On 1/3/09 12:33 AM, "Christos" <sv1...@otenet.gr> wrote:
> It is not actually a carrier but LO leakage from the commutator ic FST3253 and
> there is no adjustment you can make to null it on this implementation.
> I use sdr1k with the 100w PA and I have measured this leakage to be -20dbm @
> 160m (70db below 100w)and 0dbm @ 10 m (50 db below 100w but only 30 db below
> 1w).
> While you transmit on ssb it is on your vfo frequency and at am/fm it is on
> vfo - if.
> You can also trace it during reception but with much lower level.
>
> 73 Christos
>
One might be able to null it if you have an audio interface with response
down to DC? Or is it just leakage around the part, from the DDS output to
the antenna output. (that is, if you were to disable the FST3253 so that it
never turned on any of the switches, would you still get the feedthrough?)
Is the F5K or the WonderRadio better or worse? (different PCB layout,
different parts)
Jim, W6RMK
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