Antenna tuner question.

[King Mudduck]

If i were to use a high quality antenna tuner and an say an Iamx 2000 could i talk on just about any channel a ham radio has? The reason i'm asking this is that i have often wondered if a tuner has limits as to what it can do with just any antenna a cber would use. I know that it will with a antenna meant for ham frequencies.

I seem to remember reading somewhere that even though you could do this that it would eventually mess up the tuner.

 

[rfoverlord]

Well without getting into a lenthy discussion, basicaly a antenna turner is a misnomer it doesn't tune the antenna per say but makes the radio happy so that it generates full power. That said if you were to take a reading at the antenna you would find that the swr was through the roof and your radiation efficency was a fraction of what a properly tuned antenna for a particular frequecy would be. I don't know if my old post is around here on using a star duster 10-20 meter yeah it'll work with a tuner just not well, iv'e used an empty beer can on a tuner to talk across town (11mtr) just to prove it could be done.

 

[W5LZ]

It's easier to understand if you think of that 'tuner' as a variable impedance matching transformer. Basically transforms a wide range of impedances to something close to 50 ohms that the radio wants to see. They all have limits to how far they can 'transform' things no matter what their cost/quality. Antennas bigger/longer than called for are much easier to match than antennas shorter than called for. So, if that 'Imax2000' is something like almost a 1/4 wave length on the band you want to use it on, the average tuner will probably make it work. If the antenna is much shorter than that, while some tuners could still make it 'work', it just won't work very well. Trying to use that 'Imax2000' on 40 or 80 meters would almost certainly produce a signal. But so would a dummy load, and probably better, you know? There are limits of usefulness. A tuner with a really wide useful matching range is going to be BIG. It has to be cuz of the size of the required components. Not because of the power applied to the tuner, but because of the required reactances and the resulting voltages from that impedance transformation. The voltage is the 'killer' part, as in arcing, and the heat from same. There you go, more than you ever wanted to know about tuners. (Ain't selling mine!) - 'Doc

 

[King Mudduck]

Thank you both!

 

[King Mudduck]

Been thinking about this today....

So what your both saying is that the tuner is fooling the radio into seeing a well tuned antenna but between the tuner and antenna its still crap? If that's the case then why even spend the cash on an antenna tuner if your still loosing performance?

....seems like a wast of money to me.

 

[SR385]

The tuner makes the finals in your amp happy, it's important.

Also, the most efficient antennas are narrow banded and resonant on a single band. A tuner allows you to 'stretch' the bandwidth, very convenient to be able to get a bit extra reach to band edges.

If you are talking about wide range roller inductor tuners, they can match up some very flexible antennas for restricted spaces or general convenience if you feed the antenna system with balanced line...which is FAR more immune to losses due to high SWR.

Take a 135' dipole or more accurately a 'doublet' when used on 80m through 10m. If you use a roller inductor tuner and feed that antenna with open wire line, proper balanced line, it can work quite well and be pretty efficient on all of those bands. The tuner keeps your amp happy matching the feedpoint impedance (really what a tuner does) and the open wire line minimizes losses due to the very high SWR that is being matched.

If you try to use a tuner to wide band match the wrong antenna system, it may present a nice impedance to the amp, but the losses will be very high. In a nutshell to answer your last posting, if you are matching something so far out of band that isn't designed to be...what would you expect? In that instance the antenna system is just improperly designed.

 

[SR385]

Another quick one to add.

If you have an 11m rig and what is supposed to be an 11m antenna, you shouldn't need a tuner. If the antenna system is properly designed it should just wire up and work.

A LOT of people have mistakes in the antenna system that they then cover up with a tuner.

 

[King Mudduck]

This is not something i'm going to try. It was just something i was thinking about and wanted to see if some one could give me an answer, i just wondered if it would work or not. Thanks for the info guys, i really appreciate it!

I guess this is why that a few hams that i know have a yard full of antennas

 

[555]

This is not something i'm going to try. It was just something i was thinking about and wanted to see if some one could give me an answer, i just wondered if it would work or not. Thanks for the info guys, i really appreciate it!

I guess this is why that a few hams that i know have a yard full of antennas

if you have one antenna and say on 11meter its 1.1 swr
then on another band its shows its a 3.4 swr
you put a tuner in line sure twist and turn the dials watch the magic happen swr drops down to 1.2
from your radio the coax and the tuner its 1.2 from the tuner on out its still the same coax and antenna

 

[W5LZ]

'555', You're right. But then, that also means that that antenna is radiating something where it isn't supposed to (band it wasn't designed to work on). There will be some losses because of that, how much just depends on how far away from it's design frequency the thing is. Another 'but' is that it can be used, you will have an antenna capable of radiating whatever power gets to it. 'Best' in the world? Nope, but it doesn't have to be the 'best' to be perfectly adequate at times. Which is the whole point, isn't it? Another aspect of it is that since the radio sees something it's happy with it puts out full power. If it sees something it isn't happy with, it certainly won't do that. So, you get the benefit of whatever the difference between full power and whatever that lower power output is. Carried to the extreme, it's the difference between having an antenna and not having one. Which is the whole point again. As long as the antenna being tuned for off design frequency is sort of 'close' to some particular length in relation to wave length (1/4, 1/2, 5/8, 13/42, whatever), it ought to work at least 'fair'. Sure beats no antenna, huh? And all things considered, it probably beats having a ga-jillian other antennas, sort of. Tuners don't 'do' miracles, but they are handy little 'doo-gees' to have around. - 'Doc

 

[KingCobra_CDX882]

It Amazes me..

