I am using the internal tuner in my Ts 590 but still have my 
small external tuner in line that I used with the TS 480.  I have 
noticed that I don't get much action from the external tuner like 
I used to get when it was connected to the 480.  Seems like the 
internal tuner in the 590 is handling most or all of the tuning.  
My question is, can I take the external tuner out of the line? 
Thanks for your thoughts, Jim WA6EKS

 ----- Original Message -----
From: Bob Tinney <[log in to unmask]
To: [log in to unmask]
Date sent: Wed, 26 Nov 2014 21:15:50 -0500
Subject: Re: SWR, antenna tuners, and reflected power

I have to add something here,  I used to think that you had to 
have a
perfect match to maximize efficiency.  But I now realize that if 
you
have a good, wide range, antenna tuner, you can match almost 
anything.
You can even load up an 8 foot whip on 160 meters, but the 
radiation
efficiency will be very low and your tuner will get very hot or 
arc.  I
have an Alex loop that is 3 feet in diameter and it gets out
surprisingly well even on 40 meters, but you can only use up to 
20 watts
do to the close spacing in the tuning capacitor on the loop.

Bob, K8LR, [log in to unmask]

On 11/26/2014 4:24 PM, Tom Behler wrote:
 Ron:

 Thanks for the excellent concept review on SWR, reflected power, 
and antenna
 tuners.

 We all need reminders about this sort of thing from time to 
time.

 In fact, I'm now thinking of making some modifications to my 
station, and am
 trying to decide whether I can effectively do so with my current 
antenna
 arrangement.  As you may recall, I use an Alpha Delta DXCC 
nulti-band dipole
 on 40 through 10 meters, and a Cobra ultralite senior antenna, 
mainly for
 the lower bands.

 While these antennas have kept me on the air on the HF bands 
over the past
 few years, I do wonder sometimes whether I might try something 
else to
 improve my situation.  I do have limited space here, though, 
which makes the
 issue of alternate wire antennas a bit challenging.  A tower and 
beam are
 also out of the question at this time for financial and other 
more practical
 reasons.


 Anyway, your remarks are quite timely here, so thanks for 
sharing them.

 Tom Behler: KB8TYJ


 -----Original Message-----
 From: For blind ham radio operators 
[mailto:[log in to unmask]]
 On Behalf Of Dr.  Ronald E.  Milliman]\\`
 Sent: Wednesday, November 26, 2014 4:07 PM
 To: [log in to unmask]
 Subject: SWR, antenna tuners, and reflected power

 I am sure most of you know all about SWR (i.e.  Standing Wave 
Ratio), antenna
 tuners, and reflected power.  However, it might be worth our 
discussing it
 anyway for the benefit of those who might not be as familiar 
with these
 relationships as others.  Many of us use antenna tuners, both 
manual and
 automatic, for obtaining the best possible impedance match at 
the output
 point of our transceivers with the objective of getting the SWR 
as close to
 1.0 to 1 as we can.  A perfect match for most rigs is when the 
transceiver
 sees a 50 ohm load at its output.  Anything above a 1:1 SWR 
represents some
 level of mismatch.  Most of our transceivers can tolerate some 
mismatch
 before it begins to reduce the power output as a means of 
protecting the
 circuitry of the transceiver, and if the SWR or mismatch gets 
high enough,
 it will cause the transceiver to reduce its power output to 
zero.  Many of us
 have transceivers, like the Kenwood TS-590 and similar rigs, 
that have
 built-in automatic antenna tuners.  These tuners work extremely 
well for
 matching the impedance presented to the transceiver at its 
output, providing
 this mismatch isn't too high.  How much is too high varies to 
some extent
 from one make and model of transceiver to another.  If the 
mismatch is so
 large that the rigs internal automatic tuner cannot bring the 
SWR down
 within an acceptable level, you are faced with either adjusting 
your antenna
 to achieve a better match at the point where the feedline 
connects to the
 antenna, or you will need to obtain an external tuner to do the 
job.
 External tuners, whether manual or automatic, tend to have much 
wider ranges
 for matching the impedance of the feedline to the 50 ohms the 
transceiver
 wants to see at its output.  A match at the transceiver's output 
does not
 mean there is a match at the point where the feedline actually 
connects to
 the antenna.  Even if the impedance at the output of the 
transceiver is
 matched perfectly with an antenna tuner, there can be a very 
substantial
 mismatch at the other end of the feedline where it connects to 
the antenna.
 The larger this latter mismatch, the less actual power will be 
radiated by
 the antenna and the more power from the transceiver will be 
reflected back
 or remain in the feedline.  What happens to the reflected power 
depends
 largely on the type of feedline used.  The difference between 
the power
 radiated by the antenna and the output power of the transceiver 
is the
 reflected power and may be totally lost power, depending upon 
the loss
 rating of the feedline.  If coax is used for the feedline, this 
reflected
 power ends up dissipating as heat in the coax and is pretty much 
totally
 lost power.  If this heat is more than the coax can handle, it 
can burn up
 the coax.  In contrast, open wire feedline is considerably less 
"lossy", and
 much of the reflected power ends up being radiated by the open 
wire feedline
 as opposed to ending up being dissipated in heat.



