[Lowfer] Loran Lines

[John Andrews]

Jay's email this morning caused me to look at his screenshot as well as 
what I could see from here in MA. The current Loran operation from 
Wildwood, NJ has a group rate of 89700 microseconds. This produces 
sidebands at 5.574 Hz intervals (1/2*GRI). Back in the bad old days when 
a bunch of Loran-C chains were in operation, this gave a whole forest of 
sidebands through the 2200 meter band and beyond. To give you newer 
folks an idea of how much fun it was, see this table:
http://lwca.org/library/reference/LORAN/loran3.htm

That list is still valid, but only for what was the 8970 Great Lakes 
operation. Looking at Jay's screenshot, most of the lines appear to 
correlate with Loran sidebands. I looked around 137.780 kHz here in MA, 
and found the expected lines as well. I do have a number of other stable 
lines in this band that don't correlate with Loran.

Not all Loran lines are created equal. Some are brighter than others. 
I've always guessed that it had to do with the pulse shape down at 100 
kHz. At this distance (280 miles) some of the lines are lost in the 
noise, while others are quite bright.

Now, the fun part of all this is that during some of the earlier tests 
from Wildwood, lines were not visible here in MA. This is probably just 
a power output thing, as that may be one of the variables they are testing.

Also, keep in mind that the present tests are being done by a company 
seeking to demonstrate the usefulness of e-Loran. There is no certainty 
that this service will ever go full-time, or what sites might be used. 
Europe appears to be abandoning Loran entirely (including e-Loran 
experiments), judging from some recent messages on the RSGB LF Reflector.

John, W1TAG