Ham Radio Forum

Hello Everyone,
As I am new to Antennas and only started learning about them to design TV antennas for a selected frequencies only.
This is due to me being far away from the TV station as I live in the country about 90km's from the transmitter I want to receive.
Basically 4 stations are in the bands 170MHZ to 226.5MHZ and 1 is at 536MHZ.
I built a 2000mm long yagi for the lower bands and it only picked up 2 stations.
I also built a 2100mm long yagi to pickup the 536MHZ station with it didn't.
I got the design of a "WEB log in" site that allows you to enter all required info and it gives you the sizes etc to build the yagi you desire.

My question is that all though it didn't pickup the station at 538MHZ it did pickup 2 of the stations in the 170MHZ to 226.5MHZ range and showed signs of pickup up the other 2 stations?
I changed the "Driver" dipole to the length specified in the WEB program for the 170MHZ to 226.5MHZ range as well as the reflector and I got 3 stations. I tried changing a few other elements but found that with fine tuning of the "Driver" and "Reflector" I now have all 4 stations.
Why is this so?
Is it because there are more "Director" elements on the boom for it length due to the shorter elements and their spacings.
The size of the 538MHZ elements are 260mm long tapering down to 215mm and the size for the Driver dipole is 2 X 350mm. The reflector element is 660mm long I am not using a folded Dipole.
The signal is being feed from the antenna dipoles through a TV Balun.

Multi-element antenna sensitivities to various frequencies vary in complex ways as element lengths and spacings are adjusted. It would be necessary to model the antenna exactly as you have it now to be able to answer your question.

Ryon