Gary, LF,

 

Anthorn is designated "6731Y", which says that it is running a pulsegroup repetition interval (GRI) of 6731 carrier periods (ie. 67.31 milliseconds). There is a phasecoding scheme that alternates phases on every second pulsegroup, thus the periodicity is really 2x GRI. So all the spectral lines are precisely at multiples of 

 100 kHz / 2 / 6731 ~ 7,4283167434 Hz.

Lessay is running dual-rated on both 6731 and 7499, so it has an additional set of lines with 6,6675556741 Hz spacing. During the night, you might also see much weaker lines from Ejde on GRI 9007.

 

Best 73,

Markus (DF6NM)

From: Gary - G4WGT

Sent: Friday, October 21, 2011 4:37 PM

To: LF Group (RSGB)

Subject: LF: Anthorn UK, Loran.

Hi All,

Can someone give my the formula for calculating the spot frequencies of Loran as generated by Anthorn, UK.

I am testing a uHz SpecLab display using Stefan's 137kHz soundcard receiver & I am seeing lines which don't match with my old spread sheet calculator. I need to know if they are Loran or something generated locally. The lines are very straight so its difficult to judge.

Or, if anyone has a better idea I am open to suggestions.

73, Gary - G4WGT.