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It's not the Navy's fault.

IIRC, the garage door companies used a heretofore little used frequency allocated to the military.

Guess what happens when the military starts using their allocated frequencies?

Oh, you already know...

I don't think that was it. The Navy was very hush-hush, and adamantly denied it was them. There was a lot of testing of communications technology going on around that time, and a sub base, a Navy base, and a Marine air base nearby where interference could have been coming from. If the garage door companies were at fault, it would have been easy to say that. Also, it would not be intermittent, but all the time.

I don't think that was the explanation.

Don't get me wrong, I don't care that the Navy interfered with our garage doors. I'll pay the price of getting out of the car to defend our freedom. Nor do I think they had to tell us if they were. If it was some ELF program or something else, no need to shout it out to the world. It was just part of living in Pt. Loma.

I wonder if it still happens.

IIRC, the garage door companies used a heretofore little used frequency allocated to the military. Guess what happens when the military starts using their allocated frequencies?

Garage Door and Vehicle RKE (Remote Keyless Entry) uses a center frequency of 315 MHz. They may be moving to higher frequencies (915 MHz) and more interference resistant technologies (spread spectrum frequency hopping instead of just once frequency) themselves, but many are still relatively simple transmitters and receivers centered around the 315 MHz frequency.

If I recall correctly, the Military UHF band is 225-400 MHz. In my day (late '70s) it was single frequencies changed every day, and voice AM (Amplitude Modulation).

Now with the more modern times and more sophisticated electronics / computer controlled everything, I believe the Navy, ands probably other brances of the military as well, are using a spread spectrum system - not any one frequency, just frequency hopping along all across the band to a certain synchronized pattern changed every day. Impossible to eavesdrop and near impossible to jam.

But it does "raise the noise floor" if you hook a Radio Frequency Spectrum Analyzer set up for "Max Hold" Display Mode" up to a broad band antenna. Also can swamp out / desensitize broadband receivers.