These were purchased as a matched pair for a Mod 3 Binocular
I have noticed that as a general rule, there seems to be a rather linear relationship between the photocatode sensitivity and EBI. I see tubes with specs better than this but the EBI is almost always higher. Also, my own summer observing conditions can best be described as "hot" (90f at 11:00 PM is common), so a low EBI was important to me because the summer Milky Way is my favorite target. While I do think that EBI is a very important metric, I also think that sacrificing a lot of photocathode sensitivity to get it is kind of a mixed bag in terms of tradeoff. More on that in a moment.
Resolution is 64 lppm
Resolution is 64 lppm
Neither of these are what I would call super tubes, but when it comes to detecting faint nebula, I believe that they do well. The sky is practically black in the absence any stars and nebula, and I can see far more nebula than I ever realized existed. In particular, seeing that M29 sits in a nebula was a big surprise to me, and quite easy on a hot September night under dark skies. I have since duplicated this observation under red zone ski in August a 92 degrees Fahrenheit.
I have two other tubes but these do not have spec sheets, so I am going to give my gut feel based on having owned a surprisingly large number of tubes (mosty 10130 D/UV)
10130 D/UV (as a class, and all but one have been Omni VII)
SN: 23 to 25. I know there is much debate about the specs that the Omni Table shows, but I have compared these tubes to a true Omni VII level performance tube, and it is dead easy to see that the noise level on the 10130 D/UV Omni VII is simply not as good as a tube that really does have 28 SN.
EBI: Varies. Again, comparing to known tubes, I have owned tubes with EBI from 1.99 to .1, and I would estimate these to range between 1 and 1.5 or so. Again, one had EBI of 1.99, and this is at the edge of what one would want for EBI, and only on a cooler night. On hot nights, even though this tube had amazing gain and SN (or a PVS-7) it did not work well for nebula under these conditions. This was my big lesson on EBI.
Gain: Except for the noise and EBI, I can see almost everything in my PVS-7 that can be seen in and Mod 3s, so I am guessing the gain is quite good.
F9800VG (P43) spec tube (typical of that used in Military aviation goggles and equivalent to the 10160C/AVS Omni VI and Omni VII tubes)
Photocathode: Estimate is above the 2200 mininum spec.
SN: Minimum is 28. With the above info about the PVS-7 10130 D/UV above, in direct comparison (which I can do any night of the week because I own both) it is easy to see that the 10130 D/UV has considerably higher noise than the F9800VG type tube, which itself is very close to my L3 tubes. When filtered, the 10130 D/UV Omni VII is almost as limited by the noise as by the EBI. I was able to see Barnard's loop with every 10160 D/UV I have owned and of the four 10130 D/UVs I have owned (always in search of the perfect tube), all fell well short of the F9800VG spec tube (and the ULT spec tube) when it came to noise and especially when filtered.
EBI: In direct comparison, this tube has slightly higher EBI than the PVS-7 10130 D/UV I own, but much less than the PVS-7 with 1.99 EBI. I would estimate in the 1.5 range based on these comparisons
The F9800VG is outstanding on stars. It seems to show tighter stars with much more dynamic range than the L3 filmless tubes. The L3 tubes tend to flatten out the dynamic range in stars. They look more different for the size than for the limiting magnitude, with brighter stars having a bit more bloated appearance than in the F9800VG spec tube. In the then filmed P43 F9800VG spec tube, stars the pinpoints seem smaller for brighter stars, and when I view with it, stars jut have this brilliance that I find a bit lacking (by comparison) in the L3 filmess P45 tubes. In fact, what I used mostly for telescope work on non-nebula targets is the F9800VG spec tube. This tube conforms to the MIL-PRF-A3279602 standard, and this is the standard that is used to select tubes for military aviation goggles. In other words, this represents some of the best thin film tubes made. The military wanted people flying multi-million dollar airplanes to have the best.
Where the F9800VG tube type really excels is in high light resolution. Once again, the L3 filmless tubes kind of look flatter in response in high light. If you made me pick a tube for general NV use, this would probably be the tube I would use (My first Micro had the NV Depot ULT grade tube which had better specs and lower EBI, and I wish I had not sold it.)
I know that this was supposed to be just about the specs, and I hope people don't hate that I have included a lot more in my post than just the numbers, but the point is that the numbers don't tell the whole story. Tubes do behave differently and while everyone wants thin film white phosphor tubes, I would say that having used both, I have gravitated back to the F9800VG spec tube for most of my non-binocular observing. It is an amazing tube. I look at the sky, and stars have amazing dynamic range and sharpness.
I think low EBI is important, but I would not throw SN, Gain, and Photocathode sensitivity under the bus to get to .1 EBI. In comparison to Peter's tube, I can see that for most targets including even fairly dim nebula and on cooler nights, his higher spec tube, even thought it has a higher EBI, is a better tube. On a hot summer night though, I can eek out nebula that still surprises me. The rest of the year though, I wish I had Peter's tube.