This is shaping up to be another winter that never happened. So long as you don’t count that arctic blast with less than two-inches of snow in the few days leading up to Christmas. These gloomy, depressing, days of 38F and light rain get old. They also keep me indoors and looking for ways to pass the time without endless napping. The quest for FT8WW in the log has been fruitless and I’m bored with radio at the moment.

I was catching up on some reading that’s been stacking up over hot coffee this morning when I came across an interesting book review in the December 2022 edition of the Gray Line Report, the Twin Cities DX Association newsletter. The TCDXA book review was provided by Mike Cizek, W0VTT.

'The US Navy’s On the Roof Gang' was written by Matt Zullo, CTICM, U.S.N. (retired).

There are actually a couple of books (Vol 1 & 2) covering the discovery of Japanese katakana code being sent via continuous wave shortly after the end of the First World War. It begins with a radio amateur, Harry Kidder, PI1HK, a Navy radioman stationed in the Philippines who was possibly the first to copy CW signals that weren’t quite like the Morse he was used to receiving. Eventually, he determined that he was copying Japanese Navy transmissions.

This put the Navy on a long path to making signal intelligence a real thing.

This was the 1920’s and while the US wasn’t at war, the burgeoning field of radio was becoming better recognized as a mechanism of war. Once the Japanese code had been cracked the Navy set up a training station for other radiomen (and women) in a cinder block building on the roof of the main Navy building in downtown Washington, DC. Thus the moniker, “On the Roof Gang”.

Over the next decade multiple intercept receiving stations were setup across the Pacific. Using HF direction finding techniques the Navy got pretty good at snagging these signals and determining their points of origin. These intercepts were then forwarded to Washington for decoding and analysis.

By the time the Japanese attacked Pearl Harbor in 1941 the US Navy had assembled a network of radio intelligence that would become useful during World War Two. (pity it didn’t prevent Pearl Harbor - or did we know about the attack ahead of time?). While the work at Bletchley Park and how that impacted the War in Europe is well known, personally, I’ve been clueless until this morning about the use of radio signal intelligence in the Pacific and its impact on the war.

The review also included a link to an interesting video from the WW2TV channel on YouTube (who knew that was a thing?) with a nearly 90 minute author interview. I enjoyed it so much I bought the two books and look forward to devouring those and taking a deeper dive on that World War Two YouTube channel.