Re: VLF: 300 mA on 6470 Hz

[Paul Nicholson <vlf0403@abelian.org>]

> i see you changed the EbNaut calculator page again.
> There is a mode 16K23

Yes, will be available in the next upgrade which will be
ready soon (still testing).

> Characters: 1
> CRC bits: 0
> Coding 16K25A

You may as well use 8K19A or even 4K15A.

If you look at the big table at the end of

 http://abelian.org/ebnaut/ops.shtml

you can see there's no further improvement in success
rate for 6 bit payloads (1 char plus zero CRC = 6 bits).

The reason appears to be the payload is simply not long
enough to make full use of the longer constraint lengths.

> On Pauls side the SNR is equal, day and night.

Ah, not always.  We now have

 Night 2nd/3rd: -24.26 dB in 1Hz,  phase  34.9 deg
 Day 3rd:       -24.31 dB in 1Hz,  phase 100.1 deg
 Night 3rd/4th: -32.16 dB in 1Hz,  phase  24.3 deg
 Day 4th: ...

For some reason, the signal last night was about 6dB weaker.

--
Paul Nicholson
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