Of magnetic interest?

system.

In 1950, I worked at Bell Labs at Holmdel on an experimental set-up for this system. We used six-inch copper pipes at X-band to simulate the future two-inch guides at a higher frequency. Most of the work was on launchers to produce the required TEzero mode required for low loss.

No Long-Lines transport was over "multiple coaxial cables" any more than a viewer needed a red set of rabbit ears, a green one & a blue one. (That said, L4/5 used "Coax 20" cable with 9 tubes east, 9 west, & 2 hot-standby; L3 used Coax 8. In both cases, each working tube was distinct from its neighbors.)

L3, the 1953 tube-type predecessor to L4 could carry TVS with some limits.

The L3 Coaxial System: Television Terminals

From someone who worked on same:

"they placed a vestigial sideband TV signal on a 4.1 MHz subcarrier in the vacant bandwidth above telephone mastergroup one."

"The advantage of TV on {4 Ghz microwave} TD-2 {vs coax} was that the IF could be bridged-off at any repeater along the route without disturbing the through-path."

You still don't get it. NTSC COLOR VIDEO WOULD BE CRAP AFTER ONE HOP ON THAT VOICE BASED SYSTEM. THE RGB REFERENCE WAS VIDEO CABLING INSIDE A TV STUDIO. Even as FM video, the errors are cumulative. TV stations had a pair of coaxial cables from the nearest terminal so they could both send & receive video from the network. They also had lines between sporting arenas and the nearest terminal to be able to carry events live. The second cable was used to feed the preview video back to the remote feed site to keep them on time to switch in and out of network.

The biggest advantage was that the passband ripple was low enough not to

Hell, I still have MY hp 70 MHz test sets for microwave relay sites. I built Telemetry equipment with 70 MHz IFs, and some of the units sold for $80,000. TV STL uses 70 MHz IFs, and old Cband Sat recievers used 70 MHz. "3702B IF/BB Receiver W/ 3705A Diff Phase Detector" i don't remember the transmit side model number, and I'm not going out to the shop in the dark.

read

competitor. I

It turns out that i was trying to remember MCI. The history on wikipedia reads different today than that i remember.

?-)

It was not "voice based" until you got down to the channel bank level. (Here's a good write-on on such

for those interested.) When used for TVS, the previous link on L3 TV ops is a good place to start reading.

And as a system, it was such "CRAP" that the networks paid LARGE sums of money to Long-Lines on a daily business, for 25 plus years. Now, that big a customer could have been making a stink, demanding alternatives, and whatever else.....instead of just paying. But the record does not support they did that.

Now there certainly downsides to Ma's 5+ decades-long focus on FDM systems. One was, when DS1 over T1 starting really rolling out in the mid-late 1060's; many transmission folks at the operating companies {& LL as well, I'd bet..} resisted such, since it was unfamiliar. A friend retired from such a Transmission Engineering slot told stories of battles over replacing N with T.

They paid because CRAP was the only game in town, other than the 'Bicycle Network' like AFRTS used. TV network feed was a mix of coax & microwave, since ATT microwave towers weren't at the studio sites. That required coax between the station and the nearest microwave site. As a former Radio & TV broadcast engineer, I consider the feed quality crap, when compared to what replaced it. Network video in the 50' through the '70s was muddy. Absolutely unacceptable by today's standards. Early video tape was not much better, when used for color. That's why Kinescope was still in use in the '70s, until better machines and magnetics were developed. Most stations maintained & used 16 mm film chains for the majority of their programming. One station I worked at was all film, or live.

As far as demanding alternatives, they went to C-band, then KU band network feeds and microwave STL and backhaul feeds. I'm sure that you've seen a ENG van with the telescoping mast & microwave antenna. In the early '80s a mobile sat uplink cost well over a million dollars to purchase which put it out of range for all but the biggest stations, but for $20,000 they could throw up a couple 5 meter dishes and buy a half dozen C band receivers. That was the end of ATT's monopoly on network feeds.

You're familiar with EPG, (Electronic Program Guide) on cable TV? It was owned by United Video in the '80s. The VAX computers were in St. Louis, and a pair of leased phone lines linked it to Chicago, where it was transmitted as a subcarrier on our WGN uplink. Those two lines were

Unlike radio, a leased phone line just wouldn't do. Some network radio feeds were via shortwave feeds or simply by picking up another station on the network. At one point, the VOA had a private microwave network from Washington D. C. to their 'Bethany' Plant in Mason Ohio. 'Bethany' was the VOA's secondary master control for the network, in case something happened to the main control center.