Amateur Radio Stack Exchange
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How can the design of an RF filter also encompass impedance matching?

I'm installing an antenna which will require a matching network. (A fixed network: the load will not change.) I'm also building some low-pass filters to reduce transmitted harmonics. It would be a simple exercise to design an ordinary 50Ω filter…
Phil Frost - W8II
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I would like to listen to a red roadster in space

I have been listening for signals (any) of the Space-X Falcon Heavy. Just out of curiosity. And I am wondering if anyone has received any. According to the Falcon-9 User Guide table 4.6 looks like this: Although it mentions "Falcon launch vehicles"…
Edwin van Mierlo
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HF/VHF antenna for high altitude balloon

I'm working on the design of a dual band transmitter for use on a high altitude balloon. I'll be transmitting on 2 meters and 20 meters (APRS and WSPR) with about 50 mW. To keep the weight to an absolute minimum, I'm designing it to use a single…
whalphen K8VFO
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QSL cards and distance minimums

Newly licensed HAM here. Are QSL cards only exchanged during DX, or could they be exchanged with local contacts as well? How does one request a card? I’ve heard there are bureaus that route cards; is this the most appropriate way to send a card?
djdy
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Can a vertical antenna be used for NVIS?

I know that verticals are normally chosen for their low angles of radiation without obscene heights, but I'm not especially interested in DX and am primarily looking for local coverage via NVIS. I've not had great luck with dipoles at my home…
William
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How to access a P25 repeater?

Are there any special instructions for accessing a P25 repeater? What makes it different from a CTCSS/PL-tone-encoded repeater? What special features does a radio need to access it?
Dan
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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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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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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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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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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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