General Radio Frequency Standard

I recently picked up a rack of old gear from the garage of a local silent key. They were in rough shape with leaky caps, rust, and corrosion, but deep inside a crystal oven I found this.

IMG_20160717_110659

This was part of an FAA frequency standard. It was mounted in an aluminum enclosure with about 1/4″ walls. This was surrounded by about a half inch of styrofoam and then a slightly thinner aluminum enclosure. That outer enclosure had three resistors on each side used to heat it and that was enclosed (with some air space) in a wooden box.

To align this, there was a WWV receiver and various other gear. I’d only be guessing on the accuracy, but I recently ordered a GPSDO (GPS disciplined oscillator) that is better than 1 part-per-billion in accuracy. I don’t doubt that is significantly better than this could offer even when it was freshly calibrated.

There is a slight chip in the upper right hand corner of the quartz bar. It is held in place by what looks like fishing line and a series of springs.the leads aren’t visible–they are whisker thin and soldered to the gold plating on the bottom of the quartz bar.

I was going to build a 100 kHz marker generator with this and still might on day, but for now I’ll probably stick with the 10 MHz GPSDO around the home lab.

73 de
Jim W4JBM

“With a soldering iron in one hand, a schematic in the other, and a puzzled look on his face.”

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s