Author Topic: Calibration club standard inductor and capacitor?  (Read 546 times)

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Offline rhb

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Calibration club standard inductor and capacitor?
« on: March 23, 2018, 01:25:50 am »
I have a rather large pile of WWII antenna tuning units.  These were built of the finest materials of the day.  Steatite insulators and silver plated wire and switches. I'd guess they are rated to several hundred volts and watts.

Would it be useful to have some traveling references?  What I have in mind is mounting them in an enclosure and pulling a fairly hard (e.g.  a few microns) vacuum.   Then installing that in a larger enclosure with insulation and a temperature control circuit.  The outer enclosures would be made from the tuning unit front panel and the case.  They're roughly standard rack size, but I've never measured on.  It's all aluminum, so lightweight.

I don't propose to trim them to value.  Rather the idea is to have a number of precisely measured values made from very stable materials.  Have a USB interface that would allow reading temperature and frequency correction factors and verifying vacuum integrity.
 

Offline Conrad Hoffman

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Re: Calibration club standard inductor and capacitor?
« Reply #1 on: March 23, 2018, 02:42:26 am »
As the box gets larger, shipping costs get out of hand. There were various things I wanted to include last time, but couldn't. Maybe better to have some standards without stabilization and just record temperature and establish a calibration curve?
 

Offline TiN

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Re: Calibration club standard inductor and capacitor?
« Reply #2 on: March 23, 2018, 03:48:04 am »
I had some data samples received recently from capacitance bridge, which I'd like to keep unnamed for time being, with two standard capacitors as DUT: 10 and 1000 paff.
Test frequency : 1000 Hz.  :) I'm impressed with resolution. Vertical scale on the most left - ppm of the reading.   :box:
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Offline cellularmitosis

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Re: Calibration club standard inductor and capacitor?
« Reply #3 on: March 23, 2018, 04:29:54 am »
13 oz. is the magic number for being able to use US Postal Service First Class Package service, which is usually the cheapest shipping option.  Beyond that it becomes a hunt between UPS, Fedex and the flat-rate Priority Mail options from USPS.

One approach you could take is to attempt to keep a few heavier, ultra-stable known-good references at home, and then ship around a lighter transfer standard, which can be calibrated / adjusted to your known-good references at home after each leg of the trip.  This is what I'm going to attempt to do with resistance standards, anyway (oil-immersed at home, copper-wire tempco resistor compensated for the traveling references).
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Offline rhb

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Re: Calibration club standard inductor and capacitor?
« Reply #4 on: March 25, 2018, 12:03:30 pm »
@TiN  I see that the key shows environmental data which are not plotted.  Can you post the temperature, humidity and pressure data?
 

Offline TiN

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Re: Calibration club standard inductor and capacitor?
« Reply #5 on: March 25, 2018, 03:14:14 pm »
Not at the moment, that data was not logged for these initial measurements, sorry.
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