Hi, sorry for not posting for long. Guess what? I got my hands on a 12 element Yagi antenna used for TV reception.
I was at Mr Jeff’s lab testing out the transmit performance of a TV Yagi antenna when compared to a Yagi antenna made for the amateur radio bands. The antenna didn’t have a proper connector so we just used a few crocodile clips to connect it to the antenna analyzer.
This is the performance of the antenna when connected up to antenna analyzer. Note that this configuration is mismatched as we connected a cable of about 50 ohms impedance to a 75 ohms impedance antenna.
I am really surprised by the results! For the 70 centimeter band, the SWR of the antenna is around 1.8 to 2. Even for the 2 meter band, the SWR of the antenna is around 2.6. Some tuning and matching would make it better! :)Now, let us compare our results to a Yagi antenna built specifically for the 70 centimeter and 2 meter bands. This is the antenna itself.
Of course, you get what you pay for! Mr Jeff’s antenna has an SWR of 1.23 for the 2 meter band and 1.04 for the 70 centimeter band. But hey! For a S$30 TV Yagi antenna, as compared to a S$170 dual band antenna, its performance is really not bad!It was fun learning working with antennas, I’ll see whether I can tune and match the TV antenna to get the maximum efficiency possible, that is, if I have the time! 😛