right some people think i'm anti-atus i'm not anti-atus i just think that sometimes we are
sold stuff that we don't need all right we do well potentially we need something but let me
let me take you through my thinking so from the 40 meter band upwards most
sections of the bands that we operate in uh like a dipole or a vertical will they'll have enough um
bandwidth to be able to do let's say take the 40 meter band so 4g uh let's take a 20 meter band so
20 meter band is by the way ignore my purple nail polish they were having fun as a family but it got
hard and apparently i've got to let it dry and then we can take it off i don't know much about
nail varnish okay that's not the purpose of this video so let's take the 20 meter band it's a 14.0
to 14.3 now i don't know what percentage increase that is all right it looks about two percent to
me give or take but anyway i'm just saying even a oh no three that's 50 350 okay so it's the whole
bandwidth it banned is 350 small k big h little z or z 350 kilohertz now a straight vertical
for instance if that's 14 that's 14.35 and we've got an swr of let's say three here uh two there
one and zero you will find that the swr will be it's actually a bit steeper at the end there but
you will cover the hole of at about two to one swr you'll cover the hole at 20 meters and that will
be a dipole or a vertical for instance the same at all the other bands apart from the 10 meter band
which depending on part of the country but that can go from 28 all the way to 29.7 or something
that is is quite a lot in terms of megahertz but in terms of percentage
of the wavelength it's not as much as the next problem which is where you might need an atu for
the 80 meter band or america is called the 780 and the 75 meter band because in the uk we can go from
uh we go from 3.5 which is the cw and to 3.8 there we are now that that is a lot it's 300 kilohertz
killer hurts i'll try to make that small
300 kilohertz but as a percentage it's a lot okay so you'll find that
um a straight vertical or a dipole will give you somewhere between 100 and 200 kilohertz of that
just depending on a number of factors so you'd be lucky to go from three point six five to
three point eight your average joe antenna a bit of wire right i mean and that's stretching it
at sort of two to one swr as if you want to go lower all the way down to the proper with the c
proper proper part of the band the cw end of the band then you'll have to engage some sort of uh
tuning in here just to take the mismatch away between the coax and the radio now this isn't um
some sort of tuners are bad balanced feeders are good blah blah i'm just saying that your
average joe's got a piece of coax into the backyard back garden he's going to
have a problem with that if he ever gets on 160 the problem becomes even more serious
is as a percentage of the band from one end to the other becomes even tighter all right
it basically doubles every time you go up or it harms every time you go down basically
so when do you need an atu if you're serious about 80 meters now i don't i've got an atu but i
don't run it because my antenna i mean it's just a vertical it's got a coil in it and i go from about
3.68 to about 3.78 at 2 to 1 swr between the two
so i'm i'm at about 3.74 is roughly my sweet spot you see so i don't need an atu for that
but if i wanted to do f because that's ssb portion of the band if i wanted ft8 which is down below
3.6 i seem to remember then my swr is going to be 3 4 1. by the way i've looked at the chart here
right i mean this this happens to be i just did i'll show you i just did us a search power loss
swr chart there's plenty of people that copied this for me he hasn't invented this he's copied
it from somewhere else so if we look at three to one swr i'm getting 25 percent loss okay so 75
percent of my power is going out the door at six to one right which is actually quite a big swr
i'm a half half my powers going out the door all right half the power is definitely going out the
door well that's not bad i mean i've got 200 watt radio or the 60 meter band and i haven't
got an antenna tuned for that i happen to know my sw i was about six to one well that's all right i
could run um 200 watts how many radar i think i'm only allowed 100 watts at the other end anyway
uh 61 swr i engage the atu button and most modern radios will go up to about a 10 to 1 swr
i don't know my ts2000 doesn't i think the ts590 has got a problem with that but yeah there's some
loss on the line but it's no big deal you still get out you'll still receive okay that's the point
so before you go out buying atu matching units and everything else i think the biggest question
is what sort of antenna i want to run you know a fan dipole will give you a perfect match to coax
on 40 20 15 and 10 for instance now i'm not selling you my dx commander product but you know i
mean i designed that because i didn't like atus it and it's not i didn't like them i didn't want the
extra kit to take away my holiday and i didn't want the extra cost so i designed an antenna i
didn't need any of that with this will give me a match on every band just give me one to one sword
thereabouts 1.5 do an swr 1.5 swr oh big deal i'm losing four watts out of here every 100.
there we are i've waffled enough it's just food for thought before you go and buy a atu think to
yourself maybe i could just change the antenna maybe i can put another bit of wire in maybe i
can invest in a nice piece of coax and just drive my atu button on the radio because unless you're
running a transistor amplifier transistor amplifier you shouldn't actually need an atu
um let's say you've got a modern radio there's an atu button and that will take out most of
this it'll still let you operate and if you find actually i'm spending most of my time
on fta on at 80 meters we'll tune the antenna down there and for ssb hit the atu button
there we go right if you think this is of value to other people then giving a
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coverage and why not have a jolly good day thanks for tuning in i'll see you next time bye for now