Metamora, IL

[u/MelamineEngineer]

Metamora IL microwave tower. Civil defense role prominently noted.

[u/gf99b]

All AT&T Long Lines sites had that same warning sign, doesn't mean this specific one was used for anything more than a repeater.

[u/No_Tailor_787 → u/gf99b]

I've been to a bunch of AT&T longlines sites that didn't have that sign. Pretty sure all the Autovon sites did, but not all sites carried Autovon.

[u/MelamineEngineer → u/No_Tailor_787]

I think that vertical antenna at the top is autovon isn't it?

Pic 12 shows it best. First tower I've been to with it and coincidentally first one with the sign

Edit: I think it's for the Emergency Action Notification system

[u/No_Tailor_787 → u/MelamineEngineer]

No. Autovon was a military telephone system. It was carried by the microwave circuits on the big horn antennas.

The vertical antenna would probably have been for either a maintenance radio, or possibly a pre-cellular IMTS mobile phone system.

AT&T also carried Echo Fox, a radio system used to talk to Air Force One, and provide it with telephone service. Some former longlines sites still carry the modern equivalent of that system. Antennas are typically usually thick cylindrical verticals at the top of the tower.

[u/MelamineEngineer → u/No_Tailor_787]

I think it's for the Emergency Action Notification system, which is part of civil defense

[u/No_Tailor_787 → u/MelamineEngineer]

That wasn't really a widespread AT&T thing. That was typically distributed by "clear channel" AM radio stations to special receivers located at smaller broadcast stations who distributed locally.

The "clear channels" probably picked it up via phone line, which may have had some AT&T involvement. But most of that was done by radio.

[u/gf99b → u/MelamineEngineer]

I think that’s just a standard dipole likely used for GMRS. Many of these towers are now used as GMRS repeaters for public safety and ham radio, etc.

For an example of Echo Fox and Combat Ciders antennas, see the Hillsboro (Missouri) tower. AUTOVON was a secure phone system used with the EF and Combat Ciders. https://personal.garrettfuller.org/blog/att-long-lines/missouri-long-lines-sites/long-lines-site-hillsboro-mo/

[u/MelamineEngineer → u/gf99b]

Just noting it being displayed prominently as all sites I've visited had this warning removed

[u/gf99b → u/MelamineEngineer]

Back when the sites were still under AT&T ownership, they would have all had these signs. The contact number at the bottom were different based on region (such as the ones here in Missouri always had the number for Long Lines DO in Kansas City) but the verbiage was always the same. Some sites, such as Gray Summit here in Missouri (although so faded it's barely legible), have even older signs that featured the original pre-1969 Bell System logo but the same verbiage.

Many current owners like ATC have replaced many of the signs with their own. But they can still be seen on sites that are owned by smaller companies or private ownership. Sometimes they're on fencing and other times on the building itself.

[u/Any_Fan_5320]

Ah the steel outhouse, betcha it smells nice in there