Re: LF: Re: Luxembourg

[Markus Vester <markusvester@aol.com>]

John and LF,

what the ICM products look like in a spectrogram of course depends on the FFT resolution. The narrow events were created by test tone modulation on the broadcast transmitter (probably 225 kHz but I didn't listen). Such tones are often transmitted some time after local midnight for a couple of minutes. The sub-Hz line linewidth was probably defined by a slight audio frequency drift of the tones, in addition to the  0.1 Hz broadening of the DCF /HGA carriers themselves due to the FSK telegrams.

The more typical musical tones create strips and patches that are several Hz to tens of Hz wide. So they have a somewhat similar appearance, but on a wider frequency and faster time scale. You can often see them on the fullband panel of my colour DF grabber - red above HGA22 (135.43 kHz) and purple below DCF39 (138.83). However with millihertz resolution (e.g. QRSS-60), they mostly appear as temporarily increased noise.

73, Markus

-----Ursprüngliche Mitteilung----- 
Von: John RABSON <john.rabson@wanadoo.fr>
An: rsgb_lf_group@blacksheep.org
Verschickt: Do., 15. Jan. 2009, 10:30
Thema: Re: LF: Re: Luxembourg

Markus, Lubos,

Are these light-coloured patches a typical signature of this effect?  I get quite=2
0a lot of them here.

John F5VLF

*********** REPLY SEPARATOR  ***********

On 15/01/2009 at 03:32 Lubos OK2BVG wrote:

>Hello Markus, LF!
>Many thanks for your info about Russian Loran (GRI 8000), it´s this!
>
>Here is my picture of Luxembourg effect in JN88KS. Very strong signal.
>
>Lubos, OK2BVG
>
>**************************************************
>
>> From: markusvester@aol.com
>> To: rsgb_lf_group@blacksheep.org
>> Date: Thu, 15 Jan 2009 01:22:41 +0100
>> Subject: LF: Re: Luxembourg
>> 
>> .. this is the cross modulation signature on the RN3AGC grabber. The
>pattern was also visible on F1AFJ's screen. - 73, Markus
>> 
>> ----- Original Message ----- 
>> From: "Markus Vester" <markusvester@aol.com>
>> To: <rsgb_lf_group@blacksheep.org>
>> Sent: Thursday, January 15, 2009 12:52 AM
>> Subject: LF: Re: WSPR beacon on 136kHz, Luxembourg
>> 
>> 
>>  The band is fairly quiet tonight. Twice for a few minutes around 23:23
>and 23:33, there were strong Luxembourg sideband carriers
>>  simultaneously on both HGA and DCF. They were apparently caused by a
>1054 Hz sinusoidal modulation test tone (sidebands at 136.484,
>>  75 uV/m and 137.776 kHz, 13 uV/m). There was also a -20=2
0dB second
>harmonic component (137.538, 6 uV/m and 136.722, 1.5 uV/m), due 
>> to
>>  the square-law charasteristic of the heating effect.
>> 
>>  Kind regards,
>> Marksu, DF6NM
>>  
>
>_________________________________________________________________
>Pozvi své přátele z Facebooku a Hotmailu do Messengeru!
>https://www.invite2messenger.net/Default.aspx

---

AOL eMail auf Ihrem Handy!Ab sofort können Sie auch unterwegs Ihre AOL email abrufen. Registrieren Sie sich jetzt kostenlos.