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40M band closed ?
wrote:
I have another doubt. A 11KV power line is running some 20 feet away from my antenna. My doubt is whether this power line may be responsible for the QRN? That's VERY possible. High-voltage lines like that tend to be pretty noisy. On the other hand, while it could certainly cause noise for you, it shouldn't cause noise elsewhere in the city - other hams shouldn't have problems. I wonder if maybe a shortwave broadcasting transmitter, especially one on the 41m band, has a fault and is radiating spurious noise? If the noise is that strong, I would think such a fault could be heard elsewhere in India, maybe within 400km or so during the day and quite a bit further at night. The recent VU4 Andaman expedition didn't mention anything like that though, and I'd think it *would* be audible on VU4 at night if it was that loud. Do you have the capability of listening on other frequency bands? Is this noise present in the 49m (6MHz) shortwave broadcasting band? In the 80m (3.5MHz) and/or 20m (14MHz) ham bands? How about in the MW broadcasting band? Or on TV? (assuming you're using analog terrestrial over-the-air reception) -- Doug Smith W9WI Pleasant View (Nashville), TN EM66 http://www.w9wi.com |
#3
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40M band closed ?
Thanks to Mike and Doug for a detailed answer and thanks for your time.
Doug Smith W9WI wrote: That's VERY possible. High-voltage lines like that tend to be pretty noisy. Yesterday evening at around 8PM IST(-5.5hrs GMT), i took my receiver to a different location some 250meters away from my QTH and hung a wire antenna and switched on the receiver and there was no noise . All the broadcast stations were crystal clear and since Indian activity ceases after 6PM in 40 m band, i didnt receive any Ham signals. Nevertheless change of location proved that the noise is generated from somewhere nearby my house. An interesting news is that the new location is situated on a busy main road where the traffic is heavy. So, as Mike suspected, the noise may not be from OTH radar. On the other hand, while it could certainly cause noise for you, it shouldn't cause noise elsewhere in the city - other hams shouldn't have problems. The problems other HAMS are facing may be due to the skip distance involved as Doug told yesterday. They are not able to have local (250KM radius) QSOs. Do you have the capability of listening on other frequency bands? Is this noise present in the 49m (6MHz) shortwave broadcasting band? In the 80m (3.5MHz) and/or 20m (14MHz) ham bands? How about in the MW broadcasting band? Or on TV? (assuming you're using analog terrestrial over-the-air reception) My receiver is designed for 40m band, since i am much more familiar with that band when compared to other amateur bands. In future, i may add other bands to my receiver. Another experiment : I used to keep my receiver in the first floor room. Today morning i brought the receiver down and hung a wire antenna around the house (indoors). A part of the antenna wire, some 10 feet, was on the floor and the rest of the antenna, some 25 feet where above the ground at around 7 feet. The noise was present. When i lifted the part which was lying on the floor, the noise dipped to a very low level. The higher the antenna was lifted from the floor, the lower the noise level. But i was not able to receive any broadcast stations, like i used to receive when i kept the receiver upstairs. I have some other experiments in mind and I will post the results of the experiments, when they are done, to this group. Regards Shan |
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