Amateur Radio Stack Exchange
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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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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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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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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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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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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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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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Can I improve reception with a more sensitive antenna / preamplifier / better feedline?

I am trying to receive a station, but I can only barely hear it through the noise. Will doing anything that increases the signal from my antenna help, such as: using a more sensitive antenna adding a preamplifier installing a shorter or higher…
Phil Frost - W8II
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How to design a Local Oscillator for a radio receiver?

I have decided to design a Medium Wave radio with discrete parts which won't include much complex ICs or schematics . I am thinking of designing the radio in Heterodyne mode. Which requires an oscillator for resonance and mixture. I think Hartley…
CoderBittu
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Can APRS and other AX.25 packet-based systems (ie. a BBS) use the same frequency?

I realize that it is technically possible to multiplex APRS and other AX.25 traffic on a single frequency, but I'm wondering if this is frowned upon or not. My hunch is that it is, but I wanted to see what other folks had to say as well. My use case…
Andrew Young
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What was the first QSO by an astronaut? Was it code or voice?

Discussion under this answer to Could amateur radio operators or others contact the ISS against NASA's wishes? in Space Exploration SE explore some activity from the Mir and ISS stations and the Space Shuttle, but I'm curious about the first proper…
uhoh
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GNU Radio and OsmoSDR AGC for Hack RF

I am trying to construct an automatic gain controller for my HackRF when in receive mode. I am using the gr-osmosdr block in GNU Radio to interface with the HackRF. I am then running my received I and Q signal into a squaring block, and then an…
Severe-Building-8307
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Repeater signal drops at regular interval

Relatively inexperienced ham, starting to call into local nets. With two of the local repeaters the signal drops at regular intervals, approx every 15 seconds. I’ll have a strong signal and then nothing for a fraction of a second. I’m on a HT with a…
mbond
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What does <...> mean in FT8?

I caught this in FT8, did someone just enter <...> as their call sign or is this code for something?
Pablo Fernandez
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