Amateur Radio Stack Exchange
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1500 questions
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1 answer

How can I establish a wireless link between my PC and TenTec 506 / chipKIT UNO32 using USB port?

I have a TenTec 506 HF transceiver that uses a Digilent chipKIT UNO32 microcontroller. My PC running Teraterm (serial connection) or the MPIDE monitor is connected to the microcontroller's mini B USB port to read frequency, RIT, voltage, etc. I…
Terrance Leach
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Does antenna width/shape affect resonant frequency like length does?

I was wondering if I made an antenna from a Rohn 25G tower, would it have the same resonant frequency as a pole of the same height (assuming guys are insulated)? Also with the Rohn antenna, the waves would be both vertically and horizontally…
Synaps3
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What am I responsible for on my link?

I have set up an AllStar link system to a repeater depicted in the picture below: The repeater is under NØMHU's call, and my node is under me, KDØWHB. With permission, I service EchoLink and AllStar to the machine for wide coverage access. I am…
Skyler 440
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USB-C 15v won't power full portable radio

I bought this USB-C to 15 volt, thinking it might allow radio to work with any USBC laptop charger, USBC power bank/car charger, etc. https://www.newegg.com/p/2B7-003A-00052?Item=9SIA20PJYZ7273 It gives nearly exactly 15v. I plugged it in to a…
NoBugs
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Why the value of IF of AM is 455 kHz?

Why the value of intermediate frequency (IF) of amplitude modulation (AM) is 455 kHz? Why not another value?
Wei-Cheng Liu
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4
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4 answers

dBi gain of random wire antennas

All antennas are a compromise. Are there any antennas that in free space perform strictly worse than an isotropic antenna would? Or a simple flat ground model? This is what has been bugging me. I am a very new ham, especially with HF. I only have my…
Captain Man
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4
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Does a transceiver radio have a "receiving range"?

I'm familiar with the fact that a transceiver radio has an effective transmission range that is affected by several factors, such as the antenna, transmit power, obstacles, etc. I'm wondering if a transceiver also has an effective "receiving range"…
ajthealchemist
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Is there really a shielding of low-level audio frequency signals (e.g. for microphones) in the factory-made cables with (plastic) RJ45 connectors?

There are several schematics that show, for example, a MIC signal line in a 6- or 8-conductor ribbon cable for crimped RJ45 connectors that is marked as shielded. The shield is shown as the adjacent wire in the cable (MICE, microphone earth in this…
ha3flt
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Antenna - vertical & beam antenna transmit at the same time?

Is it possible to use a vertical antenna and a vertical polarized beam antenna at the same time? I have a friend that lives about 7 miles away & I can talk to him on 220MHz FM just fine on a vertical antenna. Another friend that lives about 13 miles…
Mike
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How to tell if a vacuum tube has gone bad?

Because it was $5 on my local classifieds, and I have a bit of a weakness for old junk, I bought myself a Heathkit HW-30 "Two-er". I've been going through the alignment procedure in the manual and have been pleasantly surprised at how well…
byl
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How does FM preemphasis interact with maximum deviation?

I'm trying to design a broadcast stereo FM transmitter in GNU Radio and I'm running against an issue. After preemphasis is applied using the built-in "FM Preemphasis" block, the amplitude of higher frequencies (> 4 kHz) can get boosted beyond 1 when…
Cosinux
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Discrete-Component Mixer design

I was building a radio receiver for FM waves (87.5-108MHz), I want to build every block on my own (oscillators, mixers, demodulators) and then put them together. I was now designing a mixer and i choose a Gilbert-Cell Mixer. I wanted to know If…
Chiranka K
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LoRa APRS using RaspberryPi 4B controlling an SX1278 transceiver

Project Description I am building a tracking & telemetry system for a stratospheric balloon that broadcasts an APRS message via a 433MHz LoRa transmitter (SX-1278 chip). To test the components and architecture, I wrote some code to send an APRS…
Austin
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Is this mystery antenna suitable for ham radio?

Brand new amateur radio license holder, and I know next to nothing. I just got my mobile radio: Anytone D578UVIIIPlus. The base station accessory bundle I also got, came with this vertical antenna: AnyTone Tri-band Mobile DMR Antenna. I'm interested…
Jared
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Counterpoise for telescopic antenna AL-800 as a portable/base antenna on 70cm?

Recently I bought a telescopic antenna, model AL-800: http://www.pryme.com/index.php?l=product_detail&p=2155 It is 863mm (34 inches) long when fully extended. When retracted, it is 785mm long. Will adding, for example, 4 ground radials increase the…
Marc
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