[Boatanchors] Crystal Set Progress

[hwhall at compuserve.com]

Yep, you're right. Those dual sliders didn't have tuning caps after all. They did *look* loke they were once high-end to my eyes.
 

 Wayne
WB4OGM

 

-----Original Message-----
From: Al Klase <ark at ar88.net>
To: boatanchors <boatanchors at mailman.qth.net>
Sent: Thu, Apr 23, 2015 11:08 pm
Subject: Re: [Boatanchors] Crystal Set Progress


Wayne,

Name one.

Yes, there were two-slide tuners, but mostly that's what hams
did when 
they couldn't afford variable caps.  So, I submit "high-end" is a

stretch.  Serious radios were more like this WWI Telefunken crystal 
set: 
http://users.erols.com/oldradio/eha13.htm  Picture of that radio 
is at the
bottom of this page: http://www.skywaves.ar88.net/xtal/xtal.htm

Al

Al Klase –
N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

On 4/24/2015 12:54 AM,
hwhall at compuserve.com wrote:
> Some of the high-end old-time crystal sets had
dual sliders on the 
> tuned coil, presumably to let one vary the detector
tap-off as well as 
> the number of turns across the tuning capacitor. Wayne
WB4OGM -----

> Original Message----- From: Al Klase <ark at ar88.net> To:
boatanchors 
> <boatanchors at mailman.qth.net> Sent: Thu, Apr 23, 2015 10:36 pm 
>
Subject: Re: [Boatanchors] Crystal Set Progress Gene, I see two 
> problems with
that approach. Perhaps the biggest is that if the slider 
> touches two adjacent
turns, it results in a shorted turn in the coil 
> that causes a great amount of
loss. Even if you can avoid that problem 
> with a carefully designed slider,
it's still difficult to design a 
> high-performance receiver around a simple
untapped inductor. The 
> difference between a brain-dead design and a good one
is quite 
> striking. You can get a feel for some of the issues and appropriate

> circuit topologies here: 
>
http://www.skywaves.ar88.net/xtalset102/xtalset102.htm Sorry, you got 
> me on
one of my favorite subjects. Al Al Klase – N3FRQ Jersey City, NJ 
>
http://www.skywaves.ar88.net/

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