Bob:

Any chance you could download the sweep tone generator (linked in the message above to Petra) and find the sweep frequency setting that you think most likley approximated the type of thing you and your group were "hearing"? (Adjust the seconds interval to show the approximate rate from 3k to 5k,6k ?)

Also, what is the nearest city or lat/long of where your experiments took place?

I'll understand if mum's the word....

2cents

• Bob S.'s response msg w/tone freq. sweep