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TCP-group 1991

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SS and AR

     Below is an excerpt of a posting I made to the group yesterday:

>>It's hard to explain the last years of tinkering and thinking, but some of
>>the things worth noting include:
>>1)  Radio receivers intended to work in LAN environment ( 50-200 ft)
>>    don't have to be as sensitive as receivers for MANs or even WANS.
>>    Those PROXIMs work to about -40dBm.  The units Glenn put together
>>    so far work down to about -75dBm.  That HT on your belt goes down
>>    to -110 dBm ( ignoring or lumping a few Ktb's in).
>     Thanks for pointing this out.  You are correct that the Proxim units were
>designed for the LAN environment.  The units which I am now playing with work
>at -90 dBm.

Upon reviewing this posting, Mike Chepponis K3MC, who is a part of this effort,
made the following comments to me which I thought were important to post:

Only _minor, minor_ thing is -90dBm figure; basically that is the value that
the detector begins to work (I believe).  I would think that this figures are
comparing apples & oranges.  In particular, if Glenn's radios do -75 dBm, then
the Proxim radios *certainly* do no better than -60 dBm or so (***if that***).
This is because I have a diagram of Glenn's radio, and it is a very carefully
engineered radio & front end, etc.  That is, -75 dBm is damn near state-of-the
art for a 250 kbit/sec data rate.  So the problem with Proxim's numbers vs
Glenn's numbers is that they must be comparing different things; they way the
numbers are now suggest that Glenn's radios are deaf, when, in fact, we know
that the Proxim boxes could use a system noise figure reduction.

     I hope that clarifies the earlier posting a bit for those who are

-- Dewayne WA8DZP
Internet: 75210.10@@compuserve.com

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