On 5 May 2010 at 22:39, Graham wrote:


> Can any one indicated  what is the  permitted  ~telegraphyTM  bandwidth 
> of the various ~newTM 500KHz  licences or  special  permits issued round
> the  EU and now the  rest of the  Globe ? 
> 
> I have the impression that 100 Hz is the maximum ~telegraphyTM
> transmission bandwidth, in some cases, eg , Belgium at 100 Hz .  Others
> appear to be some what wider or not defined ?.  
> 
> Norway  is CW only  ? what is the  Dutch  allocation ? Southern Ireland
> ? ... etc 

> Are  Beacons defined by  mode or  bandwidth  ?

It is important to differentiate between 'permitted' as a licence 
requirement or 'actual' bandwidth. The UK has never had bandwidth (for 
any mode) specified in its licence for any band, only a general note 
(note (a) on p. 14) that it should be the minimum that the technology 
and nature of transmission permit. My 500kHz NOV says nothing 
whatsoever about bandwidth (only spurious emissions), and for what it 
is worth at my request is for CW (A1A) only, ie no data. Norway I think 
is the only country with a permit that does stipulate 100Hz as a 
licence condition.

100Hz may be the 'actual' bandwidth of a typical CW signal at normal 
speeds - though will be higher at >60wpm or so, which I have not yet 
heard on 500kHz. The IARU Region 1 bandplans stipulate that the 
telegraphy only parts of the bands have a bandwidth of under 200Hz.

Also needs to be considered is the receiver bandwidth. Most CW ops will 
be using 300-400Hz filters, occasionally going to 100-200Hz to 
eliminate QRM problems. Much has been said about the very narrow 
bandwidth of some of the data modes, but this is largely irrelevant to 
the CW op who will still be using much wider filters. A point to be 
taken into account when deciding which parts of the bands to put CW and 
data (on any band, not just 136/500).

73 Dave G3YMC

http://www.davesergeant.com