Hamradio.in

Moxon Rectangle Antenna for TV

N. S. Harisankar - VU3NSH

May 12, 2013

This antenna is much useful for city dwellers for mounting at balcony, sunshade or windows to receive the local TV station very clearly, like getting the gain from a four element yagi antenna. This is the continuation of the experiments on Moxon Rectangle Antennae. Previously one of this antenna for FM Radio Broadcast - 3 meter band - was published in hamradio.in (FM Radio Rectangle Super Gainer).

Now the experiment and test is conducted for 1.45 meter band. ie. the Palakkad Doordharsan TV Channel 9 frequency. I made this antenna with 4 mm brass rods and plexi glass spacers and mount. By using proper machining on plexi glass rods the critical spacing of the two element’s edges are made perfectly. After completing the antenna the test was done at the QTH of SWL Rejeesh. The TV relay station channel 9 is 4 kms away from his location and it is LPT (Low Power Transmitter). When the first test was conducted at his roof top, when rotating the antenna, we cannot find the directivity like yagi antenna and we got clear pictures from LPT with the orientation of more than 80 degrees !!!. This is due to its wide angle character and it is 136 degrees typically. So we decided to down the antenna to floor level and brought inside the home to make test by reducing the natural receiving signal level to the antenna from LPT. From this low level test, inside the room, the signal level drastically reduced due to the attenuation of surrounding objects and very low height also. In this condition, we got 80° span (40° + 40°) with a clear picture. After this directivity test we decided to turn the antenna into 180° (back of the antenna) and we observed the signal level is very weak with lot of grains. Finally we assured the forward gain of this antenna once more.

The connectors used for this antenna is F type cable TV connector and connected with RG 59 Coaxial to the TV without a balun transformer. The following photos and sketches will help you for making this antenna very easily. Enjoy a good TV reception with minimum materials.

Fig. 1. Moxon channel 9 TV antenna - diagram & measurements
Fig. 1. Moxon channel 9 TV antenna - diagram & measurements