Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

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1500 questions
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1 answer

How is Data Whitening done?

Is it safe to define that Data Whitening is always X-ORing a payload with a pheudorandom sequence known to both receiver and transmitter? In more detail, lets assume the following case. I have the exact pseudorandom string that is used for Data…
Denis
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2 answers

How can Ground Penetrating Radar work?

I was reading about GPR devices recently. Considering the operation frequency of these devices, how they can go that deep (up to 50 feet)? Normally you would only expect a Hz to KHz range signal to go that deep into the ground.
Samk80
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How strictly is "the end of each communication" defined for the purpose of station identification?

I often hear people say brief statements or sentences after giving their callsign for the final time. Examples that I have heard on the air are: "[callsign] clear" "[callsign] listening" "[callsign] testing" "[callsign] back to the net" I've also…
Nat Mote
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How to obtain raw data for Global Real Time foF2 Map

Note!!!!: I am not looking for help with how make a map using Google Maps API (that part is done). I need help with finding data. I am building a shortwave radio/HF listening log book online, and it uses Google Maps for the plotting of receiving and…
cj5
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4 answers

TV strong station has no signal when coax is connected

Right, not directly ham radio related, but this puzzles my ham brain. I have several TVs connected to a distribution amp connected to an outside antenna. All but one work fine, and the one won't pull in the strong stations, but does fine with the…
Duston
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How is it possible for an HF signal to go around the world when part of it must be in sunlight?

I believe most of us know about the ionosphere, and skywave propagation, but I'm kind of tripping up on the D-layer. If the ionospheric D-layer absorbs HF signals (40 meters, for example) during the day, how does my signal at night reach another…
Noji
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How can I sound-proof my generator?

Looking for advice to semi-soundproof my extremely noisy gas generator, which kept everybody edgy on Field Day. It's a real powerhouse, but the cost of that power is my hearing. I'm looking to buy or homebrew something lightweight that I can use to…
Noji
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3 answers

computer control for Yaesu FT-450

I just acquired a Yaesu FT-450 and am interested in what it can do when connected to my PC. I see that there is programming software available with which one can load information into the 450's memory from a spreadsheet-like file, which would be…
niels nielsen
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2 answers

How to adapt commercial VHF yagi for 2 meter amateur use?

I recently acquired a Decibel 3-element VHF Yagi that was formerly in commercial service. I connected my MFJ-259B antenna analyzer to the antenna and found its minimum SWR at 155 MHz. I have not measured the boom length or the element lengths. I'm…
Aurelia Peters
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How to build a balun transformer for 2m RX with low insertion loss

I'm looking into ways to match a 137MHz RX dipole antenna to an unbalanced coax + amplifier. I know there are several types of baluns which can be categorized under magnetic baluns (where there are separate primary and secondary windings) and…
Felix S
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3 answers

How to programmatically distinguish European from non European call sign?

Any ham radio log processing app developers? I am creating web application to manage our club award and I need to programmatically distinguish European from non European stations by call sign. I cannot find viable solution so any hint is valuable. I…
Pedja YT9TP
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4 answers

What might this tower be used for?

This tower is located on the campus of my wife's employer. She's asked around but no one seems to know the purpose of it. Does anyone have any idea what this may be used for? Edited to add Additional Information: This tower is located on a…
Lance
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3 answers

Noticeable difference between trunk and roof mount?

Between trunk-mounting and roof-mounting a 2m/70cm antenna, both as through-hole NMO mounts, is there really that big a difference performance-wise? I mean, I know roof mounting is better, but let's face it: looks are a factor for some of us (and…
Dominick Pastore
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2 answers

Can I use a CB antenna with a ham radio?

I just passed General and purchased a FT-450D with an internal antenna tuner. While my ultimate plan is to use a G5RV, it will be a while before I can get it up. What modifications would I need to make to use a mag mount CB antenna. Would it work…
Adam KC0DAD
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How to transmit images and video through a hurricane?

Background You're in the path of a hurricane, and the eye just passed over your head. There is no electricity (apart from your own generator or battery), there is no mobile network and there is obviously no internet availability. But you do have a…
not2qubit
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