At the Crawley LF roundtable a few weeks ago somebody asked me if I'd
measured the stability of an FT-817, but I hadn't.
Now I have. After running it for 24 hrs I set it to track a harmonic of my
5 MHz Rb standard at 145 MHz. Over the
following 24 hrs it very slowly drifted about as the shack temperature
changed but never exceeded 20 Hz deviation.
This on its standard osc, NOT the hi-stab TCXO option. This is quite
remarkably good - far better than my Icom 706
which has ICOM's "hi-stab" option and constantly jitters 30-50 Hz at the
same freq. mainly due to its internal fan.
It's not far off my IC-821 which also has the hi-stab option.
I've written to ICOM recommending they should provide a facility in all
their top-end stuff for inputting a sub-standard
5 or 10 MHz as frequency reference. No reply yet!
Incidentally I think the idea of buying a cheap synthesized HF sig gen as
the basis of an LF rig an excellent one. Nobody wants
sig gens that don't go to 1 GHz these days so they're quite cheap and if
they have a first-order OCXO as reference they'll
do very nicely. Stewarts of Reading have a vast selection and are very
helpful.
Walter G3JKV.
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