niels nielsen
  • Member for 4 years, 2 months
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  • corvallis, oregon, united states
Use (TV?) Log-Periodic antenna for VHF
5 votes

Those antennas are held together with aluminum pop rivets which are easily drilled out. In less than an hour you can completely disassemble a TV antenna like that and salvage the main mast, all the ...

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can the adhesive used in thru-glass antenna couplers be replaced?
4 votes

Yes, there is. The protective tape that you peel off the mount before pressing it onto the window glass bears the emblem "3M", identifying it as a product of the 3M adhesives group. A web ...

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What does the spark-gap do in a spark-gap transmitter?
4 votes

the spark gap's purpose is to very suddenly change the current in the LC circuit to which the antenna is, in fact, directly connected. the sudden change produces a very strong inductive kick in that ...

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What comes first, Voltage or Current?
3 votes

In dynamic systems modeling, this issues is known as causality. In the case of inductances, one instantaneously asserts a voltage across the inductor and the inductive system then returns a time-...

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What causes an AF amplifier to make popping sounds in a superheterodyne receiver?
3 votes

Try powering the LM386 temporarily off a battery. if the popping stops, then the cause is a surge being conducted into the 386 from the supply that feeds the rest of your circuit. Normally, you would ...

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Determining one exact antenna length for a whole band (e.g. FM/AM broadcast, Bluetooth and others)
3 votes

FM antennas (the sort that come with your receiver) are trimmed for best performance in the middle of the FM band. Because that band is not very wide, and the signals they receive are generally not ...

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Help setting up my uv-5r radio
2 votes

There is a very neat programming aid called CHIRP which can be used on the UV-5R and similar radios from B-Tech/Baofeng. It allows you to type up a spreadsheet on your computer with all the pertinent ...

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what is main reason for formation of side lobes in directional antennas?
1 votes

Here is an easy way to visualize what's going on with those pesky side lobes. We take the case of a centerfed resonant dipole with a wire a little longer than the dipole mounted behind it by some ...

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Practical limits to maintaining coherence in an HF channel
1 votes

Any transmissive data channel will hit a lower power limit for readability when the signal no longer exceeds the noise floor of the transmission mode. This is another way of saying that the minimum-...

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How to transmit computer audio to a wireless microphone receiver?
0 votes

I have indeed done this simply by disassembling the wireless microphone and wiring in an auxiliary input jack in place of the mic element along with an attenuator so the AUX IN signal from the ...

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What is the radiation pattern of an ~60 foot end fed wire antenna used for 40 meters?
0 votes

See if you can make a connection to a rainwater downspout near your window. downspouts and gutters can sometimes make decent "invisible" antennas of the end-fed random wire type; as such you'll need ...

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