Re: LF: HGA22?

[Markus Vester <markusvester@aol.com>]

Hi Laurence,

 

good to read that you are all well after the shake!

 

Today I briefly looked at the HGA mark (idle) frequency and got 135430.02 +- 0.01 Hz. The space frequency (nominally 136.17 kHz) is more difficult to measure as it only occurs for short intervals during the telegram bits.

In the summer of 2012, we considered using HGA22 as a frequency reference for Chris' YO/4X1RF LF-grabber in Bucharest. We overcame the spread from the semi-random telegram phase shifts by measuring at the 14th audio harmonic, exploiting the fact that the 14-fold phase excursion during a signal bit happens to be very close to an integer number of cycles.

 

Attached is an 8-day measurement, referenced to my local LPRO Rubidium standard. The HGA transmit frequency seemed to be 135430.0215 Hz, with a couple of mHz diurnal variation apparently caused by temperature effects at the transmitter site. During the day, the relatively small scatter demonstrates frequency transfer accuracy on the order of 1e-10, wheras at night due to multipath skywave it is no better than 1e-8.

 

The recent measurement seems to be in agreement with the old one, indicating that the idle frequency has not changed.

 

All the best,

Markus (DF6NM)

 

-----Ursprüngliche Mitteilung----- 
Von: Laurence KL7 L <hellozerohellozero@hotmail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 24 Jan 2016 8:09 pm
Betreff: LF: HGA22?

Morning all -
 
Can I get the current measured mark/space HGA22 beacon circa 135.6 please - signals are pretty weak and Im not sure whether its just prop or they've "moved" a tadge. 
 
 Sigs from DCF39 138.8305 are pretty weak over the pole this morning - but window
http://kl7l.com/LF00000.jpg is still open when available showing 136/137 and DCF39 windows
 
 
Earthquake at 1030z
Parts of Alaska clearing up after the recent Earthquake - at least one house burnt down -  here its a matter on straightening pictures and picking up stuff off floor. Nearly pushed me out of my bed! Felt like an old Southern railway trail journey between East Croydon and Victoria...
 
 
Laurence KL7L

           

HGA_frequency_offset_120816_2007.png
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