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From: hbrown@voicenet.com
Subject: Re: REALITY CHECK! (Received DSSS Signal levels)
Date: Sat, 7 Dec 1996 15:05:35 -0500 (EST)
Phil,

A number of points:

SS does not use a different set of Maxwell's equations so the factor of 4 is just a fudge factor to get the "signal levels" that you find in practice. I can see that it is difficult to model multipath in a city so you guys are practicle and fudge with the signal path equations (the old radar types must cringe at this).

This does not mean that this model that is used for cell phones is in any way correct for ham use. It certainly is not valid for weak signal use or you would not easily explain EME work. Even if it is valid for ham SS to ham SS communications, the interferance products will obey regular maxwells equations which if my 40 year old memory from E&M field theory class is correct, results in the high noise levels that calculatedand were part of some responses to the ARRL request for rule changes. Tell me again why SS interferance levels to CW or SSB signals obey a distance to the 4th power where signals between CW/SSB signals are to the 2nd power. I guess I am being dense.

As for the antiquated non-reuse of frequencies story goes, it sounds like cell phones to me. The size of 2M FM repeater cells is usually around 50 or so miles in radius -likely more, I'm no more of an expert on repeaters than I am on SS. 800 MHz cell phones don't seem to be more than 5 or 6 miles in radius based on the large number of cell sites I see around here. A weak signal guy on CW or SSB can have a cell of at least 200 or 300 miles in radius. We're not talking the same language as to frequency reuse. The ham bands especially the VHF bands have plenty of bandwidth to support all of the FM cells, casual SSB cells and weak signal cells. We reuse the cells like everyone else, the cells are only larger. If the calculated noise levels from SS are real then only equipment that is insensitive to these noise levels seem to have a chance of being usable.

Ham vs commercial signal quality. Except for repeaters, ham signal quality is nowhere close to commercial signal quality. It was never meant to be and won't ever be. There's no reason for it to be. I think that if there was no challenge to communicating ham to ham, either over long distances where propagation is a challenge or with minimum power to get basic communication across ala QRP, or with the challenge of making contacts under difficult conditions such as in contests, ham radio would not exist. If all we wanted to do is talk to each other, we would call each other on the phone.

Just my thoughts. I still have not heard that SS is compatible with weak signal modes (and I would really like for it to be so I could play with it). Sounds like it cell phones on the ham bands which is not my idea of what ham radio is about. Hope again that I am wrong.

73, Harry, W3IIT

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