[Lowfer] Spectrum Lab as LORAN receiver

[Stewart Nelson]

Hi John and all,

Chain config of 9610 is here:
http://www.megapulse.com/pix/chain/9610.gif

in AM: http://www.scgroup.com/ham/loran4.gif

In SSB: http://www.scgroup.com/ham/loran5.gif

In AM, you can see M, V, and W.  In SSB, X and Y
are also evident.  

With AM, of course, once the signal drops below
the noise, the detector output falls very rapidly.
IIRC, it's as the square of the signal strength.

If you are just trying to look at the local chain,
AM is much simpler (with this tool) and offers
adequate sensitivity.

I have been using the SSB mode, because it's much
closer to what a "real" propagation monitor would do.
Software written for the purpose would have much
greater sensitivity, because:

1. It could integrate over many minutes instead of
   seconds.

2. It would coherently combine the 8 or 9 pulses
   of a group, and the A and B groups.

A sophisticated version would gain additional
sensitivity by:

3. Blanking and/or canceling interference from
   local chains.

4. Combining the rates from dual-rated stations.

5. Having a decent impulse noise blanker.

IMHO, there is at least 30 dB still on the table.

73,

Stewart KK7KA

----- Original Message ----- 
From: "John Andrews" <w1tag@charter.net>
To: <lowfer@mailman.qth.net>
Sent: Thursday, January 01, 2004 5:37 PM
Subject: Re: [Lowfer] Spectrum Lab as LORAN receiver


> Stewart,
> 
> What would be the advantage to your method vs. leaving the receiver in AM
> mode and analyzing the L1 signal?
> 
> John A.