G15 was a part of BND's extensive number station network. This one always transmitted on four frequencies simultaneously - 2707, 5015, 7404, 11108 kHz - eight times a day, every single day of the year, at 00:00, 00:30, 06:00, 06:30, 12:00, 12:30, 18:00 and 18:30 UTC. The :00 transmissions were the primary sendings done in AM mode, and the :30's - repeats done in USB mode.

The G15 designator refers to the newer format of this station, which involves automated voice and is essentially identical to G14 and G16. Refer to G15a for the old format.

Unlike all the other G16 stations, G15 had a very large number of recipients, but all received very short messages. The messages sent were rotating throughout the week, as presented below: (the 3 digits are the ID, the one or two digits afterwards - the amount of groups)

G15 was generally very stable in operation, with transmissions always starting right on time with very few mistakes made during them. On one occasion, the sister station G14 was noted being sent on the four frequencies of G15, rather than on its own, instead of G15.

Details on encryption and decryption of G15 messages can be found in this declassified Polish counter-intelligence document.

List of ID's used by G15:

[Based on Simon Mason's 1991 book Secret Signals]

[ID's from Numbers & Oddities #58]