Just what do you think a tuner is...
it is a mis conseption in how many think it will enable them to talk on any antenna..
the slight ALMOST Exception is say
you are looking to transmitt on say (i will use 11 meters here)
27,775..
say your antenna (vertical or horizontal) is tuned as many are half way on band of 11 meters 26,985 to 27,405.....
so half way is about 27,200 (not a exact figure)
depends on how wide banded the antenna is for us to realise how a sinals effectency drops as one steps out of the sweet spot
lets say is 1/2 a meg (so 27,200 down to 26,700 on upper end to 27,700).......so basiclly any frequency on that antenna will sound well from 26,700 on up to 27,700
so now i put my tuner on and ajust the frequency i am using
27,775 ...
i am so little off to start with little difference would be realised with a tuner.....and i really would not need a tuner if my swr had been say 1.1 to 1 (i can see at times using a tuner to help you hear better...that is a different discussion)
now take same antenna but instead of 1/2 meg bandwidth say it is .2 meg
now using 27,775 puts radio usable within its bandwidth very well within entire legal cb freuency's
this is still within easy use of a tuner.....some antenna will drop their 1.1 swr to maybe 1.3 at the 27,775
now your wattage effentcy is (say was 10 watts at 1.1 swr)
at 1.3 effentcy drops to likly 9.5 watts no big deal here
now say antenna you are using has a swr of 2.5 or say swr of 3
now radio likly willnot like it....
our ten watts drops to what...something like 5 or 6 watts
again is radio going to notice a huge difference here...maybe...likly not
but your transmitt dropped what...almost 3 db (that actually is huge) though at the 10 watts we started with it is doubtfulll whether the radios finals will have problems
if we jump instead to say 500 watts....
well now it is impotent to use the tuner for now the finals will indeed not like this and are in danger of going with repeated use of such a poor match....
so you win using the tuner.....
sort of.......radio/transmitter is safe
but the reduced effiency is still present
with the true swr of 3 using original lenier/amp pumping 500 watts....in actuality is realisticly effectivly radiating 250 watts (whatever the true formular is....would have to look it up....doing this from memory......i do not use linears and make sure my swr is spot on (so no need to use tuners....i use tuners only if swr rises...then realising i have problem with antenna,coax or coax connector....therefore will protect radio so i can still use...untill such time i can go address the problem in my antenna system....yet in using my tuner at these times ,,,,which is few and far between....i realise i have reduced my actual usable or effective power output)