[By Subject] [By Date] [By Sender [By Thread]
Previous In Time

Next in Time

From: karn@qualcomm.com
Subject: Re: W3OTC's quote from the W3IWI/KA9Q EME paper
Date: Tue, 3 Dec 1996 14:52:16 -0800 (PST)
By the way, just to show you this spread spectrum stuff isn't all theory, I am typing this message from my laptop while sitting indoors at the local food court near work.

I am logged into my office workstation over a Qualcomm CDMA (spread spectrum -- 1.25 MHz bandwidth) cell phone operating in the 1.9 GHz PCS band. The phone is plugged into the serial port on my laptop, and it's carrying TCP/IP/PPP packets from the Linux operating system on my laptop to the company Internet and thence to the outside world.

The cell site is perhaps a mile or two away on a 2-story building, and the phone is just resting on the top of my bag in a horizontal position. The path is not especially strong; I see only one bar on the signal strength meter. Yet thanks to the strong coding and inherent multipath resistance of spread spectrum, the TCP packet loss rate is nil -- even character-at-a-time typing works just fine.

Phil

------ Submissions: vhf@w6yx.stanford.edu Subscription/removal requests: vhf-request@w6yx.stanford.edu Human list administrator: vhf-approval@w6yx.stanford.edu