QSL Card courtesy of Paul Greaves (W4FC) 

Many thanks to SRAA contributor, Tom Laskowski, who shares the following recording and notes:

I used to make it a habit to tune to this station just to hear this great Inverval
Signal and sign-on. This usually boomed in on 7255 kHz at sign-on. I have not listened
in years but hope it is still there. I probably logged this on my ICF-2001 back then.

Date of recording: 5/16/1982 

Frequency: 7.255

Starting time: 0530

Location: South Bend, Indiana