LF: Re: LF: 500 Permit emission’s bandwidth? EU and Global ??

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Mal,

Most would agree there is no place for data modes that take up lots of bandwidth, but 500kHz is an ideal band to experiment with narrow band data modes and some of the work being undertaken is very far removed from appliance operation.

73s
Roger G3XBM

On 6 May 2010 18:43, mal hamilton <g3kevmal@talktalk.net> wrote:

The majority of CW operators on LF/FMF will not exceed 100 hz bandwidth. 99.9% are sending at speeds of about 10wpm or less.

100 hz is about right on LF/MF where the total bandwidth of the permitted allocation is about 3 khz

also, as far as data modes are concerned all that is happening on LF/MF is bodging data modes meant for vhf/uhf applications and making a mess, ie the Appliance Operator approach

 

 

g3kev

 

 

----- Original Message -----

From: Rik Strobbe

To: rsgb_lf_group@blacksheep.org

Sent: Thursday, May 06, 2010 1:19 PM

Subject: RE: LF: 500 Permit emission’s bandwidth? EU and Global ??

Graham,

 

the document that gives us access to 500kHz says 100Hz bandwidth, but does not say how many dB's the signal has to be attenuated at these limits.

 

73, Rik  ON7YD - OR7T

 

---

Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Graham [g8fzk@g8fzk.fsnet.co.uk]
Verzonden: donderdag 6 mei 2010 13:30
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: 500 Permit emission’s bandwidth? EU and Global ??

Ok Many  thanks'  for the  reply's

 

From that .... next is :-

 

From the  data, I assume that  100  Hz is the  common  limiting factor for a  narrow  band  data transmission  that  could be used by all  who 'wanted'  to  use it  ?..(noted on the  cw keying  speed  ~ BW)

 

So if a  value of  100 Hz is  specified, what  is the  'presumed'  roll-off of the power in the said bands ?, assuming that  the  original  concept was based on CW operation , which by  definition 'has to' generate sidebands , there must be an assumed  tolerance ?

 

Q  would the deployment  of a  system that  could   defined as   125 hz bandwidth  ie 100 Hz with   +/-  12.5 Hz  overspill , cause  a  technical  breach  of the  regulations  or  be  viewed as  occupying  the  'allocated' bandwidth  for a  telegraphy transmission ? ,

 

Taking that  spectral measurements in the  10  Hz  region are  perhaps  starting to  test  even the  best equipment, the  area  is perhaps a  little  empiric ?

 

I use the  word  telegraphy, purposely to view/observe the  situation interims of the  licence  conditions and not on the  basis  of  'mode' which like  Liverpool  and Everton have there  own sub cultures  but are still  football  teams ..

 

Thanks 

 

Graham

G0NBD

 

 

 

 

From: Graham

Sent: Wednesday, May 05, 2010 10:39 PM

To: rsgb_lf_group@blacksheep.org

Subject: LF: 500 Permit emission’s bandwidth? EU and Global ??

500 Permit emission’s bandwidth?

 

Can any one indicated  what is the  permitted  ‘telegraphy’  bandwidth  of the various ‘new’ 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 ‘telegraphy’ 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  ?

 

Tnx – Graham

G0NBD

 

(I use the  word  ‘telegraphy’ as defined by the  ITU R V.662-3 ,  please no  reference to key clicks ! )

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