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What are the radiation limits in U.S. HF bands in terms, not in terms of uV/M, but in dBm or uV levels transmitted though an HF dipole antenna? I assume that if the antenna is connected to a receiver (or transceiver in receive mode), not an intentional HF transmitter, that the RF radiation might be considered unintentional (but IANAL).

Many modern SDR receivers and receiver kits are not much different from a high performance digital computer, with lots of stuff (clock signals, GHz microprocessors, FPGAs, network, video and IO drivers, DC-DC converters, and etc.) that can generate a vast range of digital broadband noise (edge rates, ground bounce, PCB trace crosstalk, and etc.) some of which is right across the HF bands.

If I measure some broadband digital noise in the very near vicinity of my receiver's antenna connector at somewhere in the neighborhood of up to 10 uV (which corresponds to Tx at around -40 dBm when I connect my 50 Ohm coax and an HF antenna to the receiver), how many uV/M might my HF antenna be radiating, and how does that level correspond to U.S. FCC legal limits?

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Unintentional radiation is literally just that...it is RF emissions from a device that are not intended to radiate. A receiver can be considered an unintentional radiator if it's a super-het design as you do have a local oscillator. But that signal usually doesn't make it out to the antenna, it won't pass through the mixer networks. The same goes for SDRs.

IF you want to know what signal is making it out of the antenna...then you need to look at what's actually making it to the antenna. Just because you measure some noise in the vicinity of the connector, it doesn't mean it's making it to the antenna.

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    $\begingroup$ I mean no offense, but I downvoted your post because it doesn't answer the question. Also unintentional radiators might not radiate much compared to intentional radiators, aka transmitters, but they do radiate, as anyone who has compared the RF noise level in a city to that of a rural or wilderness area knows. $\endgroup$
    – rclocher3
    Jun 21 at 14:59

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