Dean solves second interval signal mystery

[IB4TL]

In response to our second mystery interval signal challenge, SWLing Post contributor, Dean Bianco replies: Mystery solved! 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 […]