Questions About Construction Of The Australian Mystery Crystal Set

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I've been looking at a number of simple crystal radio designs, and
I've found the Australian mystery crystal set, and am interested in
building that, mainly because it's an Australian design, and I've
heard it it's a pretty good performer. I only have 2 questions- can I
substitute the detector for a 1N34? and what is  double silk covered
wire and do I really have use that?  What's wrong with regular coil
wire? I can only find 23 SWG, 25 SWG, and 33 SWG where I need 24 SWG,
30 SWG.

Thanks

Dave

Re: Questions About Construction Of The Australian Mystery Crystal Set
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Forgot to give the schematic
http://www.clarion.org.au/crystalset/mystery.html

Re: Questions About Construction Of The Australian Mystery Crystal Set

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Substitutes will work fine. All the other stuff is to make it look like
a "period piece." Go to a rock shop and get some galena for the detector
if you want to go retro.

Steve.
--
Steven D. Swift, novatech@eskimo.com, http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC.      P.O. Box 55997
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Re: Questions About Construction Of The Australian Mystery Crystal Set



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It's wire insulated with silk.

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Not unless you want it to be 'period authentic'.

Graham


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Not really, I'm building it on a metal chassis (coil mounted above,
vertically) and don't really care about vintage looks. I can't seem to
find wire of the right diameter, though, that's the only part I've yet
to find.

Re: Questions About Construction Of The Australian Mystery Crystal Set
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A metal chassis can influence performance very much,
because metal in front of a coil acts as a shorted
winding.
I advise to test things without a chassis, on a non-metal
table surface, and when it performs as intended,
try it in your metal housing.
I would choose a wooden or plastic box however.

Re: Questions About Construction Of The Australian Mystery Crystal Set
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I've been thinking about that, and decided to go with my original
intention; mount everything on a piece of pine board, '20's style.

Re: Questions About Construction Of The Australian Mystery Crystal Set
On 3/9/08 5:03 PM, in article
bf96e056-ebfc-4488-b9d1-20dd29d380cf@h11g2000prf.googlegroups.com, "Dave.H"

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That's a great looking radio.

Use 23 or 25 or whatever is handy.  The significant difference between
cotton covered and enamel covered wires is that cotton spaces the wires a
little farther apart than will the enamel, and it will take slightly more
cotton covered wire to lay on the same number of turns as the enamel wire.
Bottom line is, the two coils would have slightly difference inductive
reactance.  The turns count is probably a swag anyhow, and it's the reason
most xtal sets using wound coils, put on lots of turns with taps so the
range of tuning can be easily changed (hint, hint).

I don't know what a really good replacement for the 1N34 would be.  I'd look
for a Hot Carrier diode if nobody comes up with a part number.  From an
occasionally defective memory, I think the 1N82 may be one.



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"Donald Duck  Bowey"

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**  Try reading the damn question  -  fuckwit.



.......   Phil



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On 3/9/08 6:04 PM, in article 63jfp9F256cl0U1@mid.individual.net, "Phil

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Sorry grampa.  I'll try to do better next time.

If you keep using those naughty words I'm going to tell on you.

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Re: Questions About Construction Of The Australian Mystery Crystal Set

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http://www.rwonline.com/pages/s.0055/t.5708.html
   Read that, it's interesing., don't know if it'll
help you how ever. I'm guessing that if you used enamel
wire you would be fine for what you're doing.
--
http://webpages.charter.net/jamie_5 "


Re: Questions About Construction Of The Australian Mystery Crystal Set
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You can use regular coil wire of whatever size you
can get that is close, and the 1N34 is fine as the
detector.

Ed

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You might do rather well with a zero bias schottky diode.

Failing that, any germamium point-contact type (like the 1N34) would be a
decent sub.

Graham


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I'll go with the 1N34.  I'm also going to install a 1S5 tube as a
second detector, switchable between the two, with a 'D' cell powering
the filament.

Re: Questions About Construction Of The Australian Mystery Crystal Set

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  Hi Dave,
  I almost feel bad giving you this URL, it is so full of useful information
that it may be a while before you have time to get anything done. See
section 1. Out of the 29 atricles, I think 5 or 6 are about how to improve
the diode/detector operation. Oh, and see #19, Ben discusses the 1932
"Mystery Crystal Radio"
http://www.bentongue.com/xtalset/xtalset.html
                       Have fun,   Mike
*and what's this stuff about a D cell on a crystal radio :-)



Re: Questions About Construction Of The Australian Mystery Crystal Set

*and what's this stuff about a D cell on a crystal radio :-)

I got the idea from one of Dave Schmarder's radios, #26

http://www.schmarder.com/radios/crystal/26.htm

Re: Questions About Construction Of The Australian Mystery Crystal Set

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  Hi Dave,
   My point was, the purists would shudder at the thought of an external
power source on a crystal radio. Now if you extract the power from a strong
local and use that to amplify a weak signal then your doing good work.
               Mike



Re: Questions About Construction Of The Australian Mystery Crystal Set
On 3/11/08 5:15 AM, in article 91512$47d674c2$18d6b40c$1163@KNOLOGY.NET,

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The tube isn't being used as an amplifier, it's diode is used as a
switchable option to a SS diode.  The battery is for it's filament.



Re: Questions About Construction Of The Australian MysteryCrystal Set

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Ok then, the purists would shudder at the thought of an external
 power source on a crystal radio. Now if you extract the power from a strong
local and use that to bias your diode then your doing good work.
  Gees Don, your acting like Phil but without the name calling :-)
                                                    Mike


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Re: Questions About Construction Of The Australian MysteryCrystal Set
On 3/11/08 3:51 PM, in article 47475$47d70c71$45013908$18402@KNOLOGY.NET,

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Geez Mike, why didn't you take time to see what the OP was doing?

If you wish to really be a purist you should insist one should use a coherer
for the detector, or a chunk of galena and a cats-whisker.

I think it's a bit cool to have two different detectors and be able to
switch between them, like in the good old days.



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