8 Jul 2009

SixBox QSO 3 - sensitivity testing

This evening I had a third QSO with G6ALB using the SixBox 6m 50mW AM transceiver. The main aim was to test the receiver sensitivity since fixing an issue last evening. Andrew first called me using his FT817 on the lowest AM power setting and he was good copy. He then switched over to a modulated AM signal generator at 7dBm level (5mW). This was easily copied on the superregen RX. Even with a 10dB pad in at my end I could still copy the signal i.e. at an equivalent of 0.5mW from Andrew 2 miles away. So, without accurate test equipment I can safely assume the RX is detecting low uV level signals. I must work out the path loss.

Having got the SixBox working pretty well it now remains to see how far it can reach. I am really pleased with this simple project. It is very satisfying to work people on AM using really simple homemade equipment built with minimal test equipment and using parts which cost very little.

The current TX frequency is 51.125MHz. I need to buy a crystal for the 6m AM working frequency (50.57MHz in the UK or 50.4MHz in the USA).


g4ilo said...

What frequency is it on, Roger? Not that I'm likely to hear you in north Cumbria, but it might help others who read this and want to listen out for you.

tech said...

Radio Frequency Test Equipment Making useful equipment from low cost materials is a great achievement.