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LF: Re: Re: 136 khz LF

To: [email protected]
Subject: LF: Re: Re: 136 khz LF
From: "hamilton mal" <[email protected]>
Date: Sun, 19 Oct 2003 08:47:13 +0100
References: <[email protected]> <[email protected]>
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----- Original Message -----
Sent: Sunday, October 19, 2003 12:06 AM
Subject: LF: Re: 136 khz LF

You can't possibly mean -5dBm.
 
Even if propagation were line of sight, at 200km distance (near enough between you ?)  Free space loss = 32.4+20LOG(f.d)  [MHz, km]  = 61dB.   EIRP max 30dBm so max power received assuming you antenna were 100% efficient (!!!!)  could only be -31dBm.
 
I don't think there can be a propgation mechnism at these freqs where path loss can be less than line-of-sight.  Unlike ducting on microwave paths.
 
Using speclab this is what was indicated. Nothing calibrated. Relative measurement signal above noise floor 55 db.
I expect to be really meaningful the system needs to be calibrated. Next time I will try the calibrated LEVEL METER
The signal was very strong, likwise M0BMU is also very strong. Large dog bones across the screen !!!!!!
 
Andy  G4JNT
----- Original Message -----
Sent: Saturday, October 18, 2003 2:58 PM
Subject: LF: 136 khz LF

Band quiet today at my observation times. Did see G3YXM on QRS very strong signal at -5 dbm and 55 db signal above noise floor.
73 de Mal/G3KEV
 
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