[TenTec] cw creation

[Ken Brown]

Sounds like an interesting rig.

 If the 1 kHz sine wave has some harmonic content (it is not perfectly 
sinusoidal), this rig could generate as many as five signals:

1) the desired signal 1 kHz above the indicated frequency
2) the second harmonic of the tone generator would still be inside the 
SSB filter and would be a signal 2 kHz above the indicated frequency
3) the "carrier" which should be well suppressed, but often is not
4) the opposite sideband of the desired signal, 1 kHz below the 
indicated frequency
5) the opposite sideband of the second harmonic of the tone generator, 
2kHz below the indicated frequency

3, 4, and 5 are supposed to be greatly suppressed if the rig is aligned 
properly. Number two depends on the purity of the tone generator.

If it is a phasing type SSB rig that doesn't use a sideband selecting 
filter, there could be more harmonics from the tone generator, each 
another 1 kHz further from the indicated frequency, and more on the 
opposite sideband too. Phasing type SSB rigs do get out of alignment and 
the opposite sideband rejection gets poorer, as well as the carrier 
rejection.

In many cases I think it would be easier to use another BFO crystal and 
unbalance the balanced mixer. There are fewer things to go wrong.

Yes, using the tone modulated SSB transmitter method can be done and has 
been done. This is not exactly "a great many rigs", but there are no 
doubt more. Do you know of some more?

>I have an ex-embassy commercial transmitter, the Sunair GSE-924 that
>injects a 1 kHz sine wave while in USB mode to produce CW.  This is a
>pretty impressive rig, no cooling fan 30 w AM, 100 SSB and 100 CW.  I
>have an idea that it was not much used in the CW mode.  They do warn you
>that the transmit frequency is 1 kHz above the indicated frequency while
>in the CW mode.
>
DE N6KB

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