Antenna tuners ?.....

[Oatmeal]

Hey guys, I dont no much about these tuners, so like to ask you all a few questions..

Once you have your antenna adjusted to the lowest swr u can get it...

Do these tuners, like fine tune the swr or brings it down lower, are these tuners just to fool the swr meter ?....

Do they actually work ?...where does the swr go to ?...

And once the swr is down is it ok to run those amps safely on the antenna ?...

By the way, this would be to talk on parts of the 10m band and for 11m band usage, for now...

 

[W5LZ]

"Do these tuners, like fine tune the swr or brings it down lower, are these tuners just to fool the swr meter ?...."
All that a tuner does is convert one impedance to another. It's a transformer, just like the transformer that changes 120vac to 12vac which is then rectified to DC. So, it changes whatever the impedance of the antenna system to the 50 ohms that your transmitter wants to see. It doesn't change the antenna system at all (feed line and antenna). If you want to call that 'fooling the meter', then that's what's happening.

"Do they actually work ?...where does the swr go to ?..."
A. Yes, they work. They make the antenna system acceptable to the transmitter so that it will put out full power.
B. There isn't any SWR to 'go' anywhere. It's still there. SWR isn't a 'discrete' thingy at all, it's only a ratio of forward to reverse power. If you put an SWR meter behind that tuner it will show exactly what it would see if that tuner wasn't there. If you want that SWR to 'go' somewhere then tune the antenna. Reread (A) gain.

"And once the swr is down is it ok to run those amps safely on the antenna ?..."
Probably, if the antenna system is capable of handling the power that is being fed to it. The amplifier will 'see' a good impedance match (low SWR). The 'catch' with that is that since the SWR/impedance mismatch is still there in the antenna system, if that mismatch is bad enough then there may be damage to the system (feed line mainly). The way around that is to put that tuner at the feed point of the antenna so that the feed line isn't in the 'mix'.
Tuners are not miracle workers. They can change an unacceptable impedance match to an acceptable one. That's all they do. There are better ways of doing it, but sometimes those 'better ways' aren't possible. That's when a tuner comes in real handy.
- 'Doc

 

[Oatmeal]

10-4, what brought this to my attention was a guy was talking about having a 3 swr, and he used a tuner to get it down, so he could use his amp on it....

I dont remember how much the tuner got it down to, but I thought Id try to learn some about how they work ect...


What do you guys think about the automatic antenna tuners ?.....

Or do you guys like the manual tuners ?..

 

[W5LZ]

I use both, a manual tuner and an autotuner built into a radio. Just depends on which will handle what I'm trying to use as an antenna. I'd love to have an external autotuner but I'm too cheap. I would want a huge one, capable of handling a lot of power. Those things are just not cheap at all. The manual tuner I have is a quite old one, been around for a long time. So far, it's been able to handle almost everything I've ever connected to it. for that kind of capability I don't mind twiddling a knob or two, or three. Because transforming/changing impedances results in high voltages a really capable tuner is going to be large (because of the size of the capacitors mainly). Size isn't really a good way of comparing tuners, but the small ones just aren't capable of withstanding some of the voltages that happen. (A kilowatt sized tuner the size of a match box just isn't very realistic at all. That's an exaggeration, but not much.)
Are they worth having? Well, they are to me. I like playing with antennas, some really odd ones at times, and they certainly do make that possible. Should you have one? How would I know? Making the antenna resonant and impedance matched is the better way of doing it, if possible. If not, then...
- 'Doc

 

[Wire Dawg]

I'm contemplating a tuner, but the reports I've read so far have convinced me that the greater benefit is for operators that wish to use one antenna for multiple bands, have radios with low tolerance for impedance mismatch or maybe have restrictions to alter their antennas. I'm convinced that radios/ amps that find the near-perfect 50 ohms load of a tuner will suffer less/ maybe last longer. But as far as improving quality of a signal, I do not perceive any advantage of using the gadget over a good o'l manual tuning of the antenna. If your radio tolerate some mismatch, and you can lower/ raise your antenna for tuning, then the purchase (IMO) will be a waste. OTOH, if you want to TX on 10, 11, 12 meters or other, a tuner may allow it without having to use two antennas.

 

[Mudfoot]

That's true..

I operated for many years without a transmatch. I had plenty of land at my last QTH that allowed me to utilize monoband antennas. Even then, I only operated on a few bands though.

Now, since I have less real estate, I still have resonate monobands for 6, 10, 40 and 80. I have a vertical and fan dipole that I now use a tuner to tidy up with for use on the WARC bands.

My dad has been licensed since the 30's and has never owned a transmatch. If you have the space, the wherewithal, and must utilize every available band and spectrum allowed, then establish a big ass antenna farm and tune them to your hearts content, wish I could.

It's admirable to avoid using a transmatch, but more enjoyable and less troublesome if you do.