11 ms·
DCF77 surely cannot be that bad indoors on the Continent? When living at what was then often quoted as the extreme fringe of the coverage area - Trondheim, Nor
by lb1lf 9y ago
DCF77 surely cannot be that bad indoors on the Continent?
When living at what was then often quoted as the extreme fringe of the coverage area - Trondheim, Norway, on 63,5 degrees of latitude - I had reliable coverage as long as the clocks were kept in window sills (hence, effectively outdoors)
However, just moving down to my current home (on 62 degrees, or -roughly speaking- 11% closer to the transmitter site), I now have reliable coverage everywhere (granted, in a wooden house - but the DCF77 alarm clock in the basement synchs every hour, too)
- gpvos 9y agoI've found that antenna orientation matters, even in the Netherlands which is much closer to DCF77 (concrete house).
- c3833174 9y agoYes, it needs to be perpendicular to the direction of frankfurt for best results You can find more details in the second page of this datasheet https://www.gemischtwaren-haendler.de/shopdateien/3942_1.pdf https://www.gemischtwaren-haendler.de/shopdateien/3942_1.pdf
- gpvos 9y agoMore importantly, you would need to know how the antenna is oriented within the enclosure of your clock. I'm pretty sure that that wasn't mentioned in the manual of the one I bought.
- IronBacon 9y agoCitizen, the Japanese watches maker, offered a passive (without batteries) "enhancer" for their AT series, IIRC was a ferrite block where to put the watch, I think I've seen a photo. Or one can use a PC to transmit the DCF77 signal locally (it could be illegal) to a clock using a pair of headphones, I've seen at least a couple of examples but never tried them. Edit: found the photo http://forums.watchuseek.com/f17/possible-method-improve-atomic-time-syncing-1305322-2.html#post10570034 http://forums.watchuseek.com/f17/possible-method-improve-ato...
- Piskvorrr 9y agoBeats me - I'm within reasonable driving distance to the antenna (one border away), yet clocks fail to acquire signal unless outdoors/directly at a window. Just a bad coverage area, I guess.
- josu 9y ago>11% closer to the transmitter site This is completely outside of my area of expertise, but doesn't the radio signal strength decrease exponentially? So that last 11% could be a big deal?
- Piskvorrr 9y agoInverse square, so you're in the vicinity of being correct: https://en.wikipedia.org/wiki/Inverse-square_law https://en.wikipedia.org/wiki/Inverse-square_law
- muxator 9y agoQuadratically. Line-of-sight attenuation of an EM wave in the empty space is quadratical, whilst - for example - attenuation of an electrical signal in a wire is exponential. Obviously this is a super simplification...
- josu 9y agoOh, that makes sense. Thanks for your explanation, good enough for now :)