Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N7WR, Jan 2, 2019.
Heck, that's nothing---you should see the antennas we grow down here in Texas!
In 1989, the US completed an Extremely Low Frequency (ELF) antenna in northern Wisconsin called Project ELF, also for the purpose of submarine communication. It was 84 miles long (135 km). According to below article, at its operational frequency (76 Hz), it took 15 minutes to transmit a 3 letter code using a pair of linked transmitters consuming 2.6 megawatts. Certainly not "real-time" communication! It was shut down in 2004.
It operated 24 hours per day so subs could determine if they were within receiving distance (about 1/2 of the earth). I recall my brother-in-law (a civil engineer) worked on the construction site while it was being built. Actually, I didn't realize it was shut down until searching for background details to write this post.
Interestingly, there was an attempt to put the antenna in the Texas Llano Uplift, but Texans didn't want it. Too small, I suppose!
Nice, I love QRP operating!
Ah, yes, the good ol' 4,000,000m band...
I thot subs were sandwiches---
TOM K8ERV Montrose Colo