home-made Q-meter

Place a 50ohm resistor in series with its output, then into the 0.1ohm

-> done :-)

Use news.individual.de, 10 Euros per year and they do not allow nym-shifting.

I preferred Danish Butter Cookie cans for such jobs. Tastes better :-)

I have a Boonton 260A, I don't use it much though. No, I don't want to sell it :-) (Premptive reply)

I usually tried to couple energy into the inductor by radiation and isolated the scope probe capacitance with a high value resistor. MikeK

On a sunny day (Fri, 10 Sep 2010 08:07:40 -0700 (PDT)) it happened Tim Williams wrote in :

Exactly what I thought, and that site says uH! I just tried it with my meter and get 200 nH! Somebody shoud alert that guy at that site... :-)

I suppose.

We had a military preferred unit that was used when ever a shipment of caps were sent to a military customer...

This unit occupied the size of two average desk.. On the right was where the operator sat and operate the mechanical dial capacitor modules that had a test jig fixture attach to them.. They slid into a sloping panel where each one had an oscillator, ~ 1MHz via an acorn tube.

On the left was basically a short wave receiver, set around 1 MHz with it's BFO circuit in it.. This unit had an output of it's generated frequency along with a buffered output of the signal coming from the mechanical test jig oscillators. These outputs were used on a X,Y input of a scope for absolute tuning down to 0 hz offset. The receiver on the left also had audible sound for the operator to listen to. Kind of you reminds me back in the days of the old black & White mad scientist movies :)

The military considered this to be the ultimate for precision testing .. I guess Motorola also thought that too, because they once purchased a series of various values of dip mica caps, each tested on this equipment in the lab and properly marked so they could use these as test specimens when they were designing a LCR bridge themselves. What was strange is, even though they had a range of caps from us to work with, we found that none of their units could properly generate the same results across the board. So, there they sat on other tables in the lab just for looks and really never used for precision testing.

The employee's call this machine the Gray Monster.

Jamie.

It sounds like it should be called Obsolete Shit.

Thanks for reminding me about Terman. I have his 1932 edition of Radio Engineering, and it has some useful notes about coil Q. Of course, all the stuff then was BIG and low frequency, and powdered iron wasn't very good past audio frequencies.

John

These electronic enclosures are excellent for storing small parts and packaging shielded circuits.

ftp://jjlarkin.lmi.net/Cans.JPG

I use a lot of them.

John

Nice! We can't get those here.

Order online!

John

Pretty modest prices, that's nice. But I better not because then I'll grow. Sideways :-(

Here's a scan of the Theory of operation page for the Boonton 260A.

Please explain "handle" and "complain."

Yup, that's what I'm doing.

John

This guy has the whole manual, 38 megabytes of same. The 260A uses a

John

...Tabasco sauce extra..

The miltary has a tendency to overgeneralize scope of competence. Some PHd might be a whiz-bang genius on gyro electronics, but then insists on certain parts measurements be done their way (and often floogging up some side business).

Its use in 10.7 MHz FM IF cans in the tube days (50+ years ago) was not uncommon.

Interesting, i had learned of eddy current as a core loss mode ('bout