frequency analyzer

[Popr]

I build golf clubs and bought a frequency analyzer to check flex rating from a golf distributor. Problem is it is too small. I need help putting together a counter/tachometer that will calculate a frequency number using sensors that I can put 18 to 24 inches apart.
Popr

 

[Nanren888]

Sorry?
An electronics & signals guy here.
A what?
Got a picture? Or a data sheet or something?
A couple of keywords for google?

 

[Harald Kapp]

A what?

See here.

Problem is it is too small. I need help putting together a counter/tachometer that will calculate a frequency number using sensors that I can put 18 to 24 inches apart.

We need more details. I for one do not understand the need for the sensors to be spaced farther apart. The frequency of the club is independent from the distance between the sensors. If the analyzer is built for measuring golf clubs, it should do so regardless of the distance between sensors.
For comparison: the pitch of a violin will not depend on the size of the microphone used to record the sound.

 

[poor mystic]

Here's a link
https://www.mitchellgolf.com/shaft-frequency-an-absolute-measurement-for-shaft-matching/