Topband: FW: The WD8DSB mini-flag antenna (LONG!)

[John Kaufmann]

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 at contesting.com] On Behalf Of Lee STRAHAN
Sent: Thursday, February 25, 2021 4:46 PM
To: topband at 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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