Bartg Sprint 75

[Claude Du Berger]

Hello Group.
June 12 is the Bartg Sprint 75 (test) Contest.
At this speed, what is the best filter to use and can we
still use the so sharp Dual PB?

Claude Du Berger VE2FK
[hidden email]

http://www.contestgroupduquebec.com/
http://sites.google.com/site/va2upcontesting/Home
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[KK7P]

> June 12 is the Bartg Sprint 75 (test) Contest.
> At this speed, what is the best filter to use and can we
> still use the so sharp Dual PB?...
I just read the rules.  The shift is not specified, only the data rate
as being 75 bps rather than 45 (or 45.45) bps.

The K3 DualPB filter for AFSK or FSK mode should work fine at this data
rate.  The sidebands will be slightly wider due to the faster keying
speed, so a 200 Hz roofing filter is probably a little tight.

73,

Lyle KK7P
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[Joe Subich, W4TV-4]

Necessary bandwidth for 75 baud 170 Hz shift RTTY is
about 360 Hz - approximately (75/2 * 5 + 170).  A 400
Hz roofing filter is probably close to optimum for
75 baud RTTY.

Note - 200 Hz is theoretically too narrow for even 45.45
baud RTTY (necessary bandwidth approximately 280 Hz).

73,

    ... Joe, W4TV

On 5/31/2010 9:38 PM, Claude Du Berger wrote:
> Hello Group.
> June 12 is the Bartg Sprint 75 (test) Contest.
> At this speed, what is the best filter to use and can we
> still use the so sharp Dual PB?
>
> Claude Du Berger VE2FK
> [hidden email]
>
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[Claude Du Berger]

Thanks Lyle and Joe.
I am all set. Tested this morning with a friend, 75 baud.
400Hz filter plus Dual PB at this end and all was working well
even with low signal in the noise.

73, Claude
  ----- Original Message -----
  From: Joe Subich, W4TV
  To: Claude Du Berger ; Elecraft Reflector
  Sent: Monday, May 31, 2010 11:09 PM
  Subject: Re: [Elecraft] Bartg Sprint 75



  Necessary bandwidth for 75 baud 170 Hz shift RTTY is
  about 360 Hz - approximately (75/2 * 5 + 170).  A 400
  Hz roofing filter is probably close to optimum for
  75 baud RTTY.

  Note - 200 Hz is theoretically too narrow for even 45.45
  baud RTTY (necessary bandwidth approximately 280 Hz).

  73,

      ... Joe, W4TV

  On 5/31/2010 9:38 PM, Claude Du Berger wrote:
  > Hello Group.
  > June 12 is the Bartg Sprint 75 (test) Contest.
  > At this speed, what is the best filter to use and can we
  > still use the so sharp Dual PB?
  >
  > Claude Du Berger
  > [hidden email]
  >
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