Jeff Liebermann wrote:
On Fri, 18 Sep 2009 10:56:09 -0700, Joerg
wrote:
Does anyone else have such drop-outs in locations with lots of RF
reflectors, and maybe an easy fix/hack?
I don't but two of my customers have the problem. They're located
directly opposite a downtown Santa Cruz CA rooftop loaded with
cellular antennas. When the handsets are anywhere near the window
facing the cell site, they drop out. Range is irrelevent as the base
unit is in the same office as the handset user. I don't recall the
exact models, but one is a 4 phone Panasonic, while the other is a 4
phone Uniden (as probably sold by Costco).
Aha, thanks, now we are getting closer. We have a Panasonic set of
three, from BestBuy but similar to the ones they now sell at Costco. I
can't imagine them not using the same chip set.
It's the comm from handset to base that drops out, base to handset never
drops out. The next cell tower is about a mile away though but we are on
top of a knoll.
The problem is that in the US, the DECT 6.0 phones operate on
1920-1930MHz. PCS cellular base to mobile is next door at
1930-1990Mhz.
http://en.wikipedia.org/wiki/Cellular_frequencies
http://en.wikipedia.org/wiki/Dect
It's the sheer power of the PCS cell site that rips on the DECT 6.0
phones. There's just not enough receiver selectivity and overload
tolerance available in the average DECT 6.0 handset to coexist in such
an RF environment. The receiver either blocks or hears PCS crud, and
it drops out. ...
I would assume the base could also be fooled by a signal from a cell
phone itself if close enough. Why did they screw up the chip sets so
badly? I mean, I can stand right next to a guy with another cell phone
at the airport or even inside the metal fuselage of an airplane (after
landing) and nothing interferes. Did the DECT guys screw it up?
... The best you can do is position yourself away from your
local cell sites or switch to 5.7GHz cordless phones.
5.7GHz doesn't stand a chance in this location. Not enough oomph up there.
--
Regards, Joerg
http://www.analogconsultants.com/
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