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1500 questions
4
votes
3 answers
Do I need a license to operate as a ham in Haiti?
I am currently thinking about joining the shortwave radio community, and know that if I was going to operate one in the U.S., I would need a license to operate in a certain range. But I am not living in the United States, I am living in the island…
Mr.Zeus
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4
votes
3 answers
Is RF current always confined to the inner diameter of a braided outer conductor of coaxial cable?
Prompted by a previous question found at Using a balun with a resonant dipole -- an answer there included the following text:
"For transmission lines (twin-lead or coax) to not radiate, each conductor must carry equal and opposite currents. It's…
Richard Fry
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4
votes
1 answer
How Does the Performance of Elevated Radials Differ from That of Buried Radials?
NEC4.2 provides some information about this topic that may be of interest to some readers.
Richard Fry
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4
votes
2 answers
Use noise figure and gain to calculate weakest signal radio can receive?
An FM radio receiver, using a 1 kHz tone at 3 kHz deviation has a 12 dB SINAD (Signal To Noise and Distortion) of -116 dBm.
I would like to increase the 12 dB SINAD sensitivity of the receiver to at least -121 dBm to increase the weak signal…
Skyler 440
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4
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1 answer
How Does Earth Conductivity Affect the "Takeoff Angle" of a Vertical Monopole?
NEC4.2 gives some insight into this ...
Richard Fry
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4
votes
3 answers
Why are carrier waves necessary?
I am studying for the technician exam and I have come across the section on carrier waves, basebands, and various kinds of modulation.
It makes sense to me that you create a signal by combining the baseband, which carries data, with the carrier…
user11031
4
votes
2 answers
What type of signal is this?
I received this signal around 7 MHz. I've checked all over the "Signal Identification Wiki", but cannot find anything similar to this. I'm pretty sure this is some simple FSK, but that is the exact type?
The signal is at around 2200Hz (in audio…
Risahas
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4
votes
3 answers
Suggestions for mounting a mini-whip as high as possible
I've ordered two mini whip antennas from Ebay (Russia) for HF and MW. As power lines cross my city property in a L shape - the only way to get away from them is to go up. So I'm hoping that going 5-20 feet above my roof line will reduce the…
Aaron Kreider
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4
votes
3 answers
SDR set up that will TX & RX on CB, UHF and VHF
I would like to use SDR to receive and transmit on CB, UHF and VHF. Is this possible and if so what type of equipment will I need (antennae, dongle etc)? I currently have both UHF/VHF and CB but atm have separate antennae for each rig. Reading about…
welfare
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4
votes
1 answer
Why does P25 occasionally break through tone squelch on my analog HTs?
When listening to our local repeater, which is now a combined P25/analog machine, every once in a while my squelch opens to a blast of digital noise. I've noticed this problem with at least two different Baofeng radios (a UV-3R+ and a UV-82). I have…
MoTLD
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4
votes
1 answer
Antenna, input and ground bonding
I'm new to this and am in need of guidance. I am mounting a multi-band antenna on a 50 foot tall 1 1/4" galvanized mast. I plan to drive a ground rod at the base of the antenna and bond the mast to it. I also plan to ground the RG-8/U at the top…
user10650
4
votes
2 answers
Can you create a radio beam with a Faraday cage?
Imagine we have an isotropic antenna at the origin emitting a steady sine wave at frequency $f$. Encompassing the antenna is a sphere of radius $r$ made of a fine copper mesh (with holes $\ll\frac\lambda{10}$, making it a Faraday cage).
From this…
Jerald Thomas
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4
votes
1 answer
Can an American licensee operate in Portugal during a visit?
I have an American Amateur Extra Class licence (AC1DM) and I'm going to Portugal for a few days. Can I operate there with my licence? I'm not an American citizen.
Pablo Fernandez
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4
votes
1 answer
Do people really do GMRS liscenses
Sometimes on my Chinese uhf/vhf amateur transceiver, which goes all the way to 520 megahertz, i listen to GMRS/FRS/MURS frequencies. I always hear little kids messing around in the neighborhood on GMRS. Does the FCC really care about this? And what…
Skyler 440
- 7,600
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- 49
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4
votes
3 answers
Radials on a vertical, spread out evenly or not?
To have a groundmounted quarter wave vertical with a decent efficiency you need at least 16 radials.
So normally you would spread them out on the ground evenly around the base. This would give an angle of 360/16 = 22,5 degrees between two…
ON5MF Jurgen
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