Originally Posted by Trickymissfit
the light bar for a PACT PC2 is 24" from the factory. Did you check the aluminum bar to see how straight it was when you set it up? That's a problem everybody I know that bought a 35 runs into. And with three screens; what are all those extra cables for?
Secondly I assume you did unplug the other two chronographs when firing the data. Otherwise the other two units will probably interfere with the one in use.
The extra cables in the photograph are the cables from the 7 different skyscreens I have mounted on my skyscreen rail. I wasn't shooting at the time of the photos. I simply draped the cables over the skyscreen rail while I was taking photographs to post in this Thread. There should be a total of 7 skyscreen cables. Three for the Oehler 35P, two for the Oehler 33, and two for the PACT.
!. All three units run and record velocity for each and every bullet fired - concurrently. This is the real value
in running chronographs in tandem or triplicate. Two, three, or in my case, four
sets of recorded data are collected for each bullet fired. This provides the additional data required in order to validate the quality of the data. There wouldn't be any good reason to shoot over mutliple chronographs if only one of them was used at any one time. I wouldn't bother purchase and setting up multiple units is I could only fire over them one at a time. Getting multiple velocities for each bullet fired is what it's all about.
As you can see from the data, no troubles or interference recording data with the cables plastic tied together. I recently corresponded with another Forum member from Colorado. He's running his skysreen cables for his Oehler 35P in one bundle and getting about 2-3fps differences between his primary and proof channel over a 6' long skyscreen separation distance with his 338 Lapua Improved. His ES is running less than 10 fps for his final loads. So with that kind of quality data, he's obviously not experiencing any problems with electrical interference.
I talked to Ken Oehler and his wife at the 2009 Shot Show in Orlando, Florida. They told me their current Skyscreen III units are better insulated compared to their prior generation skyscreens. He told me that the PACT skyscreen cables should not interfere with the Oehler skyscreen cables or operation. But I didn't ask either of them if they recommended bundling Oehler Skyscreen III generation cables together, or if that would be problematic.
Supporting your comments though, the PACT technician I talked with about 4-5 years ago via telephone told me that their skyscreen cables should be
kept separated. I've always done that my PACT until I set up my new Oehler 35P on this newly constructed (homemade) skyscreen rail. I've only shot the initial bullets over it that I posted data for earlier in this thread. So far - so good. But I appreciate your observations and comments, and I will keep that in mind if the PACT starts to act up.
I never even used the Oehler-provided 4'-long piece of EMT skyscreen rail that was shipped out with their 35P, so I haven't really inspected it for straightness. The first bullets I fired over the 35P were over my homemade 6' 8"-long skyscreen rail. Also, I've never used any PACT provided skyscreen rail. I prefer to shoot over skyscreens separated over a 5 to 6 foot distance, in order to reduce the error associated with slightly inaccurate skyscreen separation distances.