| Author |
Message |
    
Monster
| | Posted on Thursday, October 10, 2002 - 12:25 am: | 
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Sorry if I posted this under the wrong topic, but...
does an antenna tuner actually bring down the SWR or does it make the transmitter think that the SWR is low? I trimed my antenna (mobile) to the proper length, and have a good metal-to-metal ground, but my SWR reading is still somewhere between 2.5 to 3 (depending on the weather). With a tuner in the signal chain I get a reading of 1.5, personally it sounds too good to be true. |
Taz
| | Posted on Thursday, October 10, 2002 - 3:34 am: |
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It fools it and protects from damage.
What kind of antenna is it?
How long is the coax? |
Marconi
| | Posted on Thursday, October 10, 2002 - 8:37 am: |
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Monster, how did you trim your antenna to the proper lenght? What is the proper length? What kind of tuner are you using and why do you use a tuner? Do you work multiband?
In 11 meters, using resonant antennas, there is no need for a tuner.
From your profile, I note that you run a homebrew mobile. You undoubtedly have something missing in your design. Give us a little idea of what that antenna looks like.
Marconi |
2600
| | Posted on Thursday, October 10, 2002 - 11:10 am: |
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Like Taz says, it fools the transmitter/radio. You will still be losing power, but the unwanted heat now goes into warming up the coax, and NOT overheating your final stage. A tuner won't fix an antenna problem, but it can protect the transmitter from one. An antenna tuner is really meant to either 'broadband' an antenna to cover more frequencies than a direct hookup allows, or to feed an antenna that ISN'T 50 ohms in the first place. Modern solid-state ham radios will 'protect' themeselves by turning down the power into a high SWR. A tuner will make it happy so it delivers full output.
The radios and amplifiers are nearly all designed for a 50-ohm load. There are lots of ways to design wire antennas that show 150, or 300, or 450 ohms when they are tuned. 50-ohm coax is not always the best way to feed one of these. A tuner will 'transform' this impedance mismatch on an exotic antenna.
Using a tuner on a 50-ohm antenna is still a 'band-aid', not a fix.
73 |
Unrulyshaman
| | Posted on Tuesday, December 24, 2002 - 7:39 pm: |
|
A MATCHER FOOLS THE RADIO ,BUT A TUNER ACTUALLY
CHANGES THE CAPACITANCE TO MAKE A GOOD 50 OHM INPUT TO YOUR RADIO!DUH ANY FIRST YEAR ELECTRONICS
STUDENT KNOWS THIS DUH DUMMY |
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