SWR and Power Output on HF

[DewAddict]

Hi all,

So my HF antenna runs between 1.5:1 and 2:1 SWR on most of the bands I operate without a tuner. As expected I have some reflected power upon transmit. Help me understand the benefit of using the internal tuner to bring the SWR down to 1:1 which it will easily do, rather than just rolling with it the way it is? If I bring it down to 1:1 using the internal tuner, other than "tricking" the radio into thinking it's a perfect match, does that lower the reflected wattage out at the antenna? I was always under the impression the antenna is what it is without a tuner, meaning a tuner won't make your antenna "better" at radiating the lost power. It can not get any better than what the SWR is without a tuner so although the radio thinks it's better, it doesn't really do anything as far as radiating more of the power that is reflected/lost at the original 2:1 SWR.

Hopefully my thoughts have made it to the forum in a sensible way. Thanks for the time.

 

[AK9R]

I was always under the impression the antenna is what it is without a tuner, meaning a tuner won't make your antenna "better" at radiating the lost power.

That's generally a correct statement.

The best place for an antenna matching unit, aka "tuner", is at the feedpoint of the antenna. That way, the radio and the feedline see a nearly 1:1 match and there's little or no reflected power in the coax. Putting the "tuner" at the radio, or in the radio, only makes the radio happy. But, the coax is still dealing with reflected power from the antenna.

 

[littona]

...and making the radio happy helps keep your investment working longer, by keeping that reflected power from getting to the amplifier chips/tubes in the transceiver.

 

[jwt873]

Most modern radios have protective circuits in the output that reduce transmitter power when there is SWR present. As the SWR goes up, the output power goes down.

Using your internal tuner will prevent this power reduction from occurring. Although the feature is very noticeable at high SWR. I doubt if there is much power reduction (if any) at 2:1 or less.

 

[bharvey2]

As mentioned above, a tuner at the radio serves the radio but doesn't do much for the antenna system. 1.5 to 2:1 isn't much to be concerned about but heck, if you have a built in tuner, why not? It could have the added benefit of making you feel better too.

 

[DewAddict]

Thanks everyone for the responses. I'll go ahead and bring it down using the internal tuner and call it a day. Excellent info provided by all.