Friday night activity night

Yesterday evening the first activity period on longwave took place, to encourage Polish radio amateurs with longwave receiving and/or transmitting equipment to meet up "on the air". I think that in Poland only myself and one other guy can transmit on 2190m wavelength. Amateurs' antennas for this wavelength are relatively short and inefficient. So we have to transmit information slowly in a very narrow bandwidth to have any chance of being picked up. As an example, the screen capture shows how my slow morse signal, ( 4 sec dot , 12 sec dash ), was received by another Polish receiving station during this activity period.

Extreme loading coil appears in ham press

A description and picture featuring the massive loading coil I use with my Marconi antenna for 136KHz, have recently appeared in RadCom, the monthly magazine of the Radio Society of Great Britain, RSGB, December 2009, page 29. ( click on the post title to visit the RSGB web site ).
The main winding consists of about 400 turns on a 15cm diameter, 108cm long, sewer pipe and has multiple tapping points. The rotatable variometer winding inside is made from 37 turns on a 11cm diameter plastic water-pipe. The upturned plastic food container on top keeps water out.
The impedance matching network to the 50 Ohm coaxial cable feeder from the transmitter uses an ETD44 transformer core with a 9 turn primary winding and a 20 turn secondary winding. I can obtain a perfect match with this method, though occasionally there is slight detuning of the antenna system owing to environmental effects, requiring readjustment of the variometer.

Award arrives

The award that I mentioned in my last posting has just arrived by post; very colourful it is too. It will look even more impressive when framed and hanging on the wall in my radio room.