At the FBCC we found an abandoned tower about 800 feet due north of the building. This tower is co-located with the town's water towers on a 50' hill. The tower height is estimated at 60'. It is currently a self supporting triangular tower with 3' faces. Although there are signs that there was power at the tower, currently it is not plumbed in. There is a small box next to the tower were the power once ran into. The box is not a rack nor big enough to contain our gear.

The reservation has one Tribal owned FM broadcast station (KMHA) with a tower ([Image1] [Image2]) located next to Mandaree. The studios are located next to the tribal offices about 4.7 miles due west. Their studios pass programming to the transmitter site with a 950MHz studio to transmitter link (STL). The overall height of the tower is 377' with the top portion supporting a 12 bay antenna for the FM transmitter. This takes about 164'. There is some room just below this array at about the 200' level. The KMHA STL antenna is about mid point up the tower.

With the assumption of the AGL for the antennas and ASL of these towers we have some intrusion in the path about 5.6 miles out from the FBCC tower. With the earth bulge calculated in it blocks the center of radiation. Raising the antenna to 170' AGL at the FBCC tower would clear it.

**NOTE:** One
change in this calculation over the others is using 5/8" transmission
line (LMR-900) for the KMHA site as we need at least 200' for this
location.

Assuming we have a clear shot with the AGL needed on both ends, with 8' dishes we would have a fade margin of 16.3 dB and an uptime of 99.925831% or outages totaling 389.83 minutes a year as there is a some distance on this link.

As Twin Buttes is 27 miles south east of Mandaree. The path must go over the Missouri River and some hills or buttes just south of the river before Twin Buttes such as "Old Man Dancing Butte at 2242'. Unfortunately these hills are higher than the ASL of the tower and cut into the path. There are two ways to approach this. Either build another tower on one of the buttes or raise the BIA tower another 100' to get an AGL of 170'. For this section we are just going to look at the path calculations for the current BIA tower location.

Assuming we have a clear shot with the AGL needed on both ends, with 8' dishes we would have a fade margin of 16.3 dB and an uptime of 99.669931% or outages totaling 1,734.84 minutes a year as there is a some distance on this link. This is not the four "9s" or three "9s" that was asked for by the FBCC staff.

First Hop

Second Hop

There is a downside as there is an additional link for this path. Maintenance costs go up as well as the initial equipment and installation costs.

Again, assuming we have a clear shot with the AGL needed on both ends, with 8' dishes we would have a fade margin of 18.7db with an uptime of 99.984413% or outage of 81.92 minutes per year. If we reduced this to 6' dishes the fade margin would be 13.7dB with an uptime of 99.950711% or outage of 259.06 minutes per year.

Looking at the path from Twin Buttes to this tower in White Sheild we see the same issue where a butte about 2 miles from Twin Butte is blocking the path. An AGL of 170' on the Twin Buttes' tower would be needed to clear this path. If we could clear the butte, this path will work. This revisits the issues with the Twin Buttes tower as outlined above.

Assuming we have a clear shot with the AGL needed on both ends, with 6' dishes we would have a fade margin of 17.2 dB and an uptime of 99.984422% or outages totaling 81.88 minutes a year. 4' dishes would get us 10.4 dB of fade margin with a 99.925437% uptime or 391.90 minutes per year of outages.

If it could ever get this path to work, with 8' dishes at 450' AGL and switching to Andrew EW-52 (6GHz Waveguide) we would have only 15.2 dB of fade margin. With this distance we would have 99.456245% uptime or 2,857.98 minutes per year of outages.

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