Hi Jim,
Yes, your numbers are correct - here are the formulae:
k = 1.38 x 10^-23 Joules/(deg K)
T = 290 K
B = 10^6 Hz
Pdbm = 10 * log (kTB) + 30 = -113.9 dBm
73 de Mike, W4EF.......................................
----- Original Message -----
From: "Jim Reid" <jimr.reid@verizon.net>
To: <towertalk@contesting.com>
Sent: Sunday, December 30, 2001 10:28 AM
Subject: [TowerTalk] Thermal Noise Levels
>
> Hi,
>
> Need my memory jogged! I believe I recall that
> the kTB value, at near room temperature, and
> in a 1 mHz bandwidth, the formula will calculate to be
> -114 dBm of noise power -- is this correct? Or
> close. If so, and the bw were narrowed to 1 kHz,
> a 30 dB shrinkage, the noise power would then
> be -144 dBm. These numbers seem about correct.
> Appreciate a correction if I am not doing this right, hi.
> Yes, the correct units must be used, degrees K, but
> I have no reference out here to the value of Boltzman's
> constant, B.
>
> 73, Jim KH7M
>
>
>
> AN Wireless Self Supporting Towers are now available! Windloading tables,
> foundation diagrams and charts, along with full details are now at the
> AN Wireless Web site: http://www.ANWireless.com
>
> -----
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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>
>
AN Wireless Self Supporting Towers are now available! Windloading tables,
foundation diagrams and charts, along with full details are now at the
AN Wireless Web site: http://www.ANWireless.com
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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