Just out of curiosity, what AWG do most hills use for their start wire? AWG22? AWG18? What is the max wiring resistance above which operation of typical headsets and timers is affected?
Thanks.
-- Mark
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Most multi pair telco type cable used is 24 - 26 awg. A typical slalom hill with fresh cable and boxes will ring out at 25-60 ohms. GS hill at 60=85, Super G - DH at 85-110 ohms.
Here is a handy table
Of course nothing is perfect and you results could vary. Remember too that cable stretches over time and the resistance values increase as the effective AWG decreases.
Thanks. That's good info,
From the timing room to the top of our SL hill at Cochrans is 2000' which measures at 42 Ohms with 22 awg. Add another 300' (5 Ohms) to the top of our neighboring race trail.
We have 6 pairs, and so I did a test in which I shorted 3 pairs to each of the other 3 pairs -- so 3 pairs of pairs which were double length (4600', ~100 Ohm). I then connected one end of the 3 pairs to the A output of a start gate, and the other ends to 3 separate channels of a TIMY3. All three channels gave the same TOD to within 1/10,000 sec. That gives me confidence that there's no problem with a 100 Ohm start wire, let alone the 50 Ohm that we have.
-- Mark