[PVRCNC] R R on AM radio

[Jim K4QPL]

Hi Tom,

I can't hear anything. Are you sure you're hearing "R" and not "LE"?  Is it 
true cw or tone modulated AM? The outer marker for the left hand runway ILS 
at RDU is about 2 miles west of me and comes in S9 at 350khz. The subrx on 
my Orion II goes down to 101khz so I can pick it up easily. I didn't hear 
anything else tonight in that VLF band except broadcast band images. LE is 
an AM signal, tone modulated to identify its location near Leesville. You're 
just another couple miles from me so you should be able to hear it if you 
have a radio that tunes down there.

Regardless, my guess is that you're hearing a heterodyne product or some 
other spurious signal from one of the ILS (Instrument Landing System) 
beacons for RDU. It wouldn't be direct at that freq and 570 is too close for 
an image as that would put the primary signal right down at 115khz for a 
455khz IF. I don't hear anything there either. While the subrx in the Orion 
isn't very good, it would probably screen out anything not excessively 
strong that wasn't a primary frequency of 570. Those beacons are low power 
and are aimed straight up so you would probably need to be pretty close.

Don't have any other ideas.

73 and HNY,

Jim, K4QPL


The other remote possibility would be
----- Original Message ----- 
From: <n4tl2 at earthlink.net>
To: "pvrcnc" <pvrcnc at mailman.qth.net>
Sent: Sunday, January 02, 2011 4:00 PM
Subject: [PVRCNC] R R on AM radio


> Hi everyone,
>
> I have noticed that when I listen to 570 AM at night I will hear, in Morse 
> code to letter Rs sent together about once a minute or so. I have heard 
> this about 9 PM a few days ago. It sounds like a different station sending 
> the Rs because if 570 is too strong I don't hear the Rs.  Anyone have any 
> idea what the Rs are for?
>
> Tom, N4TL
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