In message <[email protected]>, "J. Fors
ter" writes:
>I remember reading somewhere that the envelope of the LORAN pulses was
>shaped to reduce the transmitted BW.
The envelope is designed for two things: sensible BW and ease of
production. There is some math musing about it in the Radiation Lab
book.
>Does anybody have a reference for that, and relatedly, what does the BW of
>the antenna have to be? Typically, loops are about 90 KHz to 110 KHz, but
>can that be narrowed down?
In principle you can make it as narrow as you want, and compensate
for the resulting pulse-shape distortion in your receiver.
Going much wider than 30kHz (85-115kHz) usually results in more
interference from CW signals than improvement to the loran signal.
You can see a typical power spectrum at the bottom of this page:
http://phk.freebsd.dk/loran-c/Antenna/
Poul-Henning
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[email protected] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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