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1500 questions
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3 answers

Colocated three orthogonal wire loops for lightning detection network

I'm considering building multi-turn wire loop receive antennas for a blitzortung.org lightning detection receiver. It has three separate channels for H-field antennas, operating simultaneously. Typically, only two orthogonal loops in vertical…
Xpector
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What's this maybe-morse-code "CQ CQ GE EDEN" and "DD" in Le Eden de la Grisaia?

The ending song of an anime television series called Le Eden de la Grisaia here has a light flashing. I suspect it may be Morse Code. By watching the video a little more slowly than usual (frame by frame), it's easy to see that dit is 2 frames dah…
pj-yn9aq
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Satelite dish modified for Wi-Fi (Signal Elevation Question)

I am doing a project where I will be re-purposing an old TV satellite dish as a directional Wi-Fi antenna. The dish is circular in shape, not oval. The dish has an arm coming from the bottom that makes a 90 degree angle with the dish. I will be…
Jake Psimos
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Is using a DDS chip directly a viable way to transmit 2FSK and PSK on HF?

I'm thinking of building an HF transmitter for data (AX.25 or PSK31). Rather than using an IF stage, I'm thinking of generating the RF frequencies (or phases) directly with a Direct Digital Synthesis chip. The chip I'm thinking of is the Analog…
watkipet
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What are the consequences of poor station grounding?

What can happen if I don't properly ground my equipment?
JC Hulce
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2 answers

SDRPlay RSP1 and broadcast band (AM) interference

I heard the SDRPlay RSP2 has an AM notch filter, but I don't want to spend that much money. How is the RSP1 for broadcast band interference? Will I need a preselector? I already have an MFJ-1020c but am hoping to sell it to offset some of the cost…
K8KV
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Suggestions for HF antenna for occasional use on my sailboat

I have had a license since I was a kid, but have not touched anything ham radio related in years. I have been thinking about diving back in and combining it with my sailing. I'm looking for thoughts on an HF antenna that I can easily deploy when…
Jim Archer
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1 answer

Pirate Radio vs Ham Radio

I've recently came across the terms "Pirate Radio" and in the URL of this page, "Ham Radio". What is the difference between these terms? And what is the difference between the transmission of a Pirate Radio and a Ham Radio.
anonymous
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What is the point of high gain antenna with respect to the maximum EIRP

OFCOM states that the maximum EIRP within the UK for 2.4 GHz is 100mW. Simply put, what is the point in being able to buy 2.4 GHz high gain antennas which can say do 24dBi, which already puts the output power at 256mW? Is this a case of OFCOM…
R4D4
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Building a crystal radio with my brother. How does this circuit work?

I'll be visiting home soon after school lets out, and I want to build an AM crystal radio with my little brother. This is the design we'll use: http://crystalradio.net/beginners/ I'll be doing my best to explain to him how this works. I understand…
BitPusher16
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Grounding a dipole

How do you properly ground a dipole (RX only for VHF scanning) to protect it against ESD/lightning? In my set up i'm putting a dipole on my roof. I've connected the two dipole elements together with a 100k resistor, and have a balun and amplifier…
Projectile Fish
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Why is coax loss logarithmic?

With DC hookup wire, losses are directly proportional to length. If the resistance of 100m of wire is 10 ohms then the resistance of 200m of wire will be 20 ohms. But we measure coax loss in decibels per given length. For example, this chart lists…
natevw - AF7TB
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What kind of losses do you get from an LC network matching the antenna's impedance?

If you have a transmitter that is perfectly on your frequency but you have an antenna with some impedance what types of losses, and of what magnitude, will you expect from a tuner in between your transmitter and antenna? For example lets say your…
Joshua Katz
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DAB antenna in roof space

We are setting out our roof-space as an attic, and after decorating, there will be a triangular void under the house ridge, which will be about 36" wide, and 18" high. I can easily fit a standard folded dipole loop antenna for VHF FM, but the DAB…
DaveAt168
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FM squelch SDR algorithm?

What signal characteristics in an SDR receiver signal path should be evaluated or computed to determine whether the audio output should be squelched or not? What sort of computed result should be compared against a scalar squelch "knob" setting? I…
hotpaw2
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