some more tests :
After that, test of the Si570 frequency control with the USB to I2C interface : The bench test.
at the QSE testin point…
… and on the computer. The local oscillator is 4 times the working frequency : so far, so good.
After some scope measurements and signal tracing on the MoBo (and after adding a dip switch to control the band switching), the receiver is up and running.
I lost 1 day looking for a receiver problem : nothing was comming out on the I/Q plug, and the audio card was giving a flat EEG. Nothing on the scope, transformers were tested again, the mixer was mixing….
… but I didn’t realised that I plugged the I/Q output of the Softrock on one of the souncard output… and not an input. After changing the plugging, everything was working fine again.
The gods of ham radio exist… it’s contest day today. CW everywhere!
The ugly stuff in a plastic bag is the isolation stage between audio ouput and the sound card (an Edirol FA-66) : a couple of Triad SP69 600/600 Ohms transformers.
Right now, the transmission is…half working. Signal is running thru the MoBo to the 2N2222, but I do not have any power at all. Probably a stupid cabling mistake of a failed component on the final stage. Controled on my TS50S tranceiver, transmission is working perfectly and the transmited signal is on the good frequency.
I’ll check this later.