Return to KLUBNL.PL main page

[Top] [All Lists]

Re: LF: CW 477.7 kHz

To: [email protected]
Subject: Re: LF: CW 477.7 kHz
From: Andy Talbot <[email protected]>
Date: Sat, 23 Sep 2017 12:12:06 +0100
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=bmxiEjlFHbpmcVkj5tOO8GKiR0W3CBvubIOPp/JkjKE=; b=koXX/G6pAJu59RE413PfoeUjrC7uag0o0qm3bA0erIrK2ewoPq3PfT6yE1i7T0mH1B axLSmvbhFZIuiJNqJHP3f4b1WiQ5om5QonXV+d4R3izycSHnPHSpIaQhMbkZ4RwVXQWP awo8vX3OtvYdWvDvVj8OGB9fgDMbz0c4HjgdE7hExVFm+w/DuGAnyRBaGcYBbrWzLL7A NoR49goY0wSLBuO6YS2+vdIualOi4f37tTDSIGl5Kn3R1zqVKlchqqmgS4fts8CAZbZR WsqH/AMdN51ll/9CK/kspOlDzU/GAJnLB1QFYngbkOZDlwhr6qk9WD39xTRjPc21hdAs 541g==
In-reply-to: <[email protected]>
References: <[email protected]cal> <[email protected]> <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
WSPR works with a noise bandwidth of 1.46Hz, and by virtue of the strong FEC, allows copy at a S/N IN THAT BANDWIDTH  of about +4dB.    This equates to -24dB S/N in 2.5kHz

10WPM morse has a noise bandwith of about 8Hz, and as you are only using audible / visual human interpretation needs probably a S/N of perhaps +6dB to +10dB depending on the operator's experience to decode perfectly.    That equates to about -20dB S/N in 2500Hz best case

So 10WPM CW is going to be at least 4dB worse, and possibly as much as 10dB  if operator experience is lower.

Andy  G4JNT

On 23 September 2017 at 12:00, Roelof Bakker <[email protected]> wrote:
Hello Joe,

The signal was much better last night.
I have attached an audio clip.

This is made with Linrad using a 10 Hz wide filter.
The keying sidebands are well within the filter passband.

I believe slow Morse, say 10 WPM, received with a 10 Hz filter will
achieve about the same signal to noise ratio as WSPR. In this case
this is 24 dB compared to a 2500 Hz SSB bandwidth.

Roelof, pa0rdt

The following section of this message contains a file attachment
prepared for transmission using the Internet MIME message format.
If you are using Pegasus Mail, or any other MIME-compliant system,
you should be able to save it or view it from within your mailer.
If you cannot, please ask your system administrator for assistance.

   ---- File information -----------
     File:  VO1NA20170923.mp3
     Date:  23 Sep 2017, 12:51
     Size:  248256 bytes.
     Type:  Unknown

<Prev in Thread] Current Thread [Next in Thread>