that URL may have got mangled; I think it is this article
Unfortunately I looked out of curiosity at one of the open source router firmware sites and its documentation (at least the English version) very unwisely states “it is OK to shut off DFS even if you live in a coastal area; inteference is unlikely”.
That might mean your WLAN works fine but unless you have a bench full of Rohde & Schwarz / Agilent kit to check the signal levels (and also know exactly what you should be looking for) you are unlikely to know if your countries national weather services (and possibly that of your neighbours) is now seeing stuff like this upon their screens.
This is from the weather service of Austria. The WLAN signal is across the border in Slovenia – possibly from Podljubelj (DE: Sankt Anna) which appears to be the nearest area with any significant population.
Although likely to be completely unintentional (looks like a business grade point to point link with a directional antenna) it causes Angst to both countries air traffic control as they can’t monitor the Weather.
There is a lot of other stuff in the same frequency band (much of it defence related or for specialist civil aviation and maritime purposes) which is why DFS was implemented in the first place.
UK Ofcom is currently looking at allowing more 5GHz channels to be used (there is a big gap in the allocation that serves as a guard band between WLAN and radars) but would require DFS to be activated at all times.
Where I live I can see the tidal River Orwell from my window and its a major North Sea shipping route plus the civil flight path for EGSS (London Stansted) and EGLL (London Heathrow) and many military and public service aircrafts – trying to use the top end of the band on 5GHz unsurprisingly often results in the access point being knocked back by a radar and ending up on the same channel as the neighbours stock Virgin Media / Talk Talk equipment (and doesn’t give any advantages in using the lower block of channels anyway).
Its easy enough if you don’t put some thought into how RF works (or have experimented with other transmitters) and live in a small house to end up sending your signal 0,5km down the street (cutting across everyone else on the same channel) and yet end up with a black spot in your own building – which is why the FCC and other Communications ministries worldwide initially tried to make it difficult to change the antennas and RF settings on domestic WLAN equipment .
