Amateur Radio

Hi @Sigord

Yes you could use the antenna for transmitting as well but then rather use a 50 ohm coax (RG 174) or similar.
RG-11 or 213 cable is even better but quite unwieldy to handle.

You should also check the SWR.
Matching can be done by making the elements slightly longer than calculated, then trimmed in small decrements by snipping off pieces of the brazing rod with heavy duty pliers.

The angle at which the ground radials/elements slope down at can also be adjusted (simply by bending by hand) to further optimize the antenna's match to the transceiver.

Although the antenna has a theoretical gain of 0dBi, in practice you will get a vast improvement in range as rubber duck type antennas typically have up to 10dB of loss, so the improvement will be 10dB less the attenuation in the coax cable.

You of course also have the added benefit of not having all that RF being radiated in close proximity to your body and head.

For 446 MHz (as shown on the FT-60's screen), the elements will have a length of 160mm, so make them around 165 - 170 mm and then trim whilst watching the SWR meter.

 

Don't forget to water proof the center element as if left exposed, the antennas impedance will change every time it rains as water will create a partial short between the center and ground.

Avoid glues, silicons or epoxies that contain high concentrations of acetic acid as this will attack and corrode certain metals when in contact with them.

Keep the amount of "goo" (to water proof the hole where the cap slips over the center element) to a minimum (a small percentage of the wavelength) whilst still maintaining a good seal as it will have an effect on the loss and velocity factor especially at UHF and higher.