The blog of a dedicated radio amateur and electronics enthusiast

"Having fun on the air and in the workshop - communicating and creating"

23 August 2011

New antenna radiates

The new antenna for longwave, mentioned last time, radiates. I have been making some test transmissions on 137.7KHz and these transmissions have been received by Jacek, callsign SQ5BPF, on the other side of Warsaw. The screen capture below shows how he saw my signal on his 'lf grabber'. Incidentally, he could also hear it.
So now I have a reference signal with which to compare future signals as I make improvements to the antenna installation; the aim being to make the signal stronger and the signal trace white rather than the orange colour it is now. Losses in the system have to be reduced. To achieve this, I shall start by burying more copper in the garden. This will be a very labour intensive and time consuming activity. I shall probably be eaten alive by mosquitos before completion ! I hope to report total success in the near future - if I survive the ordeal.

12 August 2011

Wire in the sky


I have erected a new antenna in readiness for the restart of my radio activity on the 136KHz 2190m longwave band during the coming autumn and winter season; simply a 45.9m long wire, and a number of bare copper conductors buried in the ground directly below. The wire is supported at the mid point by a fibreglass pole, and a spring counter-weight ( see inset ) running through a pulley tied at the highest point I could reach to a tree at the far end.
The (in)famous loading coil, ( posts dated Feb 19th & Sept 13th 2010 ), will still have to be pressed into service; but fortunately it will be installed inside my radio room. What a huge relief that I will no longer have to use the coil outdoors or carry out frequent maintenance on it inspite of the snow and ice, as with the previous antenna !
My last attempt to put up a different antenna for long wave was in 2009. It was a much more complex design, both electrically and mechanically, requiring 'miles' of wire. It would have been an excellent performer. Sadly it never came to fruition, being blown down / away four times during summer thunder storms before I had even finished building it. There was an important lesson to be learnt from that ! It's better to have a simple antenna than no antenna.
While the performance of the new antenna will be inferior to the one I didn't complete, it should out-perform the last operational one.