New answers tagged antenna
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Is lightning protection necessary for a mobile setup?
I'm an exclusively SOTA and POTA activator. I don't have a home station due to urban noise.
The most important thing is to avoid putting an antenna when there is lightening risk or near electric power ...
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DIY 40m Antenna tuning: RLC and SWR
Is the perfect antenna going to be (50+0j) Ω?
That will be the perfectly matched antenna, with the minimum feedline loss. It's not necessarily the perfect antenna. A dummy load is 50+j0 too, and any ...
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DIY 40m Antenna tuning: RLC and SWR
@lornop, there's a lot to @Ryuji AB1WX answer, and certainly all valid and worth understanding, but just in case some of it is a bit beyond your current understanding, I'll give you a different take; ...
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Is it possible to make a shield that blocks time-varying electric fields, but not time-varying magnetic fields?
If we talk about low-frequency time-varying fields from Hz to kHz and current measurement then often we can see electrostatic shields around magnetic coils. This electrostatic shields, connected to ...
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Why do ham radio operators refer to current flow on the outside of coax as common mode current?
Some very dismissive answers here of a very good question. A similar question was asked in the EE SE, where i believe it was answered better:
https://electronics.stackexchange.com/questions/74661/are-...
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DIY 40m Antenna tuning: RLC and SWR
Excellent that you're using a NanoVNA and measuring complex impedance instead of relying solely on SWR. That's the bare minimum standard for modern antenna discussions. SWR (Standing Wave Ratio) is ...
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What causes this "Wedge" in weather Doppler radar imagery?
The National Weather Service radar at Taunton, Massachusetts (KBOX) is part of the national NEXRAD / WSR-88D network: an S-band Weather Surveillance Doppler radar built to watch storms continuously. ...
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What causes this "Wedge" in weather Doppler radar imagery?
What causes this? I can imagine it being close-range obstructions, or something with the dish passing over a seam in its mechanical assembly, or something to do with signal processing. Is this a ...
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Is it possible to make a shield that blocks time-varying electric fields, but not time-varying magnetic fields?
Sorry to comment on an old post but I believe the accepted answer might not be completely correct (feel free to fill in gaps in my understanding if I got this wrong). The eddy currents which cancel a ...
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What causes this "Wedge" in weather Doppler radar imagery?
An enhanced image from OP's posted image
That was yesterday. Today kept my eye on this station to see if the "wedge" still existed, in the same direction. It seems to be unchanged in this ...
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Current flow in a coaxial cable
If there is no current on the outside of the coax, then it is indeed true that the current in the center conductor will be 180 deg out-of-phase with that on the inside of the coax shield. Remember, ...
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Alpha Delta DX-B Antenna Installation
OK SamR, it's very common for folks to mix up DC grounding for static and lightning mitigation, and RF grounding. I think most experienced people will say if you want a DC ground, you can, and should ...
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