Amateur Radio Stack Exchange
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1500 questions
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Asynchronous vs. Synchronous data transmission speed

Humans are asynchronous receivers, they can pick up words at any time, even if spread out, can combine into a sentence. Data rates are as fast as someone can hear/talk/copy code. All of the fast digital modes are Synchronous, example the HF digital…
Skyler 440
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Is that a loading coil antenna

I came across one WiFi receiver of my wireless keyboard and after opening the USB receiver, I saw a strange looking printed antenna on the PCB. It's like a series of square waves printed on the PCB. Is that a loading coil antenna or something…
user29605
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How much of its receive spectrum is an IC-7300 or similar radio actually sampling?

I'm curious as to what the sampling strategy is for radios like the IC-7300. For example, I can set my waterfall display span to be up to +/- 500kHz around the tuning point, i.e. I can see a megahertz of spectrum in real time on the screen. So how…
QuantumMechanic
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how to stack parabolic antennas?

I've read that the distance between stacked antennas should be 0.5 to 1 wave lengths - does it mean stacking of parabolic antennas as e.g. for 13 cm EME is not possible? If yes then the only way to avoid large dishes is to build an array using yagi…
Romeo Kienzler
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Non-Ham satellite constellation call signs

In certain public FCC documents, call signs for non-amateur satellite constellations are mentioned, e.g.: Starlink: S2983/S3018, S3069 (Gen2) Iridium NEXT: S2110 OneWeb: S2963 But these are not available via FCC Universal Licensing System call…
mykhal
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How to make an inductor?

I am a high school student and am making a project on FM receiver for class 11. I am following this circuit diagram: The L2 in this diagram is a 22µH RF Choke. The part listed in the website has the configuration provided below in its datasheet. L=…
Aniruddha Sarkar
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Does the phase of an impedance mismatch matter?

Given two antennas with the same SWR of 1.5:1, is there any advantage to the one having an impedance mismatch that is closer to pure resistive (e.g. a resonant dipole in free space with an impedance of around 73 Ohms), versus an antenna with a…
hotpaw2
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PCB Yagi-Uda impedance matching and other smaller problems

I got interested today in writing a tool to automate design of PCB Yagi-Uda antennas for KiCAD after seeing this on Amazon. I thought, "how hard could it be to make a crappy 5.2GHz antenna I can have OshPark print for a couple bucks?" Turns out…
ttshaw1
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Decent 900 MHz radome material from a hardware store

I'm working on some outdoor Meshtastic nodes, and am considering materials for a radome to enclose the antenna, transceiver/host, and (possibly) battery all in one tube. The most important considerations are: Commonly available at any hardware…
Brad
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A first homebrew design: Band, antenna, and ground wave propagation

I'm working on a very simple homebrew transceiver and request review of our selected band, antenna, and power. Background: A child got very interested in ham radio, as an incentive for to earn his license and CW (way to go!), I committed to earn my…
SRobertJames
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Can the reactance on a transformer load, be "corrected" on the transformer primary, to improve transformer efficiency?

The following question is regarding the ability of a transformer, UnUn or BalUn, to be efficient, if the transformer (UnUn in my case), is feeding a load with reactance, and what can be done about the reactive load, on the transformer's input…
Louis Seaman
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Recommendations for starting out with HF for an amateur

I'm a beginner who's nearly half a year from receiving my ham license in India. I want to start with HF radio and wish to build my own rig. Currently I have looked and multiple designs using the ad9860 module. Also I live in a city and know very…
Parth Sane
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Effect of using wrong injected frequency when tuning IF cans in an AM radio?

I viewed an interesting video of a restoration of an old AM portable radio. When the alignment steps were being done, the author commented he would inject a 455kHz signal into the radio (the IF of the unit) then peak the output with the tuning…
rasher
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Longest achievable ground wave range on 40-meter bands

What is the longest possible range on the 40-meter band by ground wave? A reference said we can achieve 150 miles at 8 MHz with only a 100 watt transmitter. It also says on 160 meters, the ground wave may extend to more than 900 kilometers. Is this…
abduoman11
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Shifting Frequency of a VHF Crystal?

I have a boatload of 165.550 MHz Regency 10.7 MHz IF Crystals. I need them to resonate for 165.500 MHz. How can I shift the crystal frequency down 50 KHz without opening the 'tincan' and messing with it? Can I add a small capacitor in parallel to…
Station51
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