In response to our second mystery interval signal challenge, SWLing Post contributor, Dean Bianco replies:
This is the “interval signal” (more accurately, a placeholder with a musical station identifier) for the Compañía Telefónica Nacional de España (CTNW) from Madrid, Spain.
They were a point-to-point HF radiotelephone terminal that provided overseas telephone and telegraph services in the days before satellites became common.
As a young SWL, I would receive all manner of strange musical identifiers for these utility stations. Most of these HF telecommunication services had gone to satellite by the early 1980’s. The HF bands were chock-a-block with signals, whether they be broadcast or utility services.
Glad to help!
To verify his claim, Dean shares the following embedded audio file made by Willi Passmann in the mid 1970s (via the excellent UtilityRadio.com website):
Well done, Dean! Thank you once again for coming to the rescue!
In case you didn’t know, dear readers, Dean Bianco is a force to be reckoned with in the shortwave radio world. 🙂 This year, he won the 3rd Annual Fest Trivia Quiz at the 2020 Winter SWL Fest! An impressive accomplishment, indeed. Not only that, but Dean’s an incredibly nice guy, great friend, and always willing to help out those new to the hobby!
Thank you, Dean!