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1500 questions
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How far from earth do FCC regulations apply?

So, I know people in the space station need a HAM radio license for operation. How Far exactly from earth do you have to be to transmit any RF wave you want without a license?
Skyler 440
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What frequencies am I not allowed to use north of line A in the USA?

What frequencies can I not use if I live north of line A in the USA?
Timtech
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How long can a transceiver be unused before I have to use a variac?

I have an old TenTec Argosy II that hasn’t been powered up for 20 years. How long can electronics go unpowered before I have to worry about the electrolytic needed a slow power up with a Variac?
kd4ttc
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How to measure wire for antenna leg | 40m inverted V

I am building the antenna for the first time and I have choosen to start with 40m inverted-v. I am almost done with the center insulator made of PVC piping elements, three eye hooks and SO 239 connector at the bottom. Now I am getting ready to…
Bogdan YU2DBC
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Loop antenna layout and radiation?

I've got, for the near term, limited resources to put up an HF antenna at my home. One of the options I can manage without excessive cost is a loop, which would enclose the house. I need to transmit on 80m, and likely up to 20m (I understand loops…
Zeiss Ikon
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Can I have a signal generator on while it's not connected?

The unit in question is an Elecraft XG3 test signal generator. It puts out anywhere from -107 dBm to 0 dBm. Is it safe to have these signal generators on and transmitting while not connected to anything, or should they always be connected to a 50…
Paul
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Why do receiver sensitivities vary so much with frequency?

I was looking for a 2.4 GHz WiFi antenna to catch a weak free WiFi signal, and amplify it so I can use it. I found Ruckus Metroflex NG, which can receive signals down to -108 dBm. Which is amazingly weak; however, while searching for such an…
Alex
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Does a loop antenna have less susceptibility to atmospheric noise than an open ended antenna?

I always get the feeling that an antenna which has a loop for the driven element such as a folded dipole or quad will pick up less static or 'high impedance' noise than an antenna that has free ends such as a dipole or long wire. Noting that…
Andrew
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Determining Impedance With An Antenna Analyzer

I need some help interpreting some information from my antenna analyzer (RigExpert AA-35). I want to use the information to impedance match my AM receiving antenna system to AM radios. No transmitting, just receiving. The data was captured at the…
B. Varner
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How to convert a Morse Code Message/QSO from Mp3 file into text?

I tried to use both: Cwget CW decoder But neither one worked. Can you recommend a tool or an alternative approach to decode a Morse message saved as an Mp3 file?
MedAli
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How can I be sure I'm actually hitting the repeater?

I'm just starting to use 2m and 70cm bands, which normally use repeaters to extend range beyond a mile or two (limited mostly by line of sight, as I understand it). When I'm at home, however, I'm not at all sure I have line of sight to any of the…
Zeiss Ikon
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Substitute for 455 kHz Ceramic filters in new designs

I am looking to design a dual conversion FM receiver/power meter for t-hunting similar to the MK4 sniffer using 10.5 MHz and 455 kHz IF. In my research it appears that manufactures have stopped making 455 kHz ceramic filters. I am in the U.S.A.…
Jason R. Moore
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Is compression "encryption" under FCC regs?

I read this question about digital signatures and FCC prohibitions on "obscuring" messages in amateur transmissions, and it cause me to think of something: the difference between encryption and compression is small. If I send a file in compressed…
Zeiss Ikon
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What are these antennas used for?

I noticed this antenna park in Heidmoosstrasse, Switzerland. What is it used for?
Loreno Heer
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Unidentified signals on FT8 frequencies

When I work in FT8 mode I often see signals like these: I couldn't identify these signals using SigiWiki nor managed I to decode them using WSJT-X. Though these signals seem to use 15 second frames. They don't seem to be a noise created by stations…
Aleksander Alekseev - R2AUK
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