I am sharing your informal spectrum survey with others on the
BOAR-net Google Group
Thank you for doing this professional microwave spectrum survey in
the Washington, DC area. It shows that the spectrum at 3.4 GHz is
much cleaner than at 5.8 GHz. For your convenience, I've attached
plots in the ham bands at 2.4 GHz, 3.4 GHz and at 5.8 GHz -- see
attached.
-------- Forwarded Message --------
Subject:
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Informal spectrum survey |
Date: |
Thu, 18 Sep 2014 23:35:47 -0400 |
From: |
Mark Braunstein WA4KFZ <wa4...@cox.net> |
To: |
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CC: |
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Earlier this week, I borrowed a spectrum analzyer and wideband
discone antenna (1-6GHz) from work and drove to three locations in
order to get a sense of what the interference environment looks
like. The measurements were made in the 2.4GHz, 3.4GHz and 5.8GHz
bands. The sweeps extended 100 MHz below, and 100MHz above, the
amateur allocations for each band. The allocations pertain to all
three ITU regions. The spectrum analyzer was set to "max hold" and
I recorded at least 3 minutes of environmental activity. The
analyzer's displayed average noise level was around -90dBm, which
encompasses the minimum levels that BBHN equipment typically see.
The Home measurements were conducted on my deck. The Work and
Walmart measurements were conducted with the analyzer on the trunk
of my car.
Needless to say, the 2.4GHz spectrum is heavily occupied!On top of
that, Cox Communications has setup a high-power WiFi distribution
system nearby, further contaminating the environment. The signals
at 2.4GHz were so strong that, in actuality, they extended past
the reference level of the spectrum analyzer (i.e., at least
40-50dB above the displayed noise level).
The Excel spreadsheets contain 550 measurement points, so each
measurement is just over 1 MHz apart. You can re-plot the data to
see how things look inside any particular portion of the spectrum.
We definitely need to get out of the conventional 2.4GHz
allocations!
--
73,
Mark D. Braunstein WA4KFZ
Ole Virginia Hams