Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Read frequency of tuning fork on counter  (Read 2623 times)
KD2E
Member

Posts: 231




Ignore
« on: February 18, 2013, 10:30:50 AM »

Trying to read the frequency of a tuning fork using my counter.
I suspect my dynamic tape recorder microphone just does not have the
output required for the counter to trigger.

So, would you suggest a ceramic or crystal element....or is there a WAY better
method of doing this.....without building a circuit to add to the mix.

Thanks for any suggestions.

....Dave
Logged
KB3HG
Member

Posts: 404




Ignore
« Reply #1 on: February 18, 2013, 11:49:49 AM »

A thought,  record the tuning fork on your pc playback through speakers tap speakers for sampling. Heck even you cell phone might record well enough. I'm really thinking that an electret (Wide 30-15,000Hz frequency response) vs condenser (Wide 50-10,000Hz frequency response) crystal or ceramic would be better. wav or mpeg files

Tom Kb3hg
Logged
KA4POL
Member

Posts: 1903




Ignore
« Reply #2 on: February 18, 2013, 12:23:41 PM »

You can measure very accurate using http://www.qsl.net/dl4yhf/spectra1.html
A laptop microphone is sufficeint. I used it for tuning low frequency generators.
Logged
KD0REQ
Member

Posts: 849




Ignore
« Reply #3 on: February 18, 2013, 01:38:28 PM »

or wind a coil around the tuning fork, hook it to the freq counter, strike the fork and hold it to a magnet.  if there is enough wire, you can get enough voltage to feed the counter's chips.

the reverse was used in the 30s for master clock timing in radio.  General Radio had an oven-mounted tuning fork driven with big-boned triodes that output 115 volts at exactly 60 cycles to power clocks.  the triodes ran magnets that vibrated the fork.

this was before Hammond (the organ guy) slyly made the electric grid stable by giving away his then-signature product, the syncronous-motor clock, to power company executives.  they didn't keep good time until the plant operators started hanging on their controls and keeping the speed constant, and the power execs made it happen so they could keep the pretty clocks on their polished desks.
Logged
KE3WD
Member

Posts: 5694




Ignore
« Reply #4 on: February 18, 2013, 04:05:04 PM »

What counter is involved?  Does it have preselector on it in order to get down into the audio region? 

What is the input spec for the counter?  Input Impedance may be 50 ohms and able to load down ANY mic output.


73
Logged
K0JEG
Member

Posts: 631




Ignore
« Reply #5 on: February 19, 2013, 03:19:01 PM »

or wind a coil around the tuning fork, hook it to the freq counter, strike the fork and hold it to a magnet.  if there is enough wire, you can get enough voltage to feed the counter's chips.

the reverse was used in the 30s for master clock timing in radio.  General Radio had an oven-mounted tuning fork driven with big-boned triodes that output 115 volts at exactly 60 cycles to power clocks.  the triodes ran magnets that vibrated the fork.

Also the basic theory of operation for an Accutron watch. Later adapted by Seiko for the Pulsar quartz watch that is used by nearly everyone today.
Logged
KD2E
Member

Posts: 231




Ignore
« Reply #6 on: February 19, 2013, 03:27:16 PM »

the "motor" theory is cool, but might be mechanically difficult.
Anything touching the tuning fork....even lightly...stops it from
vibrating instantly.
Logged
TANAKASAN
Member

Posts: 933




Ignore
« Reply #7 on: February 20, 2013, 01:04:32 AM »

Interesting problem, I played around with this until I got a reasonable solution:

1) As others have suggested you need to boost the output of your microphone as the output will be too low to trigger the counter. Any audio amp should do.

2) Place the microphone on a hard surface.

3) Strike the tuning fork then place it on top of the microphone.

Tanakasan
Logged
AA4PB
Member

Posts: 12667




Ignore
« Reply #8 on: February 20, 2013, 05:44:39 AM »

....or is there a WAY better method of doing this.....

....Dave

Use your computer sound card with a microphone and one of the free audio spectrum analyzer programs.
Logged
N7EKU
Member

Posts: 42




Ignore
« Reply #9 on: March 13, 2013, 03:47:52 PM »

Way better than all of the above!

Simply use a sound generator program on your pc to play a tone and vary it until it zero beats with the tuning fork.

73,


Mark.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!