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.

Friday, December 24, 2010

DIY Magnetic Loop Antenna for UVB-76 frequency (4.625MHz)

Here be finally the drawings for magnetic loop antenna suitable for triangulation and general reception of UVB-76! 
It uses somewhat unorthodox approach for matching the feeder, using coaxial cable shield as a tuned antenna element and internal connector as matching transformer secondary winding, so all the comments and improvements about the design are very welcome!

[edit] Playing around with the antenna (works nice!) tonight, I realized that using the long cable to connect to radio inevitably needs the antenna cable shield teminated with ferrite cores. It means, that you either have to go for a short 1-2m wire to your radio, or you have to find ferrite cores and wrap your antenna cable 5-6 turns around it at the antenna side. Longer cable starts to act as an antenna if no ferrites are added and antenna itself goes nuts as a result.

The PDF with building instructions can be found here.