Amateur Radio Stack Exchange
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1500 questions
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What are the implications of pulling LMR400 through EMT conduit with several 90 degree conduit body fittings

In order to route my antenna feedlines out of my house, I have to pass through a wall, into the garage and through another wall. All of this involves four 90 degree turns. I am wondering what the possible issues would be with using 2 inch electrical…
ghendricks
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Long callsigns in WSJT-X?

During the month of May (2018) a lot of Belgian club stations can use callsigns in the format OT70xxx. (The xxx is always 3 letters, for example our club station uses OT70TRA.) In WSJT-X it seems impossible to set this call as 'mycall'; the call…
ON5MF Jurgen
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SSB filtering in the frequency domain?

I'm not sure whether it's more appropriate to ask this question here, or in the dsp.stackexchange. But I'll try here first. There seems to be a lot of information available on the filtering and demodulation of SSB signals in the analog or…
hotpaw2
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Antenna Efficiency

Intuitively, we all understand that an antenna at fractional wavelengths will not radiate well even with perfect impedance matching systems. From what I understand the efficiency of antenna has a few factors: Conduction losses (due to finite…
Skyler 440
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Doppler shift compensation without using predictive modelling

Doppler shift mitigation has been studied extensively in the literature. In my implementations of satellite receivers (using GNU Radio), I use predicted Doppler shift from a software (GPredict) to compensate for Doppler shift. After that, I use a…
Moses Browne Mwakyanjala
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Is there such a thing as a phase modulation voice signal?

Wikipedia indicates that in the digital domain ASK, FSK, and PSK are common. It seems that only AM and FM are used for analog forms of communication. Why don't we use Phase Modulation techniques, and stick mostly to variants of AM and FM?
Adam Davis
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BF-F8HP: "Radio did not respond" when trying to use CHIRP

I'm trying to program my Baofeng bf-f8hp with the chirp software, but as I have to do, "Download From Radio", after I choose the appropriate maker, product and model, all I get is an error message which reads, "An Error has occured: The Radio did…
IX Mendoza
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What is this connector?

It is the size of a BNC but has threads. For an RF output. I need to adapt it to SO-239. ---------------------------------------------- Tip o' The Hat to Glenn and Scott. TNC it is. This cable works great: TNC Male to SO-239 pigtail (eBay)
SDsolar
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Dipole antennas: Will paracord hold up well enough in the sun? Is there a better alternative?

Tower is up and pre-stretched multi-strand 14 Ga wires are cut & terminated for a multiband fan-style dipole antenna system. Location is the desert southwest of the USA. Stringing up parts of it are going to be a challenge due to topography, and it…
SDsolar
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RF signal level when the antenna is disconnected

This is question a3a1-1 from the set of practice questions in the "amateur radio Exam Secrets" book: An antenna is connected by a short feeder to the input to a radio receiver. Everything is correctly matched to 50Ω and a sensitive, high impedance…
Pablo Fernandez
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How can I calculate the 1/4-wave monopole impedance dependence on groundplane angle?

I watched this video of a very nice explanation of a simple dipole and 1/4-wave monopole. In that video they show how you can impedance match the 1/4-wave monopole by bending the 4 (virtual ground plane) pins downwards at an angle, $\theta$, from…
not2qubit
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Is hiding your voice on phone legal?

Lets say I use a computer to change my voices pitch, or use computer generated voices to hit a repeater. Is this allowed, or does it have to be my natural voice coming in on phone transmissions? I am in the United States of America.
Skyler 440
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Relations between bit rate, frequency deviation and channel filter bandwidth

I just started using a couple of low power radio modules in my project (HopeRF RFM69HCW). I made them work; they successfully transmit messages in a limited range (5-10 meters). Now I would like to improve that range (with a minimal message…
noearchimede
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Coax cable as antenna for 5 watt handy

For a normal 5 watt handy working in VHF or UHF freq with 50 ohm antenna , is it possible to use a same length coax cable instead of a stub antenna, so as to work like a crude antenna. Will this only result in extra capacitance/ VSWR damaging the…
user132257
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Slot antenna for 2 meter mobile

My primary vehicle is a Smart car, with a roof that's a piece of plastic(100% moon roof). Not the most awesome of cars to use for grounds. I'm building a bumper mounted antenna tower, EMT with some square tube. Earlier today I stumbled across an…
Omagasohe
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