> ==========================================
> Quoting from Ken Bourne Mon, 8 Apr 2002 11:28:27
>
> http://www.n9vv.com/w6hk.html
>
> "Regarding RF power, the ORION's output will be a ROBUST 100 watts, 100% duty
> cycle, into ANY SWR! A higher output is not possible, due to the 13.8 Vdc
> power supply and choice of output device for optimum HF operation. Regarding
> HF-only operation (no 6 meters), that decision was based on the type of
> transmitter output stage for optimum HF operation (a different output device
> would be more costly, and would compromise the overall HF performance) . . . "
While the quoted material above stresses that the finals can deliver 100
watts, 100% duty cycle into ANY SWR, I wonder what the IP3 and IP5 numbers
are for 100 watts into nothing more extraordinary than a 2:1 SWR, i.e., a
100 ohm load instead of a 50 ohm load.
It is good that the finals will not be damaged by such operation, but what
happens to the quality of the signal under those conditions? How do the
intermodulation product magnitudes compare with those under normal load
conditions? The same? Worse?
The wording of the quotation states that 100 watts will be output into any
SWR. "Any SWR" presumably includes such extreme operating conditions as
short or open circuit loads. Does the spec mean that the finals will
deliver 100 watts into a short circuit? Or simply that the finals will
survive being connected to a short-circuit load? Surely only the latter . .
.
I don't believe that I have seen any intermodulation distortion product
data in the Orion specs that have been published thus far . . . while these
numbers do not provide a complete definition of the transmit audio quality
of a transmitter, their values do offer a strong clue, especially when
measured under a variety of realistic load conditions.
Since the transmit occupied bandwidth of the Orion will be quite large
compared to other transceivers, it would seem to be a requirement that the
finals provide very low IP3 and IP5 numbers if it is to be the basis for a
"hi-fi" SSB station.
73/72/oo, George W5YR - the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121 Kachina 505 DSP #91900556 Icom IC-765 #02437
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