We (Whitetooth Race Teams)are presently using Tag
505's and 705's for timing. What is the maximun line resistance these clocks will function at.
Thanks
Dave Webb
Kicking Horse Mountain Resort
Golden B.C.
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Good question. Line resistance is a little tricky insofar as it changes due to temperature and the condition of the wiring splices and connections. A perfectly good connection at 0 might come completely apart at -20. ALGE timers can tolerate resistance up to 700 ohms but we would typically like to keep the maximum at under 300. A good wire run for a world cup downhill is around 175 to 200 ohms. When checking your wiring look at the splices first. Scotchlok type connectors tend to open up at extremely cold conditions. We started twisting the wire and using "white beans" after having some issues. Your best option for an immediate answer would be to email Bert at TAG in Switzerland. Normally Ted Savage could answer this for you but he is at the FIS conferences for the next 2 weeks.
Bert.Wilschut@tagheuer.com
Bert.Wilschut@tagheuer.com
I was the main cabling guy for the Salt Lake Olympic Alpine Ski events, which is meaningless except that it does provide a baseline measurement for the ultimate hill cable setup, particularly on a DH course! The Men's DH was a 2-year-old network of 4 miles of 400 pairs (200 for A-System & 200 for B-System) of 22-ga direct-bury, mostly in 100-pair conduit. Due to an installation screwup the A system was on the Men's course and the B system was on the Women's course (slightly shorter). This was a screwup that we had to live with. Anyway, the max resistance from the Men's start was approx 120ohms, which was based on 4 miles with numerous buried splices for intervals and breakout bixes. Women's, despite the shorter cable, was approx 135ohms. Measured about 4 different times over 2 winters, there was no drift at all under all temp extremes (this is good). Bottom line is that your resistance will normally be impacted by several factors, in this order: 1) length, 2) # of splices, 3) quality of splices (i.e. waterproof), 4) cable grade.
If you think your cable is good, all you have to do is give it an annual checkup. You may only have a mile of cable, showing 300ohms resistance, but this isn't necessarily bad. As long as it stays consistent you know it's likely good. If on the other hand the readings drift by 100 ohms a year, lay new cable (figuratively speaking!). At Salt Lake we had the luxury of 200 extra pairs; most places don't!
Carry on
Andrew Allan
Alpha Sports Technologies
Sports Technology Specialists
www.alphasports.tv
If you think your cable is good, all you have to do is give it an annual checkup. You may only have a mile of cable, showing 300ohms resistance, but this isn't necessarily bad. As long as it stays consistent you know it's likely good. If on the other hand the readings drift by 100 ohms a year, lay new cable (figuratively speaking!). At Salt Lake we had the luxury of 200 extra pairs; most places don't!
Carry on
Andrew Allan
Alpha Sports Technologies
Sports Technology Specialists
www.alphasports.tv