The sites owned by Mac Pass
Radio, LLC were all constructed by American Telephone and Telegraph Company.
In Montana there is basically an East-West
path and a North-South path. Many
of the sites shown were shared with Mountain Bell or were outright owned
by the local Bell Company, Mountain Bell later known as US West and even
later Qwest. Many of the facilities were leased to US West for the last
several years of their ownership with AT&T only acting as landlord with
no equipment of their own remaining in the buildings. The primary AT&T
facilities pretty much followed the Interstates from Mullan to Miles City
and from Dillon to Cut Bank. Based on research and on blueprints found in
the sites, some information can be determined about the sites we own. First,
it appears that our sites on the East-West path, Lookout Pass (Mullan),
Gold Creek, MacDonald Pass (Helena Jct), and Toston were constructed in
the late 1950s, while our North South path sites, North Hill (Lake Helena),
Boulder Hill (Wickes), and Badger Pass (Bannack) were constructed in the
Interestingly, the east-west
sites were not constructed as "sturdy" as the north-south sites.
These east-west sites were constructed primarily of Cinder Block with supporting
solid concrete beams running from the floors up to and across the ceilings
and back down the opposite wall. These beams are about 18 inch thick. The
roofs and floors are solid concrete. These sites were all built under AT&T
nuclear hardening specs, but were at a lesser survivability, around 2psi.
The sites associated with the north-south path are all the highly nuclear
hardened sites with blueprints showing a design capable of withstanding
a 50psi load on the buildings and are constructed of all concrete, with
the walls being 12 inch thick poured mil-spec concrete. In about 1986, AT&T
decided that the insulating value of solid concrete walls and roofs was
not adequate, and all of our sites had an outer layer of 4 inch styrofoam
covered with stucco added to the walls. The roofs were also insulated and
steel covering placed over them. The towers are all constructed in the same
design, with only the height and number of platforms being custom to the
individual sites. The tower height and actual site location themselves are
interesting. In several cases, the sites are located at the less than optimal
location of a hill, with the tower height making the difference in the line
of site path. As individuals who are primarily interested in two-way radio
coverage, we had to scratch our heads on a couple of the sites. Toston and
Gold Creek are prime examples. AT&T had the "power" to locate
their sites anywhere, yet at Gold Creek and Toston, rather than locate them
a half mile away at a location on top of a hill, they chose a lower altitude
site. It was determined that the reason for this was to eliminate the possibility
of terrestrial interference from other microwave users as much as possible,
shielding their receive KS-15676 cornucopia horns from as much "air"
as possible, leaving just the slightest margin of "line of site"
between their own sites. Remembering the state of the art in the late 50s
both in antenna design and tube type receiver performance, this was probably
a very smart move. Typically AT&T sites are not great two-way sites
as they were designed simply to pass a Microwave signal from point A to
point B, and VHF/UHF signal coverage was not even considered in their placement.
Fortunately, being mountainous Montana, most of the sites we own are at
higher elevations overlooking large areas of towns, roads, and highways.
MacDonald Pass is a particularly rare AT&T site in that it provides
tremendous two-way and paging coverage, however even it needed help. The
North Hills site (Lake Helena) was built solely to get the path from MacDonald
Pass (Helena Junction) around a small mountain called Mount Helena to the
East Helena site. This site was blocked from line of site from MacDonald
Pass, as was the Mountain Bell office in downtown Helena, so ATT sent the
signal "out of it's way" to the Lake Helena site and then back
to East Helena, which then sent a signal to downtown Helena.
All of the sites have the same
type Microwave Antennas on the towers, model KS-15676 L9's and L14's operating at 4, 6, and 11Ghz with approximately
40 to 45 db gain. These were constructed by Goodyear Aircraft in Akron,
Ohio and Rohr Corporation of Chula Vista, California for Western Electric.
All of the horns that we have looked at have the original labels and serial
number plates on them. As should be expected, our east-west sites have the
L9 versions while the north-south sites have the hardened L14 antennas,
matching the building construction. Although we plan to remove most of these antennas to make room for two-way
antennas, there are one or two that will be left where they are for the
visual and historical value. The antennas weigh approximately 1800 pounds
each, constructed primarily of aluminum. Feeding these antennas are many
feet of rectangular and circular copper waveguide. This waveguide was "dehydrated"
by dehydrators that kept a constant flow of air inside the hollow sections
of the rectangular shaped waveguide. This prevented condensation from forming
inside the waveguide that would be very bad for the unrestricted flow of
the microwaves to and from the antennas. Several of our sites still have
the dehydrators in the buildings. We are not sure who the manufacturer is/was
for the towers themselves, but whoever they are, they should be proud! All
of the towers are still in excellent condition, the galvanizing having done
its job for several decades. The black ink used to identify each tower piece,
a sort of "A goes to B, connects to C" assembly instruction, is
still on the pieces, and look as if they were written on these pieces last
year. Montana sees a widely varying weather year. The towers have seen decades
of 80+MPH winds, temperatures from -45 to over 100 degrees, and icing conditions
that would crush your average Rohn 25. The only signs of rust are from attachments
to the tower, not the tower or platforms themselves. And bolts, nuts, and
lock washers. There has to be several thousand of each, and no sign of any
being missing or having come loose. Again, the towers were designed for
a single purpose, and will take some creative mounting ideas for some two-way
antennas, but fortunately, most of our sites were "retrofitted"
at some time for the addition of round style microwave dishes for 12Ghz.
