I didn't build my K2 (I wish had!), so I have limited experience of its alignment.
Having finally got around to getting back on psk31, I have noticed a banding effect in the waterfall - both with mixw on the pc and cocoamodem on the mac. Removing the audio feed from the K2 shows the usual digital artifacts often observed with integrated soundcards in particular, but no evidence of any ripple. I'm using the inbuilt sound on a new Intel mac mini running both Leopard and XP. I don't believe the computer is to blame. Anyway, as noted below, the OP1 filter shows none of this. Running spectrogram with random noise at the antenna (not much else on 12m, four hours after dark!), I can see a distinct ripple in the passband of all filter widths, in every mode. Except, that the OP1 filter in the ssb board gives a flat response in all modes. So it's something to do I guess with the setup of the variable crystal filter. I am wondering how far back I will need to go in the setting up of the K2 to find the adjustment which will perhaps flatten the shape. Using spectrogram (latest) with the xtal filter in usb at 2.1kHz, there is about 10dB between peak and trough of the ripple. The peaks are roughly 600Hz apart. I'd never noticed this in casual listening, I doubt that I could have done. Most of the time I am on cw and the 700Hz filter setting shows no obvious ripple anyway. It does however certainly not look right on the waterfall on psk31! I'd be grateful for any advice! Thanks, Stephen G4SJP _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