 I am building up to two very important points that, in my 
opinion, do not
 received nearly as much attention as they should.  The first 
point is that
 reflected power is not good for your transceiver, or if you are 
using a
 linear amplifier, it is not good for your amp.  If you are using 
a tube-type
 linear, it can handle or tolerate more reflected power than the 
solid-state
 type amps, but regardless, reflected power is bad for your rig 
and it is bad
 for your amp.  Here is    my second point: just because your 
antenna tuner is
 able to get the SWR down to 1.0 to 1 or an acceptable level at 
the output of
 your transceiver or amp, that does not mean the reflected power 
is zero or
 reduced to an acceptable level.  Most rigs and amps today have 
built-in
 protection circuits that detect high SWR and high reflected 
power, and they
 will shut completely down if either the SWR or reflected power 
is too high.
 For example, I have a Kenwood TS-590 driving an Ameritron 
ALS-600, and my
 antenna is an 80 meter, full-wave loop.  I feed the loop antenna 
with 50 ohm
 coax and use a 2.5 to 1 matching ballun at the feedpoint of the 
antenna.  The
 loop works extremely well on all bands 80 through 10 meters, 
including the
 WARP bands.  However, there is a sizable mismatch on some bands 
at the
 feedpoint of the antenna.  Without an antenna tuner, this 
mismatch would
 present such a high SWR at the output of the transceiver or 
amplifier that
 the protection circuits would reduce the power to zero or, in 
the case of
 the amp, it would kick it off.  The mismatch is so high that the 
internal
 tuner of the TS-590 cannot handle it.  So, I use a LDG AT1000PRO 
II external,
 automatic antenna tuner, which has a much wider matching range, 
and it can
 handle the mismatch and the power of the ALS-600 just fine.  
However, even
 though I am able to get my SWR down to 1.0 to 1 on some bands 
and 1.5 to 1
 or better on the others, I cannot run the amp at full power 
because if I do,
 the reflected power is so high, over 50 watts, that it causes my 
ALS-600 to
 kick off.  Therefore, I am forced to reduce my output power down 
to the point
 where the reflected power is low enough that it won't shut the 
amp down.
 Consequently, instead of putting out 600 watts from the amp, I 
have to
 reduce the power to where I am putting out only about 300 watts.  
This keeps
 my reflected power level below 50 watts, which is the critical 
level for the
 ALS-600 amp, keeping it from completely shutting down.



 Many years ago, when I was a young, foolish teenager, I put up 
an antenna
 that had such a high SWR that I could get RF burns from the 
Microphone of my
 transmitter.  The transmitter was a Heathkit DX-40, which had a 
PI-output
 circuit that would allow me to load-up about anything for an 
antenna, but
 back in those days, there were no protection circuits to 
automatically shut
 the rig down if the SWR or reflected power was excessive.  As a 
result, the
 high SWR and reflected power from trying to load and extremely 
mismatched
 antenna caused my tank coil to get so hot that it melted the 
plastic
 insulators that separated the windings of the tank coil; this 
caused the
 tank coil to short, which, in turn, created a chain reaction, 
ending up in
 wiping out the entire power supply.  My point is to simply 
illustrate what
 high SWR and reflected power could do to your transceiver or amp 
if it
 weren't for the protection circuits that are built into the 
modern gear.
 However, even with the protection circuits, it is important to 
strive to
 achieve the best possible resonant frequency match with your 
antenna and
 then, between the feedline and your antenna and again between 
the feedline
 and the output of your equipment.



 I've had three people write to me off list asking me questions 
that related
 to this whole topic, and so, I thought I would simply write this 
up and post
 it to the list.  I'm not trying to show-off what I know; rather, 
I might be
 showing-off what I don't know because there is a lot more about 
this stuff
 that I know very little about, and I am absolutely certain that 
many of you
 know tons more about some of this stuff than I do.  I'm just 
trying to be
 helpful to some of the people that might be new that do not 
understand some
 of these things.











 Dr.  Ronald E.  Milliman

 Retired Professor of Marketing



 President: Millitronics, Inc.  (millitronics.biz)

 President: South Central Kentucky Council of the Blind 
(SCKCB.ORG)