How to test FE-5650A rubidium time standard against Leo Bodnar GPSDO
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TESTING THE FE-5650A RUBIDIUM STANDARD AGAINST A LEO BODNAR GPSDO The simplest useful test is to compare the FE-5650A 10 MHz output directly with the Leo Bodnar GPSDO, also set…
Rubidium Time Standard
Comparing 5650A Rubidium Source with LBE-1421–23/9/2026
Video showing measurements: https://files.ad.thornett.net/astronet/5650A_vs_LBE-1421_measurements_230926.mp4 Long video showing drift of Rubidium 5650A time source in real time against the Leo Bodnar LBE-1421 GPS-disciplined time source (1 pps not used): https://files.ad.thornett.net/astronet/5650A_vs_LBE-1421_long_drift_video_230926.mp4
Comments on using Leo Bodnar LBE-1421 to produce 1 PPS output
Andy, First, I’m just curious why your focus on the 1‑second PPS output. Nearly every GPS module provides a PPS signal, so unless you specifically need a programmable frequency synthesizer,…
The Leo Bodnar LBE-1421 provides a 1 PPS output that can be used as a long-term GPS timing reference, while allowing the FE-5650A rubidium oscillator to provide the very stable short-term frequency, in a combined time source
You can use the 1 PPS as the long-term GPS timing reference, while allowing the FE-5650A rubidium oscillator to provide the very stable short-term frequency. Conceptually: The key point is…
Need to add heatsink to FE-5650A rubidium time standard
Hi Andy, I wanted to pass along an operational caution about the FE‑5650A that may not be obvious from normal bench testing. This particular rubidium unit dissipates a very large…
A PLL’s LOCK indication is often mistaken for proof of true synchronization, but in reality it only confirms that the loop is operating within its internal lock window.
A PLL’s LOCK indication is often mistaken for proof of true synchronization, but in reality it only confirms that the loop is operating within its internal lock window. A rubidium…
How does rubidium locking link to PLL?
Yes — rubidium locking and a PLL are closely related ideas, although the atomic-lock servo is not necessarily a conventional electronic PLL in the narrow sense. Think of it like…
What does it mean to be locked in my rubidium time source?
In your FE-5650A rubidium frequency standard, being “locked” means the electronics have successfully tuned the oscillator so that its frequency is being controlled by the rubidium atoms, rather than merely…
How does rubidium time source work?
A rubidium time source is slightly misnamed: fundamentally it is an extremely stable frequency source. Your FE-5650A, for example, produces a very accurate output such as 10 MHz. Electronics can…
Effect of changing the pull-up resistor connecting the lock indicator pin on the rubidium 5650A time source DB-9 port to +5V supply from 4k7 to 20k on 13 September 2026
Voltages measured have changed to these new values: 2.865 V unlocked 0.264 V locked (Previously were 3.8 V and 1.001 V with 4k7 resistor)