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I live in a residential area and I want to test and design an antenna in my garage. I plan on using my signal generator as the power supply and a RTL - RDS dongle connected to my computer as the receiver. The signal generator spans from 0 to 60 MHz. The amplitude has a range of 5 to 20 volts. My question is will my em waves interfere with my neighbors? If so what can I do to test designs and not affect the neighborhood?

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  • \$\begingroup\$ Would Electrical Engineering be a better home for this question? \$\endgroup\$ – Qmechanic Oct 23 '18 at 2:40
  • \$\begingroup\$ I’ll move it over there. \$\endgroup\$ – Lambda Oct 23 '18 at 2:42
  • \$\begingroup\$ What sort of tests? The garage will interfere with the antenna - at those frequencies it needs to be outdoors and in the clear, as objects in close proximity can have a significant affect on characteristics. \$\endgroup\$ – Chu Oct 23 '18 at 6:17
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Consider buying an antenna analyzer. This is exactly their use case.

An antenna analyzer is a device that injects a low power signal into an antenna and measures complex impedance. This is done over a range of frequencies.

As an example, mine cost a few hundred US dollars and works up to 500MHz. There are many brands at different price points, each using different methods for accomplishing the task so it is worth reading reviews to understand what makes them special. Mine was a little more expensive, partially because of the extended frequency range and partially because it is capable of determining the sign of the complex frequency.

Regarding voltage level, asked in an above comment, that really depends on the antenna's radiation resistance. The parameter of interest is radiated power (v^2/R). I do not know what the FCC limit is, but it is likely below 0.05 watts, possibly far below. If R is 50 ohms (reasonable for a quarter wave dipole, but very low for a folded dipole) then max V is under 1 volt.

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  • \$\begingroup\$ I was hoping someone could move it to a comment. It does not even try to address the question being asked and is likely, I assumed, quite useless, even if fully fleshed out. But maybe folks had not heard about this specialized equipment; not particularly expensive and makes antenna experiments much easier. \$\endgroup\$ – Chris K8NVH Oct 23 '18 at 9:27
  • \$\begingroup\$ You can also ask around (Amateur Radio community) to see if anybody has a Vector Network Analyzer (VNA) which the antenna analyzer is basically a subset of. Getting one with an s-parameter test set makes it even easier, and you can sometimes find good deals on them (yes there is an extra zero on that price tag, though). HP made them by the boatload and the 80s technology is pretty robust. \$\endgroup\$ – isdi Oct 23 '18 at 11:48
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Aside from the being technically illegal to be radiating like that (unless you're below the CFR47 Part 15 unintentional radiators limit, at 5V highly unlikely unless your antenna is really inefficient at those frequencies):

Off the top of my head, most people would notice AM radio, CB some of the (really) old RC control stuff. You'll be hitting several Amateur Radio bands- they may find you before the FCC van does (if you're in the USA) as well as a bunch of international radio bands, amongst other (government) services for long-range communications and radiolocation services. FCC maintains a table for usage even if not detailed, you have to go to the CFR sections to pull those details out.

Priority 1 is to reduce your signal strength output- absolutely no reason to be transmitting high field strengths it's all linear.

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  • \$\begingroup\$ What voltage would you recommend? \$\endgroup\$ – Lambda Oct 23 '18 at 4:07

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