On Wednesday, Apr 2, 2003, at 20:45 US/Pacific, K4SB wrote:
>> If the OMNI V is like the OMNI VI+ it keys FSK "upside down"
>
> Don't know about the V, but the VI definitely does NOT key "upside
> down" on FSK.
I have used the Omni V, Omni VI, FT-990 and FT-1000MP on RTTY.
Ed is correct.
The two Omni rigs (exactly the same interface between Omni
V and Omni VI) key correctly, based on voltages at the RCA
connectors and specs from the rigs' manuals.
A KAM, for example, uses the same interface polarity as the
Omni, and is compliant with the Omni.
On the other hand, both the Yaesu rigs (again same interface
between 990 and 1000MP) keying are reversed compared to the
Omni.
If you are using a KAM/Plus/98, you need to either set the
KAM to "FSK reverse," or set the Yaesu rigs (top panel switch
on FT-990, menu setting on the FT-1000MP) to reverse to put
out mark on the higher carrier on the RF bands (i.e., lower
receive audio tone on an LSB receiver).
If you'd added a common emitter transistor (or common drain
FET) driver in the FSK keying line, the driver will of course
reverse the keying polarity. But, when measured right at the
RCA connector of the Omni, the polarity is absolutely correctly
documented in the User Manual.
73
Chen, W7AY
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