How Much did the OCXO Drift Since the Last Calibration?

Рет қаралды 5,542

Күн бұрын

In this video I did a quick check on whether the OCXO frequency in my HP5350B had drifted since I last calibrated against a Symmetricom 8040 Rubidium standard. Also I finally got a chance to calibrate the OCXO in my Racal Dana 1992 frequency counter. Links to my the teardowns I mentioned in the video are listed below:
www.kerrywong.com/2014/06/29/h...
www.kerrywong.com/2014/07/01/h...
www.kerrywong.com/2017/01/30/h...
www.kerrywong.com/2017/02/12/t...
www.kerrywong.com/2017/03/04/d...

Пікірлер: 25

@TheDefpom 6 жыл бұрын

If you have issues with the 1992 buttons failing check out my video on replacing them, I have a link in its description to where I got the switches from.

@KerryWongBlog 6 жыл бұрын

Thanks! I will keep that in mind.

@ovi_4 4 жыл бұрын

Great Info thank you, sir.

@Chriva 6 жыл бұрын

Whoho! Another video from Kerry :D

@KerryWongBlog 6 жыл бұрын

:D Not sure if you want to see more or less... LOL

@johnwoods8309 6 жыл бұрын

Thanks for the Video. You may obtain better accuracy by feeding the counter's 10 Mhz oscillator output into channel 1 of an oscilloscope, with the output of the rubidium standard fed into channel two. Use the *fine* adjustment to null any drift between the two traces.

@henrykendall6294 2 жыл бұрын

I know im asking the wrong place but does anyone know of a way to get back into an Instagram account? I was stupid forgot my password. I love any tips you can give me.

@kristopherryland837 2 жыл бұрын

@Henry Kendall Instablaster ;)

@henrykendall6294 2 жыл бұрын

@Kristopher Ryland thanks so much for your reply. I found the site on google and Im trying it out now. I see it takes quite some time so I will get back to you later when my account password hopefully is recovered.

@henrykendall6294 2 жыл бұрын

@Kristopher Ryland it did the trick and I now got access to my account again. Im so happy! Thank you so much you really help me out !

@kristopherryland837 2 жыл бұрын

@Henry Kendall No problem =)

@darrenolafson5266 6 жыл бұрын

I recently bought an EIP 545A from Ebay that was last calibrated 15 years ago. I compared it to a GPSDO and it was about 1Hz out. Not too bad.

@KerryWongBlog 6 жыл бұрын

Yeah, for hobby use, even 10Hz is more accurate than needed. And crystals stabilize over the years so in theory, older equipment probably drift far less than newer ones.

@SoddingaboutSi 5 жыл бұрын

Hi Kerry. On your Racal counter, if you move up to max resolution and hold the up arrow for 2 seconds you will get a further increase in resolution!

@KerryWongBlog 5 жыл бұрын

Aha... thanks for the tips!

@OneBiOzZ 6 жыл бұрын

under that other screw is the fine adjustment knob to get rid of the 0.03hz offset

@KerryWongBlog 6 жыл бұрын

Yeah, I didn't bother with that as the OCXO on the Racal Dana counter isn't that accurate to begin with. The last digit drifts up and down when the oven tries to maintain its temperature...

@OneBiOzZ 6 жыл бұрын

Kerry Wong ah okay, yeah no point adjusting away a digit that keeps drifting

@ciano5475 6 жыл бұрын

Andreas Hettler: Exactly :D

@Burkhardj 6 жыл бұрын

Hey I am close to a time-nut with 2 HP 53131A US Options, 2 Racal Dana US Options too and one old Voltcraft with US Option also. U really need to warm up the US Option OCXOs for 3 days and more. The Rubidium needs more than a week to be stable. I have a the simple chinese FE- 5680A, an unknown symetricon and a few GPS nomal. 1rst rule, never shut down the devices. Thats why most of the devices has no "real" power switch, just a stand by. But what I've seen, you calibrated your Racal Dana with the coars screw only. There's a Fine tune trimmer under the 2nd Screw. With your Rubidium it is easy to calibrate your Racal Dana up to zero. Your Racal Dana has not the resulution to overbid the internal OCXO. Most cheap OCXO or $50 Morion Double Oven CXOs has more accuracy than your Racal Dana can count.

@KerryWongBlog 6 жыл бұрын

I didn't bother with the fine adjustment. As you mentioned, the internal OCXO has a heatup and cool down cycle when powered up, and during that cycle the clock would drift around 5 to 8mHz so adjusting the last digit to "0" is not going to make measurement more accurate due to the uncertainty on the last digit. Yes, these time references are not meant to be shutdown ever.

@KerryWongBlog 6 жыл бұрын

I'll definitely do that. Thanks for the suggestion.

@Mtaalas 6 жыл бұрын

Ummm... adjusting it isn't calibration... calibration is way different from simple checking against a reference.

@OneBiOzZ 6 жыл бұрын

Adjusting a counter to a reference is in fact a form of calibration, you can calibrate other aspects such as gate threshold and other measurements to do a total calibration procedure but a simple frequency calibration is more than good enough for its intended use

@johnbigbooty 6 жыл бұрын

If you are using a Rubidium oscillator like he has as a reference he can. The same goes for GPSDO. Many RF signal generators, frequency counters, and test equipment have an option for 10.0 MHz in and that gives us two wonderful options to calibrate other equipment correctly.