Low Cost Lab Frequency Reference

The internals of a home built 10 MHz frequency reference.

[Mark] wanted an accurate frequency reference for his electronics lab. He specified some requirements for the project, including portability, ability to work inside a building, and low cost. That ruled out GPS, cesium standard clocks, rubidium standard clocks, and left him looking for a low cost Oven Controlled Crystal Oscillator (OCXO).

The Low Cost 10 MHz Frequency Reference is based around a Morion OCXO. These Russian oscillators are available from eBay second hand at about $40 a pop. With a stability well within the requirements, [Mark] order a few.

The next step was to stick all the components in a box. The two OCXOs in the box need about 3 amps to heat up, which is provided by a 12 V PSU. For portability, a sealed lead acid battery was added. The front panel shows the supply voltages, switches between mains and battery supplies, and provides connectivity to the OCXOs.

Since OCXOs work by heating a crystal to a specific temperature, they can use quite a bit of power in the heating element. To increase battery life, a neoprene foam insulator was wrapped around the OCXOs.

For less than $100, this portable tool will aid in calibrating equipment or creating very accurate clocks.

Neosporin…the Retrobright for bench equipment?

polishing-knobs

[linux-works] picked up an old power supply from eBay, and as it was built back in the 60’s or 70’s, it was in need of a little TLC. One thing that immediately caught his eye was the condition of the knobs, dials, and banana plug receptacles – they were dull and faded, showing off 40+ years of heavy usage.

He started off by simply removing the knobs from the power supply, giving them a thorough cleaning with soapy water before leaving them to air dry. They didn’t look any better afterward, so he decided to take a different approach and apply some triple antibiotic ointment to the knobs. As it turns out, letting the ointment sit for a few minutes then wiping the knobs with a soft cloth really made them shine, as you can see in the image above. [linux-works] attributes the effect to the white petrolatum base of the product rather than the antibiotics, likely making a wide array of products equally suitable for the job.

We know how well Retr0bright has worked for the vintage computer folks, so we’ll be interested to see how long the effects of the triple antibiotic treatment last. It certainly can’t hurt those readers who spend their time perusing flea markets in search of classic electronic equipment.

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