far-trader
Mongoose
...back to the original topic 
I've wanted to reply to this but haven't really been sure how, or even if the answer would be sufficient.
In short it's up to the ref to flesh out the aspects of higher tech, but there have been tables with more examples and guidelines than just guns and jump drive.
In CT LBB3 Worlds and Adventures there is a table breaking down significant items by TL covering Weaponry, Computers, Communications, Transportation, and Energy from TL0 through TL17. Granted the table is not filled and leaves room for TL18 through TL21. I have penciled in notes in my copy (The Traveller Book actually*) of significant items under most categories across the whole TL band.
* which added a "Miscellaneous" column and some additional notes in the other columns
My penciled additions are a mix of personal ideas and borrowed from JTAS and such.
MT went even further in fleshing this out iirc. Including items in the build section up through TL21.
So, for me, yes the TLs are different enough. Never had a problem imagining differences between them, and I always noted each item of gear my character had with the TL it was made at and usually came up with how that made it different from the same item at other TLs.

Mithras said:I think I've always had this problem ... I can instantly conjure up images of what a TL 6 or 5 or 7 society is like, transport, medicine, etc and the implications based on the planetary characteristics.
Past TL 8, it gets fuzzier, but after TL 10 Traveller's TLs seem to blur together. Grav vehicles, high energy guns and jump drive seem to typify TLs from A to F.
Can we match up higher level Traveller TLs with the tech from novels or films? Or can we fill in extra items, breakthroughs, inventions for these higher TLs?
What kind of tech could be expected at TL 16, 17 and 18? Do they match Star Trek, or some other famous sci-fi universe?
I've wanted to reply to this but haven't really been sure how, or even if the answer would be sufficient.
In short it's up to the ref to flesh out the aspects of higher tech, but there have been tables with more examples and guidelines than just guns and jump drive.
In CT LBB3 Worlds and Adventures there is a table breaking down significant items by TL covering Weaponry, Computers, Communications, Transportation, and Energy from TL0 through TL17. Granted the table is not filled and leaves room for TL18 through TL21. I have penciled in notes in my copy (The Traveller Book actually*) of significant items under most categories across the whole TL band.
* which added a "Miscellaneous" column and some additional notes in the other columns
My penciled additions are a mix of personal ideas and borrowed from JTAS and such.
MT went even further in fleshing this out iirc. Including items in the build section up through TL21.
So, for me, yes the TLs are different enough. Never had a problem imagining differences between them, and I always noted each item of gear my character had with the TL it was made at and usually came up with how that made it different from the same item at other TLs.