So many people use a "tuner"

However so few people know how to use it or why to use it.

The reason to use a tuner is if your antenna is not resonate on a particular frequency.
If this is the case then using a tuner will enable ones radio to see a low swr where otherwise a higher swr would be seen by ones radio..
So your radio will be happy and its finals safe....
This will not persay enable your radio to transmit extremely well when the tuner has to "ajust"
what the radio sees for an swr (because in so needing to "ajust" the swr to make radio happy means the antenna is not particularly resonate on that frequency.

So what does that mean
Ok you have room for a single antenna but are trying to get it to work across several frequency bands....but as was said earlier...it is possible to get a coke can to show you radio a desirable swr so that it will transmit at full power and not "worry" about damaging-destroying its finals..

So what really is a "tuner" good for..
is simple

if you are using say a multiband antenna or even a single band antenna
say if it a rather far run from your radio to the antenna
so using a 50 ohm coax-feedline would incur a lot of loss (thereby greatly reducing your antennas ability to talk and recieve at a good distance)
So instead of coax one desides to use say 300 ohm open wire-ladder line (for extreme low loss of signal)..

Now here is where a tuner truely works as it is designed for our radios need to see 50 ohms
So now the tuner will match the feedline 300 ohm and bring it to 50 ohm matching for our radio....now we obtained extreme low loss with open wire feedline and still able to show 50 ohm and low swr to the radio......but because the antenna is extremely resonant on the frequency you are on....and since the radio now sees also the 50 ohms it needs as well as low swr....now everything works great...so nearly all you power goes to radiate on your desired frequency-band..

So in conclusion..
if your antenna is well designed for the frequency you desire and or need to use..
then using a tuner to over come either poor feedline and or unmatched ohms is what most tuners are truely designed for

i bet at least 70% of people using tuners are Not using them Properly

I have a tuner and have had it for years..
I also have never used it..
For my antennas are designed properly to radiate effectively on the frequency's i use
Also my coax-feedlines are in exellent shape

there is another use for a tuner
is a way to use a tuner to help you hear a bit better
to help pull contacts out of the qrm (although i have not needed to use it for that)

anyways
that is my 2 cents

 

[KingCobra_CDX882]

It Amazes me..

So many people use a "tuner"

However so few people know how to use it or why to use it.

The reason to use a tuner is if your antenna is not resonate on a particular frequency.
If this is the case then using a tuner will enable ones radio to see a low swr where otherwise a higher swr would be seen by ones radio..
So your radio will be happy and its finals safe....
This will not persay enable your radio to transmit extremely well when the tuner has to "ajust"
what the radio sees for an swr (because in so needing to "ajust" the swr to make radio happy means the antenna is not particularly resonate on that frequency.

So what does that mean
Ok you have room for a single antenna but are trying to get it to work across several frequency bands....but as was said earlier...it is possible to get a coke can to show you radio a desirable swr so that it will transmit at full power and not "worry" about damaging-destroying its finals..

So what really is a "tuner" good for..
is simple

if you are using say a multiband antenna or even a single band antenna
say if it a rather far run from your radio to the antenna
so using a 50 ohm coax-feedline would incur a lot of loss (thereby greatly reducing your antennas ability to talk and recieve at a good distance)
So instead of coax one desides to use say 300 ohm open wire-ladder line (for extreme low loss of signal)..

Now here is where a tuner truely works as it is designed for our radios need to see 50 ohms
So now the tuner will match the feedline 300 ohm and bring it to 50 ohm matching for our radio....now we obtained extreme low loss with open wire feedline and still able to show 50 ohm and low swr to the radio......but because the antenna is extremely resonant on the frequency you are on....and since the radio now sees also the 50 ohms it needs as well as low swr....now everything works great...so nearly all you power goes to radiate on your desired frequency-band..

So in conclusion..
if your antenna is well designed for the frequency you desire and or need to use..
then using a tuner to over come either poor feedline and or unmatched ohms is what most tuners are truely designed for

i bet at least 70% of people using tuners are Not using them Properly

I have a tuner and have had it for years..
I also have never used it..
For my antennas are designed properly to radiate effectively on the frequency's i use
Also my coax-feedlines are in exellent shape

there is another use for a tuner
is a way to use a tuner to help you hear a bit better
to help pull contacts out of the qrm (although i have not needed to use it for that)

anyways
that is my 2 cents

 

[W5LZ]

KingCobra_CDX882,
I'm sorry, but you're mistaken. The only thing a tuner does is match impedances between whatever is on either side of it. That has nothing to do with resonance.
- 'Doc

 

[KingCobra_CDX882]

i know has nothing to do with resonance
people use it often thinking an atenna not resonating well on a frequency
can be fixed by a tuner
simply because a tuner shows a radio a good swr

 

[W5LZ]

Right, but a tuner can make a non-resonant antenna -usable-, which is sort of the point. While resonance is a nice thing to have, it certainly isn't always the 'best' alternative. If a non-resonant antenna puts a signal where you want it to go, and if using a tuner makes that signal stronger than what it would be otherwise, then a tuner is a pretty handy little 'do-dad' to have. But it isn't a miracle worker, just handy.
- 'Doc