Thanks Token for coming to my rescue last time - here's another one that doesn't bear any resemblance to anything on SigIDWiki: Every few minutes on 6961 kHz last night I observed two identical bursts in short succession of what appears to be a very brief 24 (?) tone signal. Audio at
http://www.lutins.org/temp/6961.mp3 and waterfall at
http://www.lutins.org/temp/6961.jpg. Thanks again in advance for your expertise!