Re: LF: QRM in Eastern Europe

[MarkusVester@aol.com]

Dear Dave and LF,

the prospect of 100 kW on 135.6 sure sounds like bad news! Even with a fairly "clean" carrier, I'd expect a few problems:

- at 600 km, it would be a signal of ~62 dBµV/m daytime, about 6 dB more at night. As this would be in the passband of my receiver, I'll have to do a redesign with 30 dB less gain :-( 

- with 340 Hz upward shift, the FSK bursts will splatter the into the amateur band, at least once every 10 seconds.

- at night, DCF 39 is contaminated by strong Luxembourg effect from various BC stations, with a modulation depth up to a few percent and sidebands reaching well into the band. Due to the inertia involved in the ionospheric heating process, they tend to be much more intense close to the carrier - 1 kHz can make a big difference.

- SXV are currently operating around 135.76 kHz FSK. They might feel inclined to evade QRM and move further up in frequency.

73, and have a beautiful summer

Markus, DF6NM
_____________________________________________________
In einer eMail vom 07.07.2006 16:48:38 Westeuropäische Sommerzeit schreibt daveyxm@googlemail.com: 

> German EFR (Europäische Funk-Rundsteuerung) are to broadcast control signals for utility companies on 135.6kHz from a site near Budapest. Although this looks like a potential cause of QRM in the band, the present sites at Mainflingen (129.1kHz) and Burg (139.0) are mostly plain carrier with occcasional bursts of data and are fairly benign. The English PDF, linked to above, shows the new TX service area but gives no other information. The German version quotes it as 100kW with a 280m mast, similar to Mainflingen in erp. 
>
> Info from HA6PX.
>
> -- 
> G3YXM IO92BK Birmingham UK