Sunday, 15 December 2013

1.2 GHz biquad antenna ready

Today I finished the biquad antenna. It is a lightweight version of another biquad I used before. This evening I fixed the antenna onto roof. 
Opening the attic window to stick the antenna outside is not necessary anymore which is good since winter temperatures are approaching.

             Here you see the antenna with a bunch of RG6/U coaxial cable (10 meters)

                                                         This is how I started

To make the antenna moisture proof a transparant box was glued over the element

Antennas on the roof. In front LNB for 10 GHz RX in the back the 23 cm biquad for TX

The antenna is connected to the ATV transmitter via 10 meters of coaxial cable. I intended to buy hi frequency low loss 50 ohms coax like H100 or Aeroflex. But the prices of this type is rather high. About 4 euro's each meter. In the "Praxis" they sell RG6/U  75 ohms coaxial cable for regular satellite receiver use. A bunch of 10 meters sells for 10 euro's. I thought the difference between 50 and 75 ohms is not that much (SWR of 1:1.5 and reflected power is only 4%). This appeared to be true. My ATV signal is copied in good quality by the repeater. The specifications show that the attenuation of 10 meters RG6/U is approximately 2.5 dB at 1.2 gigahertz . Not that bad.

You can find the dimensions of the antenna in my blog article of September 2013.

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