2495mm is from center pin to center pin distance right ?
2495mm is from center pin to center pin distance right ?
I did see Coherent documentation that VSWRFault can indicate on the first firing attempt, like for the first second, if the tube has not been used in the last few hours. The gas actually does have difficulty ionizing and the output will be low and unstable. The VSWRFault is indicating ionization probs as intended, but it might not actually be a failure in the tube just a brief, transient initial stall.
Wow, always wondered about this. Hey, what cable type is used with these on a Coherent? I have an orange aftermarket cable marked "E170516-7 CATVP (11AWG)"
I went looking and found someone with E170516-7 cable, but it say "6AWG". This is strange, I would think a different gauge would be a different part number entirely. This also begs the question, is this 11AWG orange aftermarket stuff necessarily the best choice for the task? The 6 AWG would be thicker, but resistive losses in the copper may be insignificant to begin with. I don't know if the 6AWG would even fit inside the RF crimp ends you list.
The stock Coherent cable is notably thinner outer diameter than this aftermarket 11 AWG.
I have an orange cable from coherent. LMR400 is what coherent uses, going heavier would do no good. 400 can handle about 2kw at 100MHz
These power supplies are incredibly sensitive to mismatch. Literally a couple inches can cause a head from firing reliably to not. I had made one that was a couple inches too short and it would not fire reliably and added an elbow and a nipple to route the cable which brought the cable length to where it should be and it runs perfect every time.
The E numbers are not a good number to use for finding wire, its mostly a identifier. You need the other numbers on the cable, like I mentioned above, LMR-400 is used for the smaller coherent heads, my Rofin uses LMR-600
OK, I think you're right! I have an OEM Coherent cable that is thinner with a braided silver metal shield as the outermost layer. I don't see any marking for the coax itself, like you'd normally find printed every foot or whatever to show what type of coax was used to make it, because it's a braided metal jacket and that's not practical to mark.
I'd gotten it into my head that the orange cable was aftermarket, but no, there was no reason to think that. It's OEM from a different period. It is labeled LMR400 further down, neat!
Hi,
I know this thread is almost a year old, but I am looking to use a NanoVNA to build a cable for a Coherent laser.
What aspects of the Smith chart were you looking at exactly, the green Marker 1?
Meaning if the marker is above the horizontal it's too short, or below the horizontal it's too long?
If this is the case, you then just kept cutting back until the green marker was on the horizontal at 0 degrees?
Yes, the green. Make sure you compensate for any adapters you put on there.
I dont remember if too long was above or below the horizon. You could add something to the end and see which way it moves it.
Thanks for confirming, it's appreciated.
I had a machine and its laser pointer not directed to the center, it always miss my expectation output, I'm will not promote this machine. It's not worth it.