Korttelirastit Heureka

Start -> #1: along the rail-road in front of Heureka, then along the street might have been better. My route is more scenic along the river.

#5->#6 route choice between left or right side of the rail-road for the long straight bit. Close to the control I slow down at the right smaller road/path towards #6 but then I fail to make the turn there.

#8->#9 and #9->#10 on both of these legs the left route choice seems better in hindsight. Especially my S-shaped route to #10 does not look good.

6km course, 9km route in 48min48s or 5:22/km. 11th out of 86 runners. Around +2 C, windy, and snow/rain at the start.

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Korttelirastit, Hakaniemi-Kruunuhaka

Sprint-O on familiar streets today. The 5 km course was composed of two sprint-courses, 2.4 km in Hakaniemi and 2.6 km in Kruununhaka. I didn't use a compass today ;)

The Polar V800 GPS did not work great on the Hakaniemi map and I had to correct the GPS-trace a lot to get this result. Mostly OK going, but out of #12 I took the wrong path down from the control-hill, assumed I had hit the right street leading towards #13, and ended up close to the forbidden area (Hämeentie). Green arrows show the correct path, probably up to 2 min lost here.

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On the second course I didn't make any major mistakes. #3 was hard to say if it was reachable only below from the sloping hill, or also from the top along the much easier terrace with a fence. I took the slower path from below and then climbed the fence after finding the control. The way out from #8 towards #9 seems awkward and slow, but maybe there is no route directly south out of #8?

Total time 47min 22s for both courses. 12th place out of ca 63 runners.

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DIY DSOXLAN

Let's say you have a DSO-X 2000 or 3000 series oscilloscope and you're not super keen on paying about 300 euros for the brand-name DSOXLAN module to enable the Ethernet port it already essentially has on board? No worries, just build yourself this DIY DSOXLAN module! The most expensive part of this build is the 8 euro magjack Ethernet connector.

Sources: https://github.com/aewallin/DSOXLAN

In other news this blog has been updated to WordPress 4.1. Hope everything works OK.

SMD R/C kit

  • Inspiration and labels from: DIY SMD Resistor Capacitor Kit. I enhanced the labels with tolerance and wattage/voltage infromation as well as color-coding.
  • Boxes: www.shenzhen2u.com
  • Components: Digikey
  • Resistors 1x, 2x, 3.3x, 4.99x over 5 decades from 10 Ohms to 100 kOhms. All 0805 size.
  • Capacitors: 4.7x and 10x over 7 decades from 1pF to 10uF. Smallest 0603, mostly 0805, and largest 1206 size.
  • Bugs: X7R is misspelled as XR7. One printed label was lost in production. My choice of components uses 36 out of 40 boxes - still room for 4 more components.

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Agilent DSO-X 3034A

I got a 4-channel 4 GS/s 350 MHz Agilent DSO-X 3034A scope on ebay!

So far I've just explored the Easter eggs built into the firmware :)

White Rabbit Switch PPS-output test

We got some White Rabbit Switches and I did an initial test of the pulse-per-second (PPS) output stability. In contrast to earlier measurements that showed 200ps or so of white phase noise, the PPS output on the WRS now seems a lot more stable. For various reasons the noise-floor (red data) of our 53230A time-interval-counter is at around 50e-12 @ 1s, and the WRS PPS output is at very much the same level of stability. Another 53230A counter shows about 13 ps standard-deviation for a cable-delay measurement - so I may redo these measurements with that counter. In any case a real evaluation of the short-term stability requires a DMTD measurement at 10 MHz.

53230A counter input channel fix

Update: after the fix the counter seems OK again. 12 ps standard deviation (61k PPS-pulses, collected over 17 hours) on a cable-delay test:
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53230A_fix

A broken CH1 input trace seems to be a common problem on the Agilent/Keysight 53230A counter. This is the second unit with the same problem we have seen.

The fix is to bypass the broken trace with a wire directly from the center of the input-BNC to the next unpopulated SMD-pad.