LMH6609MA and LMH6702MA

Opamps, in SOIC-8

Merged #1233 into master.

Compact frequency distribution amplifier

Stefan DK3SB, sent me this picture of his version of my frequency distribution amplifier. He modified the PCB to make it narrower (160mm), to fit a  Hammond
1455R1601
enclosure (about 25 euros from Farnell).

Nice work! KiCad sources and gebers hopefully to follow, on ohwr.org

KiCad footprint: Molex 73251-2200

Merged #1116 into master.

19" rack-mount for 7" R-Pi screen

An old drawing from the archives, which we hereby archive here. Drawn with Schaeffer front panel designer. Requires a further PCB-bracket that attaches to the 230x100 M3 holes and has screws that reach the back of the 7" LCD module.

Distribution Amp - S/N 16

Update2: Here's the 14-hour data together with a 14-hour noise-floor run. The ADEV and TDEV results are more or less instrument-limited. Only for phase-noise above 100Hz offset is the instrument floor significantly below the result for the distribution amplifier.

Update: Here's a 14 hour run of the residual phase noise, ADEV, and TDEV, as measured through the frequency distribution amplifier. Instrument is a Microsemi 3120A phase-meter.

Aivon has now produced around 16 of these distribution amplifiers.

There's a new op-amp which might be interesting to try for the FDA board: THS3491. It has a grounded pad under the op-amp, so we need a new EP-variant of the PCB.

KiCad symbols and footprints

Update: Molex R/A 'long-neck' SMA-connector:

Silkscreen only on board, F.fab drawing shows off-board threaded part.

I sumbitted a few pull-requests to the KiCad libraries with some parts used on recent boards. Let's see if/when they make it into the main/released libraries...

On the to-do list is to submit an SFP-connector and Cage footprint... (unless someone has already done that?).

Rabbit @ NIKHEF

Learning about WR absolute calibration at NIKHEF, Amsterdam.

Pirttibacka 10k feat. Giant's Kettle

The loop marked with yellow signs from Pirttimäki is about 8 km, so we did some bonus-metres to the south of Sorlampi to get a full 10k. As a bonus we looked at the Giant's Kettles just north of Sorlampi (arrow-marks-the-spot).
Although the weather is warm, around +6C maybe, It's fairly dark around 16-17 already 🙁

Noise Colours - again

Inspired by discussion on time-nuts, here's a revised noise-colour graph. There are a few updates: The PSDs (both phase and frequency) now cross at 1 Hz (with the relation between phase-PSD and frequency-PSD explicitly stated), and the ADEV/MDEV theoretical lines now include the formula for the pre-factor (the old graph only had 'proportional to' here).

Source: example_noise_slopes2.py

Simulated time-series with power-law noise. The relation between phase-PSD, frequency-PSD, ADEV, and MDEV is shown.

It is left as an exercise to the reader to properly explain the ADEV pre-factor for flicker-phase noise :).

Oittans-Solvalla-Oittans

Might be some of the last weekends this season for biking in decent weather... Mostly easy but hilly gravel paths from Oittaa heading north to Solvalla, then back south along the main road.

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