Barely a Sprint signal on Kennesaw Mountain

[TKR]

This is a technical question of sorts.

In Marietta, Georgia, if you go up to the top of Kennesaw Mountain, which is big hill that stand alone about 700 feet or so above local terrain, you barely pick up a sprint signal at the top. You begin to lose signal about half way up. This is despite the fact that there are plenty of towers in all directions of the mountiain, from 1-3 miles away.

Why is it that it is hard for the phone to hold a signal?

Is it that the antenna panels are not aimed up to pick up the slight angle of the elevation? They are not THAT directionally sensitive are they?

Or is it that the phone begins to pick up too many PN offsets and can't handle it all? If so, is this a unique CDMA weakness (too many towers in range)?

We found a Cingular phone a couple of years ago at the top (probably TDMA), and it had a booming signal, so we were easily able to notify the owner using their own phone.

[Andy]

It might be that the towers are not aimed right for you to pick up a signal there, but usually 700 feet don't matter.
I guess it's pilot pollution then. I've been on top of a lot of mountains with my CDMA phone(Verizon) and never experienced pilot pollution problems, even though my phone was able to 'see' tons of towers.

[chris4434]

I have noticed the same problem. It seems like the signal is very poor at the parking lot on the top of the mountain, but once you walk to the actual top the signal becomes strong again. When I was hiking on it my phone kept going from sprint to digital roam to analog roam to no signal.

[Andy]

Any pictures of the mountain/area?

[roamer1]

Originally Posted by TKR This is a technical question of sorts. In Marietta, Georgia, if you go up to the top of Kennesaw Mountain, which is big hill that stand alone about 700 feet or so above local terrain, you barely pick up a sprint signal at the top. You begin to lose signal about half way up. This is despite the fact that there are plenty of towers in all directions of the mountiain, from 1-3 miles away. Why is it that it is hard for the phone to hold a signal?

a) the panels on the nearby sites are tilted downward
b) as SPCS is CDMA, you're probably have issues with pilot pollution -- basically, being able to see too many sites from the top of the mountain.

These sort of issues also exist on the tops of other mountains around Atlanta and north GA, including Stone Mountain (where even VZW CDMA "poops out" and drops to AMPS at the top while non-CDMA carriers generally work fine), Fort Mountain between Chatsworth and Ellijay, etc.

In Chattanooga, which is basically surrounded by mountains, carriers generally avoid the problem by having sites atop Lookout, Signal, White Oak, etc. mountains -- something that's impossible to do in state or national parks or forests, hence the issues at Kennesaw Mountain, Stone Mountain, etc.

-SC

[TKR]

Originally Posted by roamer1 a) the panels on the nearby sites are tilted downward b) as SPCS is CDMA, you're probably have issues with pilot pollution -- basically, being able to see too many sites from the top of the mountain. -SC

I don't pretend to understand how CDMA communication strings actually work with PN offsets, etc. But this type of situation can't be that uncommon a problem. I wonder shouldn't it be possible to deploy a prioritization algorithem in CDMA for this type of situation so that the phone basically tells the network it is getting too much noise and it need to "pick" a tower? Is anything like that possible?

[larry]

Originally Posted by TKR I don't pretend to understand how CDMA communication strings actually work with PN offsets, etc. But this type of situation can't be that uncommon a problem. I wonder shouldn't it be possible to deploy a prioritization algorithem in CDMA for this type of situation so that the phone basically tells the network it is getting too much noise and it need to "pick" a tower? Is anything like that possible?

TKR,

I couldn't agree with you more. And you're right it is a very common problem. You would think by now the CDMA technology would have evolved to help reduce or eliminate the PN offsets that are weak or unusuable but it hasn't. Like roamer1 said it's definetly the old pilot pollution thing when your phone sees too many stray signals at the same time and doesn't know which one to pick. Even though the panels are typically tilted downward a tiny amount of signal will propogate upward. Very seldom are panels aimed upward towards hills but I have seen it.

[Andy]

I've seen panels tilted upward, and there was no mountain or tall building to cover.

[TKR]

Originally Posted by larry TKR, I couldn't agree with you more. And you're right it is a very common problem. You would think by now the CDMA technology would have evolved to help reduce or eliminate the PN offsets that are weak or unusuable but it hasn't. Like roamer1 said it's definetly the old pilot pollution thing when your phone sees too many stray signals at the same time and doesn't know which one to pick. Even though the panels are typically tilted downward a tiny amount of signal will propogate upward. Very seldom are panels aimed upward towards hills but I have seen it.

This particular setting does not present THAT much of an up angle, anway.

[Andy]

So I guess the thing to do *if*Sprint wanted to provide reliable service up there would be to add something like a microcell or very weak cellsite that doesn't cover much surroundings(and spill down,creating problems off the mountain). Just for arguments sake.
Now, a GSM carrier wouldn't have to do this, correct, since a GSM phone can still 'see' through all those offsets and lock onto one single offset, correct?

[larry]

Originally Posted by Andy84094 I've seen panels tilted upward, and there was no mountain or tall building to cover.

I have as well. *shrug*

[larry]

Originally Posted by Andy84094 So I guess the thing to do *if*Sprint wanted to provide reliable service up there would be to add something like a microcell or very weak cellsite that doesn't cover much surroundings(and spill down,creating problems off the mountain). Just for arguments sake. Now, a GSM carrier wouldn't have to do this, correct, since a GSM phone can still 'see' through all those offsets and lock onto one single offset, correct?

I believe that GSM has similar problems in situations like this that's caused by a different issue. Maybe someone else can explain it better.

[Andy]

Originally Posted by larry I believe that GSM has similar problems in situations like this that's caused by a different issue. Maybe someone else can explain it better.

I didn't know that was the case. I will do some resarch and post it here if I find anything.

[TKR]

Well, I went up to the summit yesterday with my new 2300 (which can digitally roam and also has a better service screen than my old 4900).

I put the phone in both Sprint and Verizon roaming modes. Both providers suffered from very weak signal bars. However, VZW was getting about -75dB and Sprint about -85 dB, so there was no lack of overall signal. However, the Ec/Io reading for both were typically between -15 and -25 dB, or worse. That means a lot of noise, so the issue would seem to be pilot pollution.

It would be nice if they could come up with a CDMA filtering/proccessing algorithem to allow better functionality in such "noisy" signal environments.