[GreenKeys] (no subject)

[TELEGRAPHER at att.net]

Just because towers face one direction or another doesn't mean the circuits therein go the same direction.  Those towers did not go in a straight line between cities or destination.  If you were to look at a map of the US with the tower placements situated on it, you'd see crooked lines instead f straight lines.  I saw a number someplace but can't remember where or what the value was but i think the towers were 35 degrees or so offset from the enxt one down the line.  Reason.  If they were all in a straight line you could have a situation where propagation could be such that signals from one tower might be heard or seen in one further down the line causing confusion in the system.  Why?  Well at some of those sites, where you see antennas they demodulated the carrier signals off the route and then reroute the various circuits as required by the CLLR or service orders.  Usually when they did that, the reroute or drop and add was at the minimum a group of channels.  Although if needed for additional capacity at one of the offset stations, they might drop an entire supergroup from one direction and route it to a radio channel going off at a tangent from a station.  All the radio sites were regenerative type.  In otherwords, they did not come into one antenna and immediately go out of another antenna.  They came in thru a radio, cross the station to antother radio and back out again.  If there were no circuits or groups, supergroups to be split off in the station, between radios was just a piece of 75 ohm coax that may or maynot make appearances at a jack panel.  Also radio stations were operated either with space or frequency in a hot standby configuration.

Keep this in mind, so 5 groups (12 channels per group)made up a super group(60 channels).  Man it's been awhile so i hope those numbers are right. 10 Super groups made up a Master group.  My only experience with that stuff was the most one of those stations would handle on an antenna was 3 mastergroups.  I think when they went to SSB they might have enhanced that but i'm not sure.  The main radio at the time i was working carrier and microwave radio was the TH-3.  Most of it was 2 watt output stuff.  

Bell system radio at least in Mtn Bell was TL/TM2 which was limited capacity or for small routes.  Anything large capacity went to AT&T for their carrier services.  As an example, Cheyenne radio used TL/TM2 to go west to Rawlins and points west and spurs to the north.  going north to Casper, Billings etc we went SO. to an AT&T site, something Junction where they picked up our trunks and circuits going north, dropping them off as required at stations closest to their destination and putting them back on local Bell system carrier facilities.  going south to Denver everything went to the AT&T site south of us via TH3 radio because of the large numbers of trunks and circuits and then on towards Denver for further breakout and rerouting.  Going to the east we had a GE 4 Gig radio that never had more than maybe 30-40 channels on it which fed two small towns to the east and also tied in "in the air" with Scottsbluff, NE.  that finally went away and as all our small -medium cap stuff did with Collins MDR-6 and 11 digital radio.  

Phoenix has an AT&T building right down town that we sent all the message trunks and other stuff to which was then sent via microwave to ApacheJct.  This was actually a site on the NW side of Apache Jct that sets up in a notch of a hill. I forget where it went from there but it eventually went thru a site up in the beautiful white mountains east of Lakeside/Pinetop.  I think then it went north to a site just SW of Holbrook, AZ.  If you know where to look when coming across I-40, when you get just west of Holbrook look off to the south-southwest and you'll see this lonly outpost from another era.  Another one is on the NE side of Flagstaff again off of I-40.  I'm sure it ties in with the one over at Holbrook although i don't know just where the intermediate tower(s) are.  They are not in a straight line though i now this for certain.

Have fun.

Larry
W0OGH
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