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Re: [TowerTalk] Measuring Coax Loss

To: "Tower and HF antenna construction topics." <>
Subject: Re: [TowerTalk] Measuring Coax Loss
From: jimlux <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Thu, 11 Feb 2010 21:43:04 -0800
List-post: <">>
Mike Besemer (WM4B) wrote:
> How, it the real world of ham radio, do you experience hearing the
> difference of 3dB daily?
> I'm not talking about a lab.
3dB is the difference between unreadable and barely readable against the 
noise floor.  The difference between the 3kHz and 2.4kHz IF filter on 
SSB is a lot less than 3dB and readily audible on a weak signal (on HF).

   It's probably the difference between somewhat noisy and full quieting 
on a FM rig.

At threshold, 3dB is important.

At S9 or 60 over, 3dB is irrelevant.

Now, if you start talking 1dB... 1dB is very close to a "just noticeable 
difference" in audio levels.. that is, if you have two tones that are 
0.5dB apart in level, you'll have a hard time telling the difference 
between them.  (see, e.g. Weber-Fechner law, etc.)

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