Re: What's difficult in DIY audio?

"John Byrns" <byrnsj@xxxxxxxxxxxxx> wrote in message
news:byrnsj-D9C062.08563130052007@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <esmdnfnEPoXU5MDbnZ2dnUVZ_hOdnZ2d@xxxxxxxxxxx>,
"Arny Krueger" <arnyk@xxxxxxxxxx> wrote:

"Peter Wieck" <pfjw@xxxxxxx> wrote in message
news:1180491734.775980.124750@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
On May 29, 4:28 pm, robert casey <wa2...@xxxxxxxxxxxxx>
wrote:
For some real fun, build a high performance FM tube
tuner from scratch. Getting 100MHz circuits to behave
is another ballgame.

There is a crystal FM tuner out there. I wonder if it is
powerful enough to drive a multiplex adaptor...

http://solomonsmusic.net/FM_CrystalRadio.html

I have to try that some time.

It needs a really strong signal to work at all.

It produces audio based on slope detection, which fails
to exploit FM's resistance to interference.

It's not really because of the slope detection that it
fails to exploit FM's resistance to interference, after
all the traditional discriminator circuit used in tube FM
radios is little more than a push-pull slope detector and
doesn't provide resistance to interference at sideband
frequencies.

I'm under the impression that this article describes accepted practice for
FM detection in common tubed FM radios.

http://www.tpub.com/neets/book12/51d.htm

"The ratio detector is not affected by amplitude variations on the fm wave."

The real reason it fails to exploit FM's
resistance to interference is because it lacks a limiter
circuit.

That, too.

Slope detectors work just fine interference
wise when proceeded by a good limiter.

That, too.



.

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