Ham-radio-Triband end-fed half wave antenna for portable use. By Peter VK3YE

Ham-radio-Triband end-fed half-wave antenna for portable use. By Peter VK3YE





Ham-radio-Triband end-fed half-wave antenna for portable use. By Peter VK3YE. There are many variations on the end fed matching network and this is an interesting design by Peter VK3YE who I am indebted to for sharing this video it shows how you can simply make a matching circuit, its fun and cheaper than buying one.

I use a play on the theme by using a T240-43 toroid wound with 24 turns on the secondary side and three on the primary winding I am not quite sure what Peter uses in terms of enameled copper wire but I used 1.18mm wire for my transformer.

The end of a half-wave aerial is the voltage maximum on a half-wave radiator with a high impedance of several thousand ohms.

The ratio of 24 divided by 3 is 8.  8 squared is 64 x 50ohms = 3200 ohms, this circuit matches down to eighty meters, maybe it will do 160 meters if I use a couple of ferrite rings stacked on top of each other.

With 27 turns of wire and 3 on the primary, you have a bigger ratio of  9:1 using the calculation above, 9x9 =81 x 50 = 4050 ohms which you may need depending on the wire used for your radiator, this design does not need any type of counterpoise and it is interesting to see Peter adding a loading coil for 40-meter operation.

"EFHW" - the end-fed half-wave antenna

http://pa-11019.blogspot.com/2012/04/149-transformer-for-endfed-antennas-35.html






Ham-radio-Triband end-fed half-wave antenna for portable use. By Peter VK3YE

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