OTH radars are strategic military equipments that basically allow the operator to “see” beyond the horizon trough the means of ionospheric reflexion that allows HF signals to propagate all over the globe. Regular radars use signals in the GHz regions (better for detection of smaller objects) and are only good for direct visibility, that is why sometimes OTH radars were replaced by more expensive “flying radars” more commonly known as AWACS, but as the Cold War has ended armies are folding back to the cheaper technology and the OTH radard operating in HF are spotted more and more oftenly by amateurs. More details on the OTH Wikipedia page, if you are courious.
Such a signal could be recieved today in Bucharest between 27.480500 MHz and 27.499500 MHz at a S9 level, with a type of pattern I haven’t seen before. Feel free to check out the video and to see how it looks on my SDR transciever.
I’ll try to enter the 8th Spanish Meeting RC Contest that takes place in the first two weekends of May 2012 with the special callsign 233RC103/8SM; i will be my first contest and the purpose is just to gain some experience in these types of traffic conditions.. See you on the air !
I will be running under special callsign 233RC103/QRP whenever the propagation allows it, with only 3W output into either vertical 1/4 GP antenna or testing the new Delta Loop. Working frequencies 27.555 or 27.610 MHz USB.
After a long break of 2 years, i’m back on air as 233RC103, this time making an ambition of using only home-made equipment. And as we are in the 21st century, I have decided classic transciever design is outdated and the future is Software Defined Radio, so I went ahead and started building a SDR transciever, complemented with a home-made external power amplifier and antenna. As I am still testing and developing the new equipment and taking care of problems that obviously come up when constructing such a thing, but I have managed to make a few nice contacts these days: 3AT213, 91RI105, 113RC/DX, 119AT014, 309EX303 are just a few of the many.