The P3 noise measurement bandwidth was about 100 Hz in my measurements.
Quoting from the P3 user's manual, "the effective bandwidth of the P3 is
generally one display pixel, which is approximately span / 450. I used a span
of 50 kHz, so it comes out to 111 Hz. Because the relationship is only
approximate, I round it to 100 Hz in my calculations, which is good enough for
my purposes. To obtain the noise density in a 1 Hz bandwidth, you just
subtract 20 dB (a factor of 100 for the difference in bandwidth) from the
measured noise level in the P3.
73, John W1FV
-----Original Message-----
From: Topband [mailto:topband-bounces+john.kaufmann=verizon.net@contesting.com]
On Behalf Of Lee STRAHAN
Sent: Thursday, February 25, 2021 4:46 PM
To: topband@contesting.com
Subject: Topband: FW: The WD8DSB mini-flag antenna (LONG!)
Hi John,
What did you use as the P3 bandwidth for your noise measurement? And
conversion to 1Hz equivalent.
The P3 has its own bandwidth and is not affected by setting the receiver
bandwidth.
Lee K7TJR OR
(Note: what follows is a long, technical discussion about noise and “small”
antennas. I invoke some math and physics here, so if you are not comfortable
with it, feel free to disregard or delete this e-mail. I went through this
exercise to help teach myself the limits here and maybe others might find it
helpful or educational as well.)
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