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Created on :
2002-08-10
Frequency band :
23cm








































A 23 elements 23cm yagi antenna






The story

I have been looking around for antennas for a while for 23cm ATV reception. Everywhere I go, the prices are the same : far too high for me. The more elements you want, the higher the price of the antenna.
But than I saw Paul (PA0SON) walking with a nice and shiny 23 elements Tonna antenna. The design of the antenna is very straight forward. It's a boom made of aluminium with the elements 'floating' above it on plastic isolators.
I decided to try and rebuild the antenna using a PVC-tube to hold the elements. The elements I made of copper wire. In total this antenna cost me about 4 Euro. So for people with only a small hobby-budget this is a perfect project :)



The size of the elements

Element name Distance to the end of the boom (in cm) Length of the element (in cm)
Reflector1,611,5
Driving element5,1* (see text)
Director 17,69,9
Director 211,09,6
Director 317,59,5
Director 424,39,4
Director 531,09,3
Director 639,19,2
Director 748,09,1
Director 857,19,0
Director 966,19,0
Director 1075,19,0
Director 1184,19,0
Director 1293,19,0
Director 13102,19,0
Director 14111,29,0
Director 15120,29,0
Director 16129,19,0
Director 17138,29,0
Director 18147,29,0
Director 19156,29,0
Director 20165,29,0
Director 21172,69,0


All elements are placed 4,2 cm above the boom except for the driving element. All elements have a 3mm diameter.
The measures of the driving element are shown in the following picture :


I could not see how the driving element of the Tonna antenna is connected to the coax cable, because the element is one big block of plastic. I connected the cable as shown in the following picture. It works very well, but maybe there is a better way of matching the transmitter to the dipole...




Some images of the antenna :

(click to enlarge)



- Created by Daan Vreeken - PA4DAN -


Email me with questions/comments : Daan <Daan @ pa4dan . nl>