Lots of HAMs are not allowed to install a standard antenna. Some German QRPers designed the KGD, thats a German nickname for a very short dipol, that can help this friends because its realy small but very efficient.
On 40 meter the KGD is only about 150cm long. The Dipol is made from 20mm Aluminium tube and two 18mm diameter coils.
The middle part of the KGD is made from polyamid. The coils are made from 0,8 mm enamelded wire. To convert the 50 OHM cable imppedance, we use a capacitor rated at 6 kV
At both ends of the KGD we use short Tuning Rods. Tuning is very reproducible. We tested 10 KGD at 40m and found them all within +/- 5 kHz at the same frequency. Bandwith for VSWR 2 is about 45 kHz at 40m
We use RG58 cable to feed the KGD. Our special mast to antenna holder is designed to enable horizontal or vertical mounting at a fishing pole. If the KGD is used verticaly, the coax must follow a 90 degree angel at least for 1 Meter.
The QRPproject KGD is limited for 100 Watt RF power maximum
We ship KGD kits from stock. The coils are allready wound and the Cap is installed. You only have to install the tubes and the coax cables.
Take care that now one can touch the KGD during transmit. Even with 5 Watt there are extreme high Voltages at the dipole.
The KGD is not longer available
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