Archived from groups: alt.cellular.verizon (
More info?)
Bruce Crawford wrote:
> On 13 Jul 2005 18:11:55 -0700, vxg49@yahoo.com wrote:
>
>
>>The other day I was atop Mt. Equinox, a 3840-foot peak in southwestern
>>VT, nominally part of Verizon's extended digital coverage (provided by
>>a roaming agreement with U.S. Cellular, I assume). Left to its own
>>devices, the phone would find a Verizon home network (perhaps in NY
>>state, or in central VT), connect to it for about 5 seconds with 2 or 3
>>bars (i.e., pretty strong signal), then disconnect for roughly 10
>>seconds. It kept doing this over and over. By forcing my phone to
>>analog mode (a Samsung A650), I was able to maintain a stable
>>connection.
>>
>>One theory to explain this odd behavior is that the phone could see so
>>many towers from the mountaintop that signals were interfering with one
>>another. Another theory is that there was some source of periodic
>>interference at the mountaintop (which has a lot of broadcasting
>>equipment). Anyone have any other ideas?
>>
>>Thanks.
>
>
> I had problems one week ago in Northern Vermont, in native VZW
> territory (SID 300). I was hiking the Long Trail at elevations in the
> vicinity of 3500 feet, and kept getting "Call Failed" on my Nokia
> 3589i, after two quick drops. Back at lower elevations in the car, I
> could get a call through. Didn't think of trying to force analog.
>
> Bruce
This could also be a result of how CDMA works. The bars indicate the
received signal strength of the base station's pilot channel. Since you
have line of sight to towers many miles away, you may be getting very
good signal strength from the tower, so you get several bars. Then your
phone transmits a "handshake" signal that gets received, but very
weakly. The CDMA protocol then calls for the base station to instruct
all units to adjust their power so that they are received at the base
station at the same strength. Yours is coming in weak but clear, and
it's instructed to increase X dB while others in the more immediate area
are instructed to decrease. Your signal can't be increased enough to be
in balance with the others, so the call is dropped.
With analog, each phone is on its own channel; your phone, being
distant, is powered up to the max, and if that produces a good enough
signal it holds the channel; otherwise the network looks to see if you
can be handed off to another cell that can receive you better. Because
there's no need to balance your power with the others, an analog call
can be maintained under circumstances where a CDMA call would be dropped.
On the other hand, the analog call at maximum power will drain your
handset's battery very quickly.
--
Michael D. Sullivan
Bethesda, MD (USA)
(Replace "example.invalid" with "com" in my address.)