Today, in the news, there was an announcement that Vaillant in the 
Netherlands has produced about 8000 Central Heating units (Vaillant HR 
Solide) between february and may 2006 which produce a lot of unwanted RF 
output when connected to a thermostaat (don't know the English word, neither 
the German) with the Open Term protocol.

It's a signal which can be received between 130 and 180 MHz, it's a clock 
sounding burst (which could be dis-synchronized when listening to a complete 
set of houses with all the same new type of heating) every second. It can be 
received up till 1,5 km from the units.

A lot of HAMs in the Netherlands (including me) have a lot of problems with 
those signals. I'm not sure if these units are sold in Germany also, but 
someone posted a message in my forum about a German HAM which was looking 
for the source of the noise he receives since a month or two.

Perhaps, with this message, other HAMs can be helped to locate the source 
of their problems. In the Netherlands, Vaillant is told by "Agentschap 
Telecom" to modify at least 90 % of the sold units, with a large amount to 
be payed if they don't succeed.
(Usenet)