Odd coverage map: West of Phoenix

[Gideon H]

I was messing around with T-Mobile's coverage locator and I found a weird mess of coverage west of Phoenix. Its like a big cicle with mixed amounts of coverage in it. Why is it like that? I attached a screen shot.

[Andy]

It might be a boomer on top of a mountain spreading the signal like that?
This looks somewhat similar of my area.

[Gideon H]

Yea you have a couple of them dont ya? But why is the signal restricted to a circle?

[Andy]

I have no idea. The only explanation I can come up with is that the signal is boosted into those directions from a very powerful tower that's high up in altitude.

[BillRadio]

I have no idea. The only explanation I can come up with is that the signal is boosted into those directions from a very powerful tower that's high up in altitude.

The circle may be the extent that the signal is reliable for that site, even if there is sufficient strength beyond. So far, the most impressive I have seen is the huge dark green half-circle radiating from what appears to be Pike's Peak. Enter "Fountain, CO" as your city, and behold. And the signal improves as you travel away from the mountain, typical of a very high site...14,200 feet!

[larry]

That circle of coverage is kind of odd. I noticed some weird things like that on T-Mobile's So. cal maps as well. They have one rural part of Riverside County showing a huge amount of coverage in an unpopulated mountainous area that I know they can't really be covering that well.

[roamer1]

why is the signal restricted to a circle?

The map probably takes into account the 35 km distance limitation of GSM.

-SC

[Gideon H]

The circle may be the extent that the signal is reliable for that site, even if there is sufficient strength beyond. So far, the most impressive I have seen is the huge dark green half-circle radiating from what appears to be Pike's Peak. Enter "Fountain, CO" as your city, and behold. And the signal improves as you travel away from the mountain, typical of a very high site...14,200 feet!

Wow that's interesting. So I guess these are results of towers on top of mountains... I remember seeing them a lot in the distance when I lived in Phoenix so I guess that is why they show-up like that!

[azcellphonejunkie]

The circle may be the extent that the signal is reliable for that site, even if there is sufficient strength beyond. So far, the most impressive I have seen is the huge dark green half-circle radiating from what appears to be Pike's Peak. Enter "Fountain, CO" as your city, and behold. And the signal improves as you travel away from the mountain, typical of a very high site...14,200 feet!

Very cool! I have noticed that on a lot of the coverage map for T-Mobile in the western states. It would figure Bill's answer makes sense...

[Andy]

The circle may be the extent that the signal is reliable for that site, even if there is sufficient strength beyond. So far, the most impressive I have seen is the huge dark green half-circle radiating from what appears to be Pike's Peak. Enter "Fountain, CO" as your city, and behold. And the signal improves as you travel away from the mountain, typical of a very high site...14,200 feet!

Seems like T-Mobile leaves out the west sectors from that specific tower...is that just unpopulated backcountry then?

[BillRadio]

Seems like T-Mobile leaves out the west sectors from that specific tower...is that just unpopulated backcountry then?

If the site is on the top of this mountain, the western half of Colorado Springs would be in the shadow of the mountain and would not be able to see the site. Also, the signal would be directed toward the horizon which means locations a mile below the narrow beam width would not get a usuable signal. So, on the west side of town, normal cell sites fill in.

The areas with no coverage are not populated enough to justify even adding an additional sector. You'll also notice there is no coverage spot for where the actual cell site would be located...it's hard to get there.

I concur with Roamer1 that the edge of these circles are at about the 35 km limit of useful GSM coverage. I was just astounded that the Colorado Springs coverage within this circle is all dark green.

Also, I am guessing that this T-Mobile site is really on top of Cheyenne Mountain which has a slightly better "view" of Colorado Springs. That's where all the TV towers are, and good power, mounting locations and access would be available. Still, a very high site, and yes, that is the mountain under which NORAD headquarters is buried.

[Andy]

Is there a lot of outdoor activities held in the areas where there is no sector pointing to it? If so, then it would make a lot of people happy to have a usable signal in the area, and really wouldn't cost T-Mobile anything to add another sector(...it doesn't really cost a lot other than the equipment, correct?). That's one thing VZW does on some sites in rural areas here. They do add that additional sector to give coverage to places where you usually don't find a lot of people, but if you go out there for outdoor activities, people are happy their phones work.

[BillRadio]

Is there a lot of outdoor activities held in the areas where there is no sector pointing to it?

No, there isn't much there, not even roads. If it is indeed on Cheyenne Mountain, which is just in front of Pike's Peak, the signal would just be directed into solid granite.

That's one thing VZW does on some sites in rural areas here. They do add that additional sector to give coverage to places where you usually don't find a lot of people, but if you go out there for outdoor activities, people are happy their phones work.

Rural Verizon sites, even those built here in the past year, have omni-directional, or only slightly-directional antennas (non-sectorized), so they cover all around the site...something T-Mobile can't do.

[Andy]

...something T-Mobile can't do.

Sorry if this is a dumb question...but why not?

[BillRadio]

Sorry if this is a dumb question...but why not?

The way PCS carriers can radiate a useful signal is to concentrate the signal with a directional antenna. Typically, a PCS transmitter radiates 8, and in some cases 16 watts, whereas a Cellular transmitter can have as much as 500 watts. To make such low PCS power levels work, the antenna must 'focus' the signal in both the horizontal and vertical planes, realizing as much as a 10- to 15-times virtual power 'increase'.

So, a PCS signal can be almost as powerful as a cellular signal, but only in a concentrated spot.

There are omnidirectional PCS antennas. They are used along roads where the only use of the signal is among drivers. Sprint has dozens of them along the roads that cross the Santa Monica Mountains in CA. I can measure the range of each of these antennas at about .7 mile, maximum. That kind of range would not be worth the cost of a full site, but does offer a reasonably-priced alternative in areas where even a directional antenna would not cover a radius beyond a half mile due to line-of-sight limitations on those curvy roads.

[Andy]

Very interesting, Bill. I did not know that. So bottom line is that 800 carriers don't only have better penetration because of the lower frequency, but also because they are able to use more power on their sites, correct?