GPSDO for Position Location, Time and Frequency Standard and updates since May

August 06, 2019

Found this interesting RTK GPS system module that is accurate down to 1cm, yeah, 1cm is what is claimed. This video is the source: https://www.youtube.com/watch?v=_a1ixhYJe60
Figured I'd share. https://www.sparkfun.com/products/15136

Reference comparison oscillators:
https://en.wikipedia.org/wiki/Crystal_oven#Comparison_with_other_frequency_standards

Updates Since May:

Hackaday: rtl-sdr-seven-years-later article with comments detailing applications

Hackaday: tuning-into-atomic-radio-quantum-technique-unlocks-laser-based-radio-reception/

Neat system... though I'd like to work on a cost effective DIY wideband laser interferometer to more easily perform a mHz to ̶E̶̶H̶̶z̶̶ PHz spectrum analysis. Still... this system seems interesting.

The below post corrupted me when I posted a comment, along with watching a video by The thought emporium to make a similar interferometer about the same time and a video by Physics Girl a few weeks later about how the LIGO system operates... got me thinking how not complicated a decent wideband laser interferometer can be made either using say a webcam as a detector or maybe a Cartesian coordinate system arranged laser frequency sensor detector since the image processing of the laser pattern isn't really required. Horizontal and Vertical positioned sensors should provide the information to at least determine the axis plane of the signal and I'm thinking that will correlate to polarity depending on the signal source.
https://www.instructables.com/.../Make-Your-Own-Really.../

Software references:

Theremino:
https://www.youtube.com/watch?v=32JO1ikgzXU
https://www.youtube.com/watch?v=6s47DhT2D7I

Three tasks to perform to bring user privacy of Ubuntu/Lubuntu 18.04 up to par with Mint:

1. ubuntu-report -f send no

2. sudo apt remove popularity-contest

3. Click the system status icons at the top right corner of the Ubuntu desktop and click the “Settings” icon in the popup. Select “Privacy” in the Settings window that appears, and then click the “Problem Reporting” entry. Set “Automatic Problem Reporting” to “Off” and close the window.

Lock-In Amplifier with Differential Pre-Amp:

I was just offered a Princeton Applied Research 124a lock-in amplifier with the model 116 differential pre-amp. I think I can modify and improve in other ways to make more modern. I went ahead and accepted the random offer. Hhhmmm... seems like a good price and will definitely need some restoring... though maybe not. Was also offered free shipping with a new invoice for the PAR124a since I mentioned one just sold for $200.

Wow... didn't expect, though is a nice independence day system that is a Made in the USA rescue to add to the count of another saved system.

I'm thinking with this I might be able to hear the SAQ Grimeton transmission now in Michigan and not only potentially on the east coast only.

Here are some references:

http://67.225.133.110/…/PAR_124A_Lock-In_Amplifier-Instruct…

http://groups.physics.umn.edu/…/man…/measurement/PAR124A.pdf

https://www.thinksrs.com/products/sr2124124.html

This will be an interesting project to learn about the history of Lock-In Amplifiers as well as most likely a great upgrade project. Figure ~$25 for the AD630 or double that for a module... was and still am thinking upgraded components (if equal to and better in specs) are the better route to go. Plus another Made in the USA rescue with components/parts that can be repaired, restored and upgraded.

James Analytic Definitely will be nice to have a GPIB or better output for this system (not sure if can be controlled with yet stock). I'm almost thinking a new display also for a more sensitive readout. Have to read the schematics to see how the output is ran... since the display technically has the values I'd want to feed out to process if even on an MCU/SBC... for logging also.