Amateur Radio Stack Exchange
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1500 questions
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1 answer

Morse Code Tips for B vs. 6 and V vs. 4

I am practicing receiving Morse Code with Koch's Method and Farnsworth Timing. As I increase speed, the places where I am running into trouble are distinguishing B from 6 (both are a dah followed by a few dits) and distinguishing V from 4 (both a…
plafratt
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RF ground confusion

I'm a bit confused by RF grounding. Let's take a HF 1/4 wave vertical antenna for example. