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Re: LF: bandwidth ?

To: <[email protected]>
Subject: Re: LF: bandwidth ?
From: "Graham" <[email protected]>
Date: Thu, 6 May 2010 22:05:40 +0100
Importance: Normal
In-reply-to: <BF4A524700075746A6467658DFC7102C3E8DF194F3@ICTS-S-EXC2-CA.luna.kuleuven.be>
References: <BF4A524700075746A6467658DFC7102C3E8DF194F3@ICTS-S-EXC2-CA.luna.kuleuven.be>
Reply-to: [email protected]
Sender: [email protected]
Thanks Rik,
 
See  the  post -  re  New Mode , Jose has  undertaken to  code a  100 Hz qso  mode based on the  existing ros systems  , not  as  fast as psk , but will  comply  with the  100 Hz  band  restrictions and offer  enhanced  phase and s/n  performance ... may be  125 hz could of been  used , but with the  on going 'flap' , it was better  to  simply  reduce the  bw to  the allowed limit !  (but not  simply  for  Jose .. needs quite a  lot of  re-work on the  code)
 
Hopefully  it will  ready  to test in a week or so
 
73- G ..
 
 

Sent: Thursday, May 06, 2010 6:32 PM
Subject: LF: bandwidth ?

Graham,
 
next question: how to define bandwidth (-3dB, -30dB, ... edge frequencies) ?
As I couldn't find a definition in our national ruling I had a look at "higher levels".
The only thing I found was in the IARU-Region 1 HF managers handbook:

 

1.153 occupied bandwidth: The width of a frequency band such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage ı/2 of the total mean power of a given emission. Unless otherwise specified in an ITU-R Recommendation for the appropriate class of emission, the value of ı/2 should be taken as 0.5%.

 

Taking this definition it depend on the power distribution of the signal. That makes sense, but is very hard to measure.

 

73, Rik  ON7YD

 

Van: [email protected] [[email protected]] namens Graham [[email protected]]
Verzonden: donderdag 6 mei 2010 15:08
Aan: [email protected]
Onderwerp: Re: LF: 500 Permit emission’s bandwidth? EU and Global ??

Thank you  , Rik,
 
From that  , its possible that  the  other  permits are  similar
 
Ok Tnx - G .

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: [email protected] [[email protected]] namens Graham [[email protected]]
Verzonden: donderdag 6 mei 2010 13:30
Aan: [email protected]
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
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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