Multiple Gun Sensors

Re: two gun sensors - we've done this before where when we had access to an extra lynx camera - we will run them as a primary and backup, each with their own radiolynx and capture computer. The only issue we have, is you must boot the primary camera with the primary computer hooked into the LAN, (and the backup computer disconnected and the backup camera turned off) and then after it is booted, disconnect the primary computer from the LAN, and then connect the backup computer to the LAN, and then boot the secondary camera. After the secondary camera is booted, you can hook the primary computer back into the LAN. Oh, and make sure the two computers have static IPs that are spaced apart by at least 2 address. ie, Primary computer is 192.168.0.5 and the backup computer is 192.168.0.10.
On the radiolynx, make sure that the internal dip switches aren't the same for each system, and it should just work fine.
Re: camera capture at the beginning. I'm assuming you are using the ACM, right? This is how I use it, not for a 5k, but for 800,1600,3200 on a track. The advantages on a track is I can track each runner multiple times, even getting splits if I wanted them, but also solving mysteries of the missing athlete when it occurs. If I'm not evaluating live, I will start at the last runner and work my way back. Just be sure to have a backboard to prevent movement behind the capture zone from trigger the capture.

To be totally redundanty, you should use a different LAN for the backup-system.
It should also connected to a different power cicuit having it's own UPS...

Finish lynx will allow two different types of sensors on one system, EG, a radio lynx and a "hard wired" start. The hard wire could also a radio system that plugs into the C-box 3pin connector labled "start". You can split the signal of a system that goes into the start connector on the C-box and have that feed two or more systems It is better to use two networks to have them independant. Two Radio lynx systems should have different channels for two different cameras. You change frequency on the radio Lynx with the dip switches under the caps on the back of the radios. The above discription by DudeMan will work if you want to have the back up on a single network but I would have the static computer addresses with much greater difference. That means the last series of numbers in the address having more than 80 difference. If one camera or computer goes off during the meet to get the two systems working again, you have to go through the entire start up and stop the meet for that period of time.

As for the continuous capture, if you have the drive capacity, go ahead and do it. it gives an entire history of the race that you can produce lap times from.