Shortwave “Discone” Antenna, AT&T High Seas Transmitter Site, Ocean Gate, NJ, 2009.
All the pixels, none of the risk of sea sickness, at https://www.flickr.com/photos/mattblaze/4141766569
#photography
Shortwave “Discone” Antenna, AT&T High Seas Transmitter Site, Ocean Gate, NJ, 2009.
All the pixels, none of the risk of sea sickness, at https://www.flickr.com/photos/mattblaze/4141766569
#photography
You’ll notice that each site operated on multiple frequency pairs across the HF spectrum. This was for two reasons. First, each channel could only handle one call at a time, and so this allowed for more simultaneous traffic. Second, not all frequency bands were usable (due to atmospheric and geomagnetic conditions) at any given time. So in practice, at most half a dozen or so ships PER OCEAN could use the system at any moment.
Multiple transmitters shared the antennas using tuned combiners.
@[email protected] I don’t believe there was any attempt to “encrypt” the analog SSB signals either. I remember listening to the conversations which were usually fairly generic and business related. Some of the conversations were from cruise ship passengers who were probably informed the call wasn’t private.
It was much more fun listening to early analog cell phone conversations. People didn’t realize that anyone with a scanner could listen in.
@[email protected] that’s right. Just straight up USB, with regular marine HF radios.