram for the K3EQ 160, 80, 40 and 30 meter vertical antenna.
The circuit for remote band switching.
TOP HAT
TOWER BASE
Insulating the base by I6QON
ABOUT THE MAST CONSTRUCTION
TUNING NETWORK
Commercially manufactured air core coils certanly add a touch of elegance to any homebrew project, but the difference to build with his own hands one of it is a whole other thing.
The original dimensions had to be:
- 7" (178 mm ) length
- 3" (76 mm) dia.
- 6 turns per inch
- NO. 12 wire
B & W coil no. 3033 model, available from Barker and Williamson, 10 Canal St., Bristol, PA 19007
You look as I have realized the same identical core inductores with my hands, with the same original measure of the B & W coil no. 3033.
The final result of the tuning network.
The guy anchors
The figure of side shows an earth screw. There are usually 4 to 6 feet long, I have chosen that from 6 feet long. Under it is illustrated, in theory, as two people installing the anchor. The shaft is tilted so that it will be in the line with the mean angle of all the guys connecting to the anchor.
Earth screw are suitable for use in normal soil where permitted by local building codes.
RADIAL SISTEM
SWR curves for I6QON vertical antenna
