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From: johncunliffe@astec.com
Subject: Re[2]: My Spread Spectrum Letter to FCC
Date: Tue, 3 Dec 1996 08:27:46 -0800

``______________________________ Reply Separator _________________________________ Subject: Re: My Spread Spectrum Letter to FCC Author: barron@liant.com at internet Date: 12/2/96 2:02 PM

`Bob,


> What bothers me at the moment is that all of the TAPR STA participants
> who have a specific experiment are listed as 900 MHz Frequency Hopping
> with one watt. This is probably inevitable, given just 6 months by the
> STA. My opinion is that there is **SO** much crud on 900 that
> interference tests on that band will be essentially meaningless.

All the more reason for weak signal ops to participate. There can be a meaningful investigation of this if the weak signal use their equipment to test whether SS signals will adversely affect their performance.

As an example. An SS transmitter is turned on and a long sequence sent (or not) every time slice. The choice of transmit or not is random and not known to the WS listener. The WS listener listens to the WS calling freq and attempts to determine when the SS transmitter is actually sending. Will the WS station be able to tell the difference? Maybe. Maybe it all depends on the antenna positioning, power, proximity, etc.

Actually one can do this type of testing without an STA just by using Part 15 devices that are available to everyone. Has anyone else ever tried this?

Come to my house and see what happens when the guy 4 houses down switches on his 900Mhz cordless phone. He bought that because of interference to the old 49 Mhz phone. And yes it is SS. The noise level is pinging my meter with my 60 element looper pointed his direction from 902-910 Mhz ( that is the range I can receive) and so effectively blocking QSO's from east. Turning the antenna shows no spot with noise below S6. When he is done with his calls (this can be hrs at a time he has a 16 Year old :-) )the noisefloor is around an average of S1. Lately there have been popping up some 2-3 more signals from different directions but not as strong. I chose to not use 900Mhz and right now the antennas are down and I will concentrate on other bands. This one was an easy decision for me, after all, even here in Rochester with all the BIG activity on VHF and above the VHF/UHF/SHF bands are empty besides the times just a couple weeks before the contests and during the contests.

John

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