Here we go again....;-)
SM5KI:
> >Before talking down the G2DAF circuit I may ask has anybody measured the
> >distorsion in it?
AG6K:
> Yes. In two units the total IMD was c. -22db below peak envelope power.
> One DAF amplifier used 813s. The other used 4CX250Bs.
SM3BDZ:
And from what I understand, measured by listening for the bandwidth, on air.
That will give you an idea of the quality ofcourse, but I would not consider
that methode to be acurate when it comes to precise IMD figures. You cant be
sure if you observe bad IMD in your own RX? The other guys TX? Or both !? On
the other hand, I´ve heard some amps with 4CX250 over the years. They all had a
very ugly distortion - and regulated screen...;-) I should not blame the tubes,
my guess is that most hams can not handle those creatures....
Myself, I also did some measurements on G2DAF circuit using HP Spectrum
analyzer/plotter and voice sample as signal source. I like what I see!
SM5KI:
> > Where and when was this published?
AG6K:
> It was published live on the 40m band whenever people were being
> interfered with by a DAF amplifier. . I was the publisher.
SM3BDZ:
I ve published the results as email and imagefiles to interested people, among
them AG6K.
With some exception, I ve also received positive response from these guys.
The exception is AG6K....;-) You did´nt say a word Rich....
73´s and seasons greetings to you all!
Lars /SM3BDZ
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