05 March 2012

Getting rid of plasma-tv noise




In my previous post I described the terrible disturbing noise from a plasma hd-tv in the neighbourhood. Today I tried to reduce this noise by using an active magloop antenna for receive only and compare it with a car mounted whip antenna. The magloop is of a commercial military surplus type. It has an in-built HF amplifier which needs 20 V DC supply via the coaxial cable. One advantage with a magloop is that it does not pick up electrostatic noise, e.g. from a plasma tv. When pointed to a transmitting source  better reception can be achieved. I performed the comparison on the 7 MHz band. The result is shown in the video clip below. In the end of this clip you can listen to a pile-up for Kenth, SM7CMV/p in a nature reserve (JO75ak) in southern Sweden, 428 km away from my QTH (JO99bd). I managed to have QSO with him on CW. The car antenna was used for transmit and the magloop for receive. I got 599 and I gave him 559. I used a manual coaxial switch to switch between antennas. I was a little bit afraid of that I possibly would do something wrong so that transmit power (50 W) would pass to the magloop amplifier output. Also if the amplifier would be harmed by the strong near HF field from the car antenna. But nothing of that happened:-)


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1 comment:

Anonymous said...

Jäkla vad vi skrattade.
AM & LE