DISCLAIMER

DISCLAIMER: I have no association with UVB-76 station, neither do I have any clue what is the content I am relaying. I can only assure, that the signal is received on 4.625MHz AM-modulated 900km NW from supposed origin and retransmitted unaltered. In no way can I guarantee this service, nor be considered responsible of any content re-transmitted. The only purpose for this relay to exist is because lot of people who do not have equipment or are located too far from station seem to be interested about listening to it. Should the UVB-76 station- or transmission content owners feel violated in any way, please contact me at uvb76.repeater@gmail.com and we will work it out.

Note, that because of shortwave radio signal propagation specifics the station can be more or less reliably received from around 4pm to 6am GMT on summertime. It is almost 24h audible during the winter, with short "skip-zone" blank-out around 6pm GMT.

The USB feed is considered as main source of audio today, as the voice messages are much better audible there than on the AM stream. However, the buzzer sound from the AM stream is somewhat more pleasant to listen at, so both feeds are kept simultaneously.

Thursday, June 17, 2010

New Antenna!

This listening post has been much more popular than I could have ever expected. So far it has been grat educational project of how to create a Internet Radio, but it has also given a good reason to spend much more time on the project! So, for two days now, the scanner has been equipped with nice 140cm diameter Magnetic Resonance Loop antenna.

For those initiated, some words about it below:

The radio was initially equipped with just a 10meters long aerial. It had some coupling (3meter long wire for counterweight, for example etc.), but did not have any tuning. Neither wa sit with any sufficient length. As the frequency we are receiveing is 4.625MHz, it will make the wavelength of 71m, which makes any decent antenna on that frequency at least 71/2=35.5 meters long.

The other problem was noise. The signal received was not that bad, but it was overcrowded with all sorts of urban noise (worst of it radiating from plasma TV back to the mains cord!).
I spent about a week with my three shortwave antenna books, and finally decided to give a try on magnetic loop, before I start climbing on the neighbours roof.

The result - two nights of building and ... the result is really amazing. It is not that much more sensitive han the long wire was, but it has two stunning propoerties: First - it has almost no noise, as it is tuned to exactly the right frequency. Second -it has excellent directional characteristics. Which is of course why these types of antennas were used for directinal radio navigation for ships and military all the way until mid-80s.

I will post the details for the antenna here later. This antenna is not suitable for random shortwave hopping, as you have to tune it and turn it for the exact bearing and frequency to make it work.
However, if you know the frequency and know what direction it is, I would definitely recommend building one! I can not imagine anything else for 80m band fitting in your room and giving even remotely the same result!

1 comment:

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    trung tâm ngoại ngữcủa Yêu Huyên cũng chỉ có thể miễn cưỡng chống lại mà thôi.

    - Yêu Huyên gây nên địa kiếp này thật là mạnh mẽ.

    Nhạc Thành thở ra một hơi, bây giờ địa kiếp xung quanh đã tràn ngập một khí tức cường hãn rồi.

    - Rốt cuộc cũng đã xong.

    Dưới địa kiếp không ngừng này, Yêu Cơ, Khiếu Thiên Hổ, Tứ Sí Ma Ưng Tử Điện Mãng tựa hồ như đang ở giai đoạn cuối.

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