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.

'pip' Feed is Back

Apparently, as the voice transmissions are more routine on UVB-76 frequency these days, another Russian number station, the 'pip', has also woken up and started talking on 3.756MHz nighttime / 5.448MHz daytime.

Danix111 has caught one of the messages, please check at http://danix111.cba.pl/ns/the-pip-message-021210-2010-utc-cleared.mp3

 

Therefore the 'pip' feed is now put back on air from the repeater, please check the link on top of the page.

Please note tho, that it is using the testing feed of the repeater and is aired from my auxiliary scanner (Icom R-20 as always), so it will not be as stable broadcast as other feeds because time to time I will use the scanner and the feed for other purposes. However, if nothing else is going on, I will keep 'pip' on 3.756MHz running. This also means that as I dont have automatic frequency switchover, the feed is silent daytime, when its transmitted on 5.448MHz.

Triangulation Call!

There has been an ongoing debate about the location of the UVB-76 transmitter. Many pictures have been posted on .ru forums about the buildings in Povarovo what suggest the station is not located there any more.

Therefore, I will call everybody with the SW receiver in their hands to post the direction to the signal from their location to the uvb76.repeater gmail address (as found in contact details of this blog page).

Please mark down the following details:

• Your location (coordinates are the best, give as precisely as you dare), but country and city/village will do as well.
• Bearing of the received the signal. 0 degrees means exactly to the north, 90degrees means exactly in the east etc. and clockwise from there on. 
• Time you did the triangulation. As atmospheric conditions change and most of you will be getting the signal from the strathosphere reflection rather than direct, I would suggest doing it several times at different (night)times.
• Signal strenght. If you do not have S-meter, just describe it in plain english (barely audible .. ok .. strong .. very strong ... etc.).
• [edit] For sake of general interest, please also describe the gear and antenna used, it will be interesting to see what everybody are using out there.

I will collect the data and will put it on the map. I will NOT publish it before I have gotten enough data so it corellates to some specific spot, so given the relatively low precision we are getting here, it will take about 5 submissions before it starts making sense.

For those wanting to build a magnetic loop antenna for getting the direction exact, I will publish a drawings of my magnetic loop antenna in next couple of days.