Hi All,I'm starting (and possibly ending!) a new thread on DCF49 here since it was discussed below in a couple threads with unrelated subject lines (threads "171 kHz Morocco alert" and "Speaking of decoding LF signals"). I preface this post by saying it will likely be of only limited interest (indeed even that may be generous), but since I have new information I'll share it anyway.
I did a deeper dive into DCF49/129.1 kHz last evening (local Boston time) to answer my own question (posed in "171 kHz Morocco alert") about why DCF49 is listed as 129.1 kHz yet the dominant carrier is 0.18 kHz below that. Below are the results of my "investigation."
The main carrier of DCF49 is 0.17 kHz (not 0.18 kHz as I had said) BELOW the DCF49 listed frequency of 129.1 kHz, meaning the main carrier is on 128.93 kHz. The broadcast format consists of six 10 second cycles per minute of 9-9.5 seconds carrier followed by 0.5-1 second bursts of some kind of telemetry on 129.27 kHz. I previously referred to this as "hash" but my insight last night was that this "hash" had a precisely measurable frequency. 129.27 is 0.17 kHz ABOVE the DCF49 listed frequency of 129.1 kHz, so the lower carrier and higher telemetry frequencies are offset by 0.34 kHz, exactly centered on the DCF49 listed frequency of 129.1 kHz. There are zero transmissions on 129.1 kHz itself. My measured total 0.34 kHz offset exactly matches the 340 Hz FSK (frequency shift keying) offset listed in the EFR information kindly provided by Gedas in the 171 Morocco post thread. [For anyone interested in learning more about EFR, here's a link: www.sigidwiki.com/wiki/EFR_Teleswitch
Notably, about once a minute, there are longer, several second periods of telemetry on 129.27 kHz inserted into the repeating 10 second cycles. Since I can't decode (maybe someday!), I presume that the "regular" 0.5-1 second bursts are routine IDs, with the real "meat" of any power utility control transmissions occurring during the longer several second bursts. But that's only speculation.
Last night only DCF49 was audible here in the Boston area. But because they sound identical to my ear, I presume the same formatting as above applies also to the other 2 EFR stations: HGA22/135.6 kHz and DCF39/139.0 kHz.
Finally, here's a link to a Wikipedia page about the Mainflingen, Germany transmitter site: en.wikipedia.org/wiki/Mainflingen_longwave_transmitter. At the bottom of that page there are a couple links to Google Maps where you can see the actual antenna towers by satellite view (the site also transmits DCF77 on 77.5 kHz).
73 to all, Bruce WA1HGJ