Amateur Radio Stack Exchange
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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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How does lowering the RF Gain help with SNR?

Let's say for sake of example we are in the 40m band. I've read articles and posts about riding the RF gain (or even just simply lowering it). And I can see how it is useful in overload situations. What I don't quite get is how lowering the RF gain…
Paul
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PL-259/SO-239 vs N Type vs BNC which is best connector to use when?

I understand that the: PL-259/SO-239 connector (so-called "UHF connector") isn't great for UHF frequencies, but is very common N type connector is water-proof; and the BNC connector is quick to connect and disconnect From James Eagleson's YouTube…
Amin Shah Gilani
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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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Digital transmission sounds

I'm playing with an RTL-SDR dongle and an LNA, on Linux Mint with GQRX and DSD A lot of frequencies show digital transmissions, which the DSD is not converting. I don't whether it is a format DSD cannot convert, encrypted, or just distorted. Is…
KP4MCG
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Soldering PL-259.. with a torch?

I came across this article about torch soldering PL-259 coax connectors. It seemed like a good idea since the body needs a lot of heat to get solder to flow into the holes. It's a little vague when describing the soldering technique for soldering…
Paul
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How can I calculate current distribution on an end-fed dipole antenna in theory?

I understand that in a half-wave center-fed antenna current distribution has a sinusoidal wave approximately, so the current in the center has max value and it has to become zero at the ends of dipole which are open. But since we change the feed…
M.D
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Are there reasons why a receive-only wire antenna should not be λ/2 in length?

The answers to this question explain why it's difficult to transfer power from a transmitter to an antenna that is λ/2 in length (or a multiple for long wires, or as half a dipole's length). Are there reasons why this length would not work or be…
hotpaw2
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Frequency Modulated Light

I've been doing a bit of work on optical open-air transmission, and have been thinking, any hays that varies the intensity of the light or whatever else would affect the amplitude. Would it be possible to send and receive a frequency modulated…
Skyler 440
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