hi everyone thanks for clicking on the
ham radio crash course my name is josh
amateur radio callsign ki6naz
today i'm going again back to kind of a
beginner
video i figured since i've got a
specific radio with me right now
that i might talk about tuners
specifically
manual tuners you know we mentioned
automatic tuners a lot but
there's a lot going for a manual tuner
so today i'm going to show you how to
use
a manual antenna tuner
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a couple of things to note about a
manual antenna tuner is you're going to
have to adjust them as you change
bands just like an automatic would as
well but
you're obviously going to go hands-on
with it they're also generally
far cheaper and with them some of the
larger ones that
would sit on your desk or whatnot will
actually have
a wider impedance match you can do so
you can take something that's
way way out of match and and bring it in
with the manual tuner
there are die hard enthusiasts of manual
tuners and they won't
work with automatic tuners at all and
there's good reasons for it
a lot of it is they're just not that
difficult to use and they can be
effective and they can be
acquired very cheaply and easily
all right here is the mfj pocket tuner
most tuners are going to look something
like this there'll be a control for
inductance
this is a multi-tapped switch basically
and then there'll be two potentiometers
that you can control for antenna and
transmitter
there'll be a port in antenna in and a
port out for the transmitter
in and out is is relative of course you
understand
tune and bypass bypass just treats this
as a bypass it just connect makes the
connection between these two ports and
you're done
tune however allows these controls to be
come into play so let's go ahead and
connect the radio i've got my antenna
connected this is an n-fed
and here's the line that goes to the
radio down here all right so i have it
on
a for inductance and 0 0 for transmitter
and what i'm going to do is let me just
show you the reaction don't mess with
any of the antenna transmitter controls
yet
just cycle through the inductance watch
the noise floor creep up
as we start to hop around keep an eye on
the s-meter here
and the pan adapter
or the spectrum scope whatever you want
to call it
and there it drops down again when you
hit b so we've got some high points
i would say d is probably the highest
with e being close second
f and then it starts dropping down again
so what you're aiming for is you're
aiming for the highest noise floor
so let's let's go back to a just for the
heck of it i'm in
am mode you can do this with a cw mode
with a straight key
and you just hold it down and let's see
what the reading is so it says
9 to 1 swr so that's pretty bad let's go
to d
and we'll check again not touching these
controls yet
1.8 to 1. so we've already knocked down
a huge amount of the standing wave ratio
the match misconnect if you will the
mismatch
between the antenna and the transmitter
just by getting the inductance on d
so you can sort out most of your
problems just by looking at your s-meter
and adjusting it appropriately but let's
fine-tune it
so i'm not going to really mess with the
antenna we're just going to i'm going to
show you what it looks like to mess with
it
so 1.8 watch what happens when i adjust
the antenna swr climbs
so we don't want to do that instead
let's go to the transmitter and adjust
it
and it's dropping and right there
1.1 1.1 1.2 to 1.
we just tuned the antenna well let me be
specific
we're not tuning the antenna we're not
tuning anything
this box is creating a match
between the mismatch of the antenna and
the 50 ohms
that this radio expects that's what this
box does
it just creates a 50 ohm impedance
so that the radio can put out all the
power
into this box and and have it go out of
the antenna
that's really what it's doing alright
here's another way to display this
i want to mention this while we're
looking at these devices you don't want
to be
keying up putting out rf out of your
antenna
going into the tuner while modifying or
adjusting inductance
don't do that okay don't do that instead
if you're if you're unsure about the
noise floor the other thing you can do
is just
rotate the inductance once click it and
then check the swr
2.2 not bad let's go back to where we're
on which is
g 1.3 to 1. you see that
right there very low so that's all you
really have to do to get kind of a fine
check just work your way through the
inductance
and check the swr there you go 1.3
let's see if we can do a little bit
better with this let's go in there and
adjust it some so 1.3
now there we go one to one
so we were able to drop that down to one
two one match setting the inductance to
g on this tuner and then given a little
bit
of adjustment on the transmitter side
remember don't adjust this
while you're keyed up don't do that you
could damage the tuner
a couple of things to note here this
mfj940
it'll go all the way up to 300 watts to
match that's
that's really good this is an
inexpensive tuner very small because
it's it's all manual
you don't need the automatic control to
be able to adjust the matching network
inside
and this is just a push button thing and
i fed it with 12 volt power supply but
you don't have to it just lights up when
you don't have it
anyway that's pretty much how it works
manual tuner is pretty simple
so that's it for me today please post in
the comments
your thoughts about manual antenna
tuners do you use a manual antenna tuner
are you potentially going to pick one up
to do whatever
activations or radio fun you have
planned
we have a couple radios coming out here
not too soon with the tx 500
and obviously the icom ic705 that don't
have
an internal tuner so you may be looking
at something like an automatic tuner
well manual tuners can also fill that
role and they do so
relatively cheaply anyway love to hear
your thoughts i'd love it if you gave me
a thumbs up on this video if you have
not already please subscribe
i live stream every saturday at 5 p.m
pacific standard time
and i'll talk to you later see ya so
again thanks for watching i hope you
give the video a thumbs up please
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thanks again for watching and i'll talk
to you later see ya
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