I have a 25w radio running through a ~4.5db gain antenna. If I use a 4W HT indoors, I can hear a loud buzzing noise emmanating from my computer speakers.

If I used the 25w mobile with the 4.5db gain antenna close (within 2-3ft) to any unshielded electronics, could they get damaged? Cliche, but the landlord says no antennas on the roof.

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    $\begingroup$ in the early 2000's I used an indoor loop that pretty much spanned the size of my bedroom, with a 4W CB radio transceiver (i.e. ~ 27MHz), and when I hit transmit, my back then computer, some AMD K6-II 600MHz or whatever, reset and did wild things... That computer was pretty much inside the antenna, though. $\endgroup$ – user1847129 Jan 23 '19 at 21:31

Possible, but very unlikely unless you have some extremely sensitive electronics. If you did you'd know it, because cell phones and WiFi would also be hazards.

The buzzing you hear is the RF current being picked up by the speaker wiring, then rectified and amplified by the speaker's electronics. It's no more damaging than plugging the audio input of the speakers into a recording of a similar noise.

To put your mind at ease, consider all the other RF radiators you likely have lying around: your cell phone, WiFi in your laptop, etc. These are probably somewhat less power, around 1W, but the difference isn't huge. Power density falls off with the square of distance, so if your HT has 25 times the power, it's similar to a 1W device at $1/\sqrt{25} = 1/5$th the distance.

So say you are worried your HT might damage something five feet away, ask yourself: would you worry about a cell phone damaging the same thing at one foot away? Probably not.

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  • $\begingroup$ Interesting. Thanks for the practical and theoretical perspective. Ironically, the cable length to my speakers is approx quarter wave of 2m as well. $\endgroup$ – Saustin Jan 24 '19 at 1:16

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