There has been recent discussion about power and the difference it will
make. Unless you have studied this before you may be amazed at what sort of
difference power can make to RTTY decode error rate.
A received signal with decode errors cause by noise and not by propagation
effects like selective fading, flutter etc has a character error rate of
10%. By increasing power by 2dB, e.g. 100 watts to 160 watts the error rate
will drop to about 1% or for most amateur purposes perfect copy.
So changing that long run of RG58 coax to RG213 or putting the antenna up a
bit higher or turning the power up from 50 watts to 100 watts can
significantly improve copy at the far end. Better copy at the far end = more
QSOs.
I note many run their 100 watt rigs at around 50 watts because they think
the rig cannot take the full power on RTTY. I have news for you all the rigs
I have ever had I have run at full power on RTTY without ever having blown
the PA devices. The typical 13.8v 100 watt AB class PA has similar device
dissipation at 50 watts out as at 100 watts out. Some PAs will have less
dissipation at 100 watts than 50 due to the PA being in gain
compression(saturation). The PSU will be supplying more power but again all
of the commercial 13.8v SMPSU I have used have worked perfectly at 100 watts
output.
73 David G3YYD
_______________________________________________
RTTY mailing list
RTTY@xxxxxxxxxxxxxx
http://lists.contesting.com/mailman/listinfo/rtty
|