I do appreciate that you did show the table (which is why I do tend to use RG-6 in situations where I can use a 75ohm plug that will work with a 50ohm jack).
My main concerns with the setup as illustrated would be that there’s some areas that do introduce additional loss that might cancel out the RG-6 advantages:
a) My biggest would be with the N-to-F adapter on the antenna. If that is not specifically a 50ohm N to 75ohm F, you have pretty much the same issue I mentioned earlier–a 75 ohm N plug has a thinner inner conductor:
The tolerances ARE different enough that inserting a 50ohm N plug to a 75ohm N jack is capable of damaging the jack–and a 75ohm N plug in a 50ohm N jack is not going to make good mechanical or electrical contact (and thus is not going to work as well as with a 50ohm N plug :D).
In my experience, N-to-F adapters tend to be 75ohm all around, and I do know the FlightAware antenna is actually using a 50ohm N connector.
b) The F-to-SMA adapter also introduces some losses (not just from the adapter itself but the shift in impedances)–that’s not nearly as severe as the issue with the potential N connector mismatch, though.
The Cantenna of course doesn’t have the potential mismatch issue (as it uses a native F connector) and if the FlightAware antenna used some other type of connector at the base (BNC, SMA, pretty much anything really but N or TNC) I’d not really sweat the impedance mismatch for listening as that’s just a decibel or two. The worry I’d have is that the better performance of the RG-6 would be nullified by the fact the inner conductor of that N adapter’s just barely making contact at all!
TNC, this isn’t an issue (because 50ohm and 75ohm TNC adapters just aren’t cross-compatible at all!) but you DO have to watch this with N, and because of the fact there IS enough of a difference between 75 and 50ohm N connectors that one risks breaking something or having a bad connection by forcing things…I do try to match impedance with N adapters in particular.
Now, were I doing a similar setup, I’d probably be running LMR-400 if I reasonably could as it’s less attenuation overall, but if I couldn’t…probably a saner approach (that wouldn’t risk a dodgy connection with the N connector) is to get a specifically 50ohm N male to BNC female adapter, and then use a 75ohm BNC connector on THAT end of the RG-6 cable (yes, you can get compression-fit BNC adapters that work like compression F connectors, my usual go-to when dealing with scanner antennas is RG-6 quad-shield with BNC on both ends or BNC on one end and F on the other). The tolerance issues (and risk of breaking things) are nowhere near as severe with BNC as with N connectors.
To the original poster: I don’t know how close you are to some of the markets in Shenzhen/Guandong or Shanghai, but you could probably pick up a right angle N female to SMA male adapter (there’s a little loss but not quite as much as with an RG-316 pigtail; as your receiver is in a dedicated box with a bulkhead connector to outside I’m a little less worried about strain relief). Also you could probably have an N to SMA connector cable made up, I know there are plenty of places on both Amazon and Ebay here in the States that sell them and on Ebay in particular a lot of the sellers are Chinese based. (Alibaba and Baidu almost certainly have sellers if you’re not near the major electronics market areas.)
The cables might not be sold as LMR-400 or RG-8, by the way. Really high grade is RG-213, a common brand here in the States is Belden 9913, and you’ll probably see stuff like CA-400 or KRG-400 or the like. Same really goes for RG-6.