If you are a member of the ARRL,
you have access to all the old QST's
in pdf format on the League website.
The search engine works too !!
Also, you can get the entire run of
Ham Radio Magazine in pdf format
for free on the web.
That magazine was a Home-Brewers dream.
73, Dick, W1KSZ
On Wed, Jan 4, 2017 at 6:00 PM, Rob Atkinson <ranchorobbo@gmail.com> wrote:
> >
> > I recently bought a 1955 ARRL Handbook and a Bill Orr book from the
> 1960s so
> > that I could have references that cover tube theory and practice.
> Nothing
> > recent covers it.
> >
>
> You need a lot more than that. Go to hamfests and look for and start
> buying up QSTs from before around 1955, ditto for handbooks, don't
> overlook tube manuals, the RCA Redbook, IIT Engineers Handbook,
> anything by Terman, and Sterling, West Coat radio handbooks dating
> back to the 1930s, the entire run of Electric Radio, issues of Radio
> magazine before it moved to the east to become CQ, the LaPort's
> antenna book, metal working shop textbooks, that should keep you busy
> for a while.
>
>
> > Let's face it: SSB transmitters control the output power by means of
> ALC. It's the best method found to date, as far as I know, at least for
> voice transmission.
>
> It is a cheap and poor way of controlling voice peaks. In the typical
> solid state transceiver, the output is sampled and converted to a
> control voltage that is fed back to a VCA in an early low level stage
> of amplification, to automatically reduce the gain of the low level
> driver. The obvious problem with this scheme is that by the time VCA
> acts, the horse is through the gate and out on the loose, i.e. that
> big RF peak is gone. If the VCA has slow recovery it may catch other
> RF power peaks and limit them, but it is really a poor scheme and
> you'll never find it in any professional equipment as far as I know.
> Far better is to employ a fast broadcast peak limiter at baseband but
> that costs $$$ and 99% of hams won't want to spend it. A manufacturer
> could build such a circuit into a rig at a significant additional cost
> but now you've added something that most hams are not trained to
> employ, won't understand or appreciate. The ALC method is far cheaper
> but inferior.
>
> 73 & happy new year
>
> Rob
> K5UJ
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>
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