Pages

Pages - Menu

venerdì 29 novembre 2019

Trasmissioni VLF a 8 KHz


Tratto dal gruppo:  [VLF] Natural Radio & VLF Group

messages:
.
1a. 
VLF transmissions from IW4DXW
From: Paul Nicholson
Date: Thu, 28 Nov 2019 11:58:27 PST
Riccardo has sent two EbNaut coherent BPSK messages recently
from Ariano on 8270.003 Hz

start: 2019-11-26_21:00:00 UT
symbols: 15 seconds
length: 13 characters
CRC: 12 bits
coding: 16K21A

and

start: 2019-11-28_08:00:00 UT
symbols: 10 seconds
length: 20 characters
CRC: 24 bits
coding: 16K21A

Both messages decode here in Todmorden (distance 1413km),
with Eb/N0 +1.3dB and -0.4dB respectively.

At Cumiana (distance 371km), cross correlations reveals
the signals at Eb/N0 -18dB and -6.0dB, too weak to decode.

Bielefeld (845km) also too weak to decode with Eb/N0 -1.8dB
and -8.1dB. The 2nd transmission might have decoded but the
Bielefeld stream had one of its one-sample-backwards timing
breaks.

Each transmission lasts about 7.5 hours, the transmit power is
only a few uW so a very narrow bandwidth has to be used.

See http://abelian.org/ebnaut for info about the BPSK and
coding scheme. GPS timing is essential if you want to
receive these signals but that is very easy to set up.

--
Paul Nicholson



Nessun commento:

Posta un commento

I commenti sono aperti a tutti e sono soggetti insindacabilmente a moderazione.
NON SARANNO PUBBLICATI COMMENTI SE PRIVI DI NOME E COGNOME ED EMAIL.
IL SOLO NOMINATIVO RADIOAMATORIALE NON SOSTITUISCE IL NOME E COGNOME RICHIESTO.
Grazie.

Nota. Solo i membri di questo blog possono postare un commento.