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What Determines How Many Watts an Antenna Can Take?

May 9th 2022, 18:07


Joined: Oct 15th 2021, 15:02
Total Topics: 0
Total Posts: 0
New ham (AG) here with a question. I'm going to be making my first antenna soon and there is something I just don't understand. I see antennas available for sale that are rated for a given number of watts. Sometimes its as simple as a fixed watt amount. At other times it's something more complex like "100 watts FM, 25 watts packet" or some similar duty cycle qualifier. I get that "RF gotta go somewhere" and a certain amount of RF is lost as heat with every transmission. But, what part(s) of antennas are subject to failure at higher wattages?

More to the point, when I design my antenna, how can I be sure from a design and materials perspective that a specific antenna can withstand some number of watts for a given amount of time at whatever duty cycle I anticipate? My antennas are mostly going into my attic, so I *really* don't want to create a fire hazard.
May 11th 2022, 07:57


Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
There are now infrared cameras sold to consumers. Some are phone attachments. These can be used to verify the expected temperature rise of antenna components.

Even better would be to use a professional grade camera used by fire departments. Perhaps they would be willing to come out with their gear to make sure there are no issues in your attic.

Zak W1VT
ARRL Senior Lab Engineer

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