On 23-May-10 8:36 AM, Joe Subich, W4TV wrote:
>
> WSJT is a linear mode (multiple tone frequency shift keying) - it
> does not tolerate clipping/compression well. Since the 3-500 is
> specified for for 400 mA MAXIMUM you are running it well into
> compression (current starvation).
Sorry Joe, but that is wrong. WSJT is *ONE TONE AT A TIME*. It can and
does not only tolerate Class C amplifiers, but thrives on it! I run my
2x4CX250B's class C at 1100 watts output on 2 meter EME JT65B with no
issues at all.
K1JT even mentions in the instructions for WSJT that none of the WSJT
modes require a "linear" amplifier. Now don't confuse WSJT FSK modes
with that crummy PSK31 crap that cannot tolerate even a little
distortion in the amplifier without causing trouble.
BTW, WSJT JT65 modes as used for EME are true 40% duty cycle, IE 48
second out of every 2 minutes full carrier power followed by 72 seconds
of standby and/or RX.
I have run a SB-220 converted for 6 on EME at 800 watts output (CW
position). It worked OK as long as I operated it with the outside
cabinet removed. Even so, I was really happy when I got the GS-35B going
with it's 200 pound power supply!
73,
Larry - W7IUV
DN07dg - central WA
http://w7iuv.com
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