These retrofits consisted of large 4 to 6 inch pipes mounted below the platforms
at each corner. AT&T seemingly removed these antennas at most of the
sites prior to abandoning the facility. Some of our renters have found these
to be ideal points for their microwave antenna placement.
Electrical power to these sites
is also creative. In Montana we have found a mix of either 208VAC three-phase
power, to simple 240VAC single-phase. All of the sites had or have demand
style meters that register peak current draw into the buildings. We have
had to replace some of these with typical 200 amp service entrances at the
request of the power company. Most of the sites were set up with 800 amp
service, and peak demands of over 10KW was not uncommon. Between the large
ventilation systems and heating blowers, along with some sites having "Electrostatic"
anti-dust systems, large peak demands were possible. Each of our sites had
General Motors/Detroit Diesel generators in a separate room within the building.
All of these generators were diesel powered and were either 30 or 45 kilowatt
output. These generators were designed with auto-start systems and after
the generators had warmed up, automatic transfer switches switched building
power to the generator. As AT&T operated the microwave equipment from
battery, there was a certain amount of backup power that allowed for short
power outages to be handled without the need for the generator. The generators
in our buildings all have less than 2000 hours of run time, and much of
that was from scheduled exercise runs, so they were not heavily used, a
testament to the power company (highly unlikely), or more likely, an ample
amount of spare battery current in those large battery banks. Speaking of
diesel, diesel was the reason there is an LLC at the end of our company
name. LLC for those who may not know, means Limited Liability Company. The
single major liability with these facilities are the fact that almost all
of them has or had underground diesel storage tanks associated not only
with the generators, but also diesel heating furnaces. These were large
tanks, MacDonald Pass having had two 3000 gallon tanks. Underground fuel
tanks are a real hot button with State and Federal EPA types these days,
and can cost millions in clean-up issues, and hence the LLC. As we discovered
after buying MacDonald Pass, a company in Montana named Dick Anderson Construction
was contracted by AT&T in 1994 to remove, clean up, test, and dispose
of these tanks. They backfilled the holes, tamped them down, regraded, and
then put new gravel over the areas. After talking to their people, and having
later found the actual contracts and blueprints, they did this cleanup at
all Montana AT&T sites, and fortunately, all of our sites have been
confirmed to be diesel free. A warning to others, this IS NOT THE CASE US
WIDE!!! It is interesting that AT&T elected to spend such a large amount
of dollars, at least in Montana, when by 1994 these sites were all but done.
An additional indication of AT&Ts hazardous material concerns are found
in a couple of the site's floors. Asbestos floor tiles that were used in
two of the facilities were actualy removed to eliminate asbestos issues,
again though, not everywhere.
One last bit of AT&T history
with one of our sites. The MacDonald Pass site had, and still has the antennas
to prove it, the Echo-Fox communications system. This was the air to ground
telephone system used by the White House Communications Agency for communications
with the Military Airlift Command's VIP transport squadron's aircraft, the
most visible of these aircraft being Air Force One. This system consisted
of a full duplex UHF (415 Mhz) radio system that was hard wired directly
to the White House's "Crown" and later "Signal" switchboard.
This system consisted of a single UHF Omni directional fiberglass antenna
connected to the air to ground full duplex transceiver and two small UHF
ground plain antennas connected to a complex system used to remotely test
the operational readiness of the equipment. The Mac Pass Echo-Fox system will be modified in the spring of 2003,
however, we are planning on using the mount and the 7/8s heliax that once
fed the vertical antenna with presidential calls. We plan on installing
a very similar antenna at the same place for our amateur repeater, utilizing
the 20 year old heliax to our repeater transmitter. Visually, with our new
antenna, the echo-fox structure will appear to be the original. The heliax
looks like new and hopefully will still be electrically sound.
This is currently all we know
about our sites history with AT&T. If anyone knows something more, please
feel free to e-mail us and we will add the information here.