# Tag Info

3

I'll add that a tuner is used for tuning, and tuning, for a single or small set of frequencies is often done at the antenna, usually by adding or adjusting a loading coil or adding a capacitive top-load or hat (etc.), usually done during antenna design, construction, or deployment. However a tuner is used for a wider range of tunings, thus has additional ...

3

To make a long story short, if you are using 50 ohm coax with a 50 ohm radio, putting the tuner at the antenna is higher efficiency because it reduces losses in the coax caused by high SWR. However, putting the tuner at the antenna has some huge disadvantages. It has to be weatherized. It is more prone to damage from lightning. It has to be remotely ...

-4

The conditions on a transmission line in terms of the line impedance depend on the characteristic impedance of the line and on the boundary conditions, which are in this case a transmitter at one end and an antenna at the other. In other words the source (radio + matcher) and load (antenna) both have an effect on what is happening everywhere on the line. As ...

7

There are a lot of topics in this question, so let's take them one at a time. I figure the transmitter has a 50-ohm pure resistive output Not necessarily. You're probably arriving at this conclusion based on the maximum power transfer theorem. Which of these circuits delivers more power to the load resistor? simulate this circuit – Schematic created ...

1

If you do not use the tuner, you are getting some power (another answer here says around 4%) reflected back into the final stage of the power amplifier (PA) of the radio. This will cause the final transistor(s) to heat up, and the cooling fan will be used to remove the heat. If you do use the tuner, you move the mismatch from the PA to the tuner circuitry, ...

1

For transmit, compared to a perfect SWR of 1:1, an SWR of 1.5:1 will give about 4 % loss of power radiated by the antenna due to reflections at the antenna / feed line junction. All other things equal, this will result in about 0.2 dB drop in signal strength for a remote station receiving your transmissions. Similarly, for your receive , compared to a ...

2

If it is convenient to reduce the swr by fixing the antenna, that would be a more effective solution. But, as you say, 1.5 is not that bad, and likely you would like to continue using the antenna in the phone region anyway. So is it better to run it at 1.5 or engage the tuner? It is probably easier on the radio to use the tuner. The disadvantage of the ...

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