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
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