[Fwd: LF: Reading between the lines]

[Andre' Kesteloot]

Peter Dodd wrote:

> In the past I have complained a lot about Loran, which is quite
> strong here on the South Coast.
> Viewing the band using Spectogram shows that within the bandwidth of
> the narrowest CW filter there may be 18 or 20 Loran sidebands. Each
> individual sideband is not that strong but is about the same as an O
> report  slow CW signal.
> Some time ago someone suggested (either G4JNT or G3PLX) that there
> should no problem in working between these Loran sidebands and
> although I did not believe it at the time I now know that it is easy
> - I have been doing it for the last couple of weeks.
>
> The following is a description of how the band appears here when
> clear of evening QRN
> A frequency quoted as .703 means 137.703kHz.
>
> About 8 Loran lines close together   .772 - .800
> Clear band                                      .769 - .771
> Clear band                                      .761 - .763
>
> 2 strong Loran lines and noise          .755 - .758
> Big carrier at .745 with upper sideband noise to .754. (about S6 - 7
> in fast CW terms)
> Lots of weaker Loran sidebands      .709 - .742
> Clear band                                      .695-.703
> Clear band                                      .681 - 690
> Clear band                                      .667 - .675
>
> Frequency bands not quoted have Loran sidebands. The problem with the
> Loran is that many of the sidebands are pulsed so that they look like
> slow CW signals although I have got to know them now.
>
> I worked  Peter, DJ8WL OO this evening (1645UT). On peaks his signal
> was strong enough to be audible using a narrow filter, other times he
> was down in the noise. Rain static closed in at the end of the QSO.
>
> I copied Dave's PSK31 tests which made some pretty pictures on Gram.
> I measured the centre frequency as .653 with sidebands extending to
> .671 and .637. Additional single frequency sidebands occured at .702
> and .608. (I have saved the WAV files if you want them Dave)
>
> --
> Regards, Peter, G3LDO
>
> <g3ldo@zetnet.co.uk>