Bonnie's detailed explanation looked reasonable to me.
I often use the NCDXF propagation beacons and have rarely heard them
QRM'd by digital signals.
73,
Dave, AA6YQ
--- In digitalradio@yahoogroups.com, John Bradley <[EMAIL PROTECTED]>
wrote:
>
> In other words Tony, despite decades of tradition of having the CW
beacons on 14100, the ALE users don't give a rat's butt for anyone
except a small number
> of ALE users.
>
> and the only reason they are doing this is because they can.
>
> John
> VE5MU
>
>
>
>
> Subject: [digitalradio] 14100.5 kHz USB - ALE Channel Bandwidth,
IARU Beacon Guardband
>
>
> > Tony KT2Q wrote
> >
> > Bonnie,
> >
> > Not sure if it's been said before, but the
> > 14100.5khz ALE data channel seems awfully close
> > the NCDXF beacon frequency on 14100.0.
> >
>
> Hi Tony,
>
> Yes, it is has been covered before in HFLINK group, and via direct
> communication with IARU Region frequency coordination. I will
gladly
> cover it again for the benefit of new ALE operators and the
> digitalradio group. This ALE channel has been in use for a long
time
> and there have been no complaints or problems.
>
> The 14100.5 kHz USB ALE channel has been frequency coordinated
with
> the IARU Regions, including IARU Region 1, which has the widest
beacon
> guardband (+/-1 kHz) for the IARU-NCDXF beacon at 14100.0 kHz CW.
IARU
> Region 2 and IARU Region 3 both have lesser (+/-500Hz) guardbands
for
> the IARU-NCDXF beacon CW channel. The ALE channel conforms to the
more
> strict IARU Region 1 requirements.
>
> All amateur radio ALE channels are based upon accurate calibration
> within +/-20Hz and standard fixed audio frequencies. The ALE
system
> inherently fails to operate if these rigid standards are not
followed.
> All ALE operators are admonished to operate with the highest
technical
> standards.
>
> The lowest tone of the 8FSK ALE signal is exactly 750Hz and the
> highest tone is exactly 2500Hz. For the 14100.5 kHz USB channel,
it
> translates to RF frequencies:
> 1. Lowest tone = 14101.25 kHz
> 2. Highest tone = 14103.00 kHz
>
> The 1750Hz "bandwidth" for the 8FSK signal has a spectrum that is
> widened slightly (+/-200Hz) by the transition of the shifting of
the 8
> FSK tones at the 125 baud (symbol) rate. The -23dBc bandwidth of
the
> RF spectrum of the 8FSK ALE signal is 2150Hz and the low end is
> equivalent to an audio frequency of 550Hz.
>
> 14100.5 kHz + 550Hz = 14101.05 kHz
>
> Beacon guardband clearance bandwidth:
>
> Top edge of IARU Region 1 beacon guardband = 14101.00 kHz
>
> Bottom edge of 14100.5 kHz USB ALE Channel = 14101.05 kHz
>
> Channel Edge to Beacon Guardband Edge Clearance = 50Hz.
>
> Maximum allowed calibration frequency error = 20 Hz.
>
> Total clearance including calibration error = 30 Hz.
>
> The ALE channel meets the strictest IARU Region 1 recommended
> guardband by 30 Hz and meets the less strict IARU Region 2 and
IARU
> Region 3 by 530 Hz.
>
> 73---Bonnie KQ6XA
>
> .
>
>
>
>
>
>
> --------------------------------------------------------------------
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