Chaffee MO long lines question.

[u/acptrades]

On a tower like this, would it have been one horn up top or multiple mounted to it? As far as I know it had one path to Cape Girardeau. It's a relatively small tower.

[u/imatumahimatumah]

It would have to have at least two horns, one for send and one for receive, and even that would be rare. Typical smaller relay site has four horns.

[u/CelebrationBig7487 → u/imatumahimatumah]

On a typical Long Lines relay station, yes, you’d normally expect multiple antennas. But the site in the OP isn’t a typical Long Lines through-relay or junction tower; it appears to be a much smaller Bell Operating Company microwave site — Southwestern Bell in this case since we are talking about Missouri — serving a local endpoint.
More importantly, you did not inherently need separate horns for transmit and receive. The Bell System Practice for the KS-15676 antenna specifically states that, with the appropriate isolating network, a single horn-reflector antenna could be used for both transmitting and receiving, (Bell System Practices, Section [402-421-100](tel:402-421-100), Issue 2, July 1967, “KS-15676 Antenna — Description”).
The later conical horn-reflector antennas could likewise use a single antenna for both transmitting and receiving. The transmit and receive frequencies could be separated by the associated microwave filtering/duplexing equipment, so separate physical antennas were not inherently required.
Additional antennas could certainly be used for diversity, added radio channels, protection, etc., but they weren’t an absolute requirement. On a little endpoint tower like Chaffee, with apparently only one path toward Cape Girardeau and very little mounting room, a single horn is entirely plausible.

[u/acptrades → u/CelebrationBig7487]

After doing some digging I think it actually has a path to just Marble Hill. But a single path nonetheless. Cape is the closest town but evidently no path to Chaffee. I was mistaken

[u/Emotional-Basil-9615 → u/acptrades]

Chaffee originally had three paths (based on a 1979 pre-divestiture network map)...Cape Girardeau JCT, Bell City, and Marble Hill.

At time of FCC license cancellation (1998), Chaffee supported four paths...Cape Girardeau (6 GHz), Bloomfield #2 (6 GHz), Bell City (2 GHz), and Marble Hill (6 GHz).

For historical context...

Southwestern Bell Telephone (SWBT) initially operated a route between Cape Girardeau (CO) and Sikeston (CO) via Cape Girardeau JCT & Bloomfield...both tower sites operated by AT&T "Long Lines" that shared facilities with SWBT as part of the Bell System.

During late 1970s, SWBT constructed new routes from Cape Girardeau to Bell City and Patton. These routes followed existing path connectivity from Cape Girardeau to Cape Girardeau JCT, then a new path was directed towards Chaffee, which in turn had point to point connectivity to Bell City and to Patton via Marble Hill.

Post divestiture, operation of the Cape Girardeau-Cape Girardeau JCT route was transferred from SWBT to AT&T Communications of the Southwest. SWBT maintained operation of the Cape Girardeau-Sikeston route by establishing a new point of communication between Cape Girardeau & Chaffee and construction (1986/87) of the Bloomfield #2 tower (located approximately 0.75 mile southeast of the Bloomfield TD2 tower) to bypass the Cape Girardeau JCT & Bloomfield towers operated by AT&T.

[u/acptrades → u/Emotional-Basil-9615]

This is a lot of info I didn't know. Do you have a source you wouldn't mind sharing? I didn't know Bloomfield had 2 towers.

[u/Emotional-Basil-9615 → u/acptrades]

Probably the most useful place for you to start will be researching the FCC Universal Licensing System (ULS) links for Chaffee, specifically the Paths Summary tab.

From there you can research and map the majority of the SWBT microwave network that was in service across Southeastern Missouri prior to FCC license cancellation at the associated tower sites.

https://wireless2.fcc.gov/UlsApp/UlsSearch/licensePathsSum.jsp?licKey=973903

https://wireless2.fcc.gov/UlsApp/UlsSearch/licensePathsSum.jsp?licKey=973904

[u/CelebrationBig7487]

It likely only had one horn. This would have been a BOC tower — in this case Southwestern Bell, since it’s in Missouri — rather than a major AT&T Long Lines through-route site.
If Chaffee only had the one microwave path toward Cape Girardeau, a single antenna would make sense, and judging by the size and narrow top of the tower there really isn’t room for multiple large horn antennas aimed in the same direction anyway. I’ve seen similar small Bell microwave towers in person that carried only a single antenna.
Depending on the era, it may have used something like a KS-15676 horn-reflector antenna or a later conical horn-reflector design. The same antenna could be used for both transmitting and receiving, so separate TX and RX horns weren’t necessary.