2014 14:01
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] optically excite a quartz crystal?
I'm puzzling over this statement. The FT-243's I have seen have a spring
that squishes the quartz blank between the electrodes. They aren't plated
onto the quartz
On Mon, 21 Apr 2014 17:12:54 +1200
Bruce Griffiths bruce.griffi...@xtra.co.nz wrote:
Optical excitation of quartz resonators: Electronics Letters
http://digital-library.theiet.org/content/journals/el, Volume 18,
Issue 9 http://digital-library.theiet.org/content/journals/el/18/9, 29
April
On 04/21/2014 11:40 AM, Attila Kinali wrote:
On Mon, 21 Apr 2014 17:12:54 +1200
Bruce Griffiths bruce.griffi...@xtra.co.nz wrote:
Optical excitation of quartz resonators: Electronics Letters
http://digital-library.theiet.org/content/journals/el, Volume 18,
Issue 9
I'm puzzling over this statement. The FT-243's I have seen have a spring
that squishes the quartz blank between the electrodes. They aren't plated
onto the quartz, but they are still in intimate mechanical and electrical
contact.
-Chuck Harris
Bob Camp wrote:
Hi
The WWII era FT-243 is one
and frequency measurement
Subject: Re: [time-nuts] optically excite a quartz crystal?
Hi
The WWII era FT-243 is one example of a crystal that has the active portion
of the electrodes separated from the resonator by an air gap. There are lots
of similar holders from that era that do pretty much the same thing
Hi
If you look closely at most of them, the plates are not flat. They are higher
on the edges than in the center. There’s a gap in the middle. If you don’t have
the gap, the blank is constrained by the big heavy plate. That damps the
resonance and lowers the Q.
Bob
On Apr 21, 2014, at 9:00
On Mon, 21 Apr 2014 14:54:12 +0200
Magnus Danielson mag...@rubidium.dyndns.org wrote:
They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on
various quartz cuts (X+5°, DT, AT) and could measure oscillations
of the quartz using metal electrodes.
The mechanism of exitation was
Subject: Re: [time-nuts] optically excite a quartz crystal?
Hi
If you look closely at most of them, the plates are not flat. They are
higher on the edges than in the center. There's a gap in the middle. If you
don't have the gap, the blank is constrained by the big heavy plate. That
damps the resonance
and frequency measurement
Subject: Re: [time-nuts] optically excite a quartz crystal?
Hi
If you look closely at most of them, the plates are not flat. They are
higher on the edges than in the center. There's a gap in the middle. If you
don't have the gap, the blank is constrained by the big heavy
On 04/21/2014 03:18 PM, Attila Kinali wrote:
On Mon, 21 Apr 2014 14:54:12 +0200
Magnus Danielson mag...@rubidium.dyndns.org wrote:
They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on
various quartz cuts (X+5°, DT, AT) and could measure oscillations
of the quartz using metal
Hi
If you are going to thermally excite the resonator, and measure the resonance
optically, there’s no reason at all to use quartz. There are other materials
with much higher acoustic Q than quartz.
Bob
On Apr 21, 2014, at 9:47 AM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
On
No. There is just a little rectangular quartz wafer. No plating.
In fact, post WWII, when many ham transmitters were 'rock bound' (ie:
crystal conteolled) it was common pratice to regrind mil surplus rystals
to move them into the ham banda.
Apparently, some were also etched using a cleanser
Hi
Early in the WWII era, quartz blanks were not commonly etched after begin
ground / polished to frequency. This left debris on the surface of the blank.
The net result was that the resonators failed after a period of time in the
field, especially under damp conditions. The problem got so bad
In message a5032606-d7d7-4231-b1bd-434670274...@rtty.us, Bob Camp writes:
Early in the WWII era, quartz blanks were not commonly etched after
begin ground / polished to frequency. This left debris on the surface
of the blank. The net result was that the resonators failed after
a period of time in
Who said they were plated?
-Chuck Harris
J. Forster wrote:
No. There is just a little rectangular quartz wafer. No plating.
In fact, post WWII, when many ham transmitters were 'rock bound' (ie:
crystal conteolled) it was common pratice to regrind mil surplus rystals
to move them into the ham
The etching referred to was by post-war hams,
-John
===
Hi
Early in the WWII era, quartz blanks were not commonly etched after begin
ground / polished to frequency. This left debris on the surface of the
blank. The net result was that the resonators failed after a period of
Hi
As with all “good stories” there are many versions told by many people. I’ve
heard far to many mutually contradictory versions to have any real idea what’s
true. You are correct that etching was a known process in the 1930’s and that
it had been used by various people at various times.
Hi
Well I can name at least one post war ham (me at age 14) who did not understand
the need for etch after grinding…
Bob
On Apr 21, 2014, at 11:21 AM, J. Forster j...@quikus.com wrote:
The etching referred to was by post-war hams,
-John
===
Hi
Early in the WWII
Bob,
We all start somewhere.
Today one buys aged equipment with fancy synthesis so that fooling
around with crystals, etching or graphiting them won't be necessary.
Hell, someone taking the time to calibrate their transceiver is rare
these days.
Cheers,
Magnus
When this question was first posed, AOM's first jumped to my mind. An AOM
(sometimes AOD) is an Acousto-Optic Modulator that works by setting up an
acoustic wave in a crystal. When a laser is directed through (or reflected by)
an AOM, it is deflected.
One way to think about this is the
In message aabkxjbn5aj3w...@smtpout04.dca.untd.com, cdel...@juno.com writes:
After reading about how the BVA oscillators avoid the problems of on
crystal electrodes I was wondering if anyone has tried to optically
excite a quartz crystal in an oscillator?
I can see optical detection, but I have a
Hi Corby,
On 04/20/2014 07:35 PM, cdel...@juno.com wrote:
After reading about how the BVA oscillators avoid the problems of on
crystal electrodes I was wondering if anyone has tried to optically
excite a quartz crystal in an oscillator?
(Use a modulated laser to drive the bare crystal, and a
If laser excitation won't work, how about sound, as an opera singer
breaking a glass?
Use feedback control to bring the driven crystal to resonance with the
free crystal. Might need to go down to 100 KHz to make this practical.
Speaking of practical, how would you levitate the free crystal?
On Sun, 20 Apr 2014 10:35:08 -0700
cdel...@juno.com wrote:
After reading about how the BVA oscillators avoid the problems of on
crystal electrodes I was wondering if anyone has tried to optically
excite a quartz crystal in an oscillator?
(Use a modulated laser to drive the bare crystal, and
Quartz is piezoelectric, so it deforms due to electrostatic fields and
vice versa. This is exactly what is being used in quartz oscillators.
For the BVA, the resonator is hanging in bridges of the same quartz
crystal it is being cut out from, and the orientation of the blank is
such that these
to the fun with wood group send a blank email to
funwithwood-subscr...@yahoogroups.com
- Original Message -
From: Attila Kinali att...@kinali.ch
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Sunday, April 20, 2014 2:50 PM
Subject: Re: [time-nuts] optically
@febo.com
Sent: Sunday, April 20, 2014 2:50 PM
Subject: Re: [time-nuts] optically excite a quartz crystal?
On Sun, 20 Apr 2014 10:35:08 -0700
cdel...@juno.com wrote:
After reading about how the BVA oscillators avoid the problems of on
crystal electrodes I was wondering if anyone has tried
: Sunday, April 20, 2014 2:50 PM
Subject: Re: [time-nuts] optically excite a quartz crystal?
On Sun, 20 Apr 2014 10:35:08 -0700
cdel...@juno.com wrote:
After reading about how the BVA oscillators avoid the problems of on
crystal electrodes I was wondering if anyone has tried to optically
excite
Optical excitation of quartz resonators: Electronics Letters
http://digital-library.theiet.org/content/journals/el, Volume 18,
Issue 9 http://digital-library.theiet.org/content/journals/el/18/9, 29
April 1982, p. 381 – 382
Bruce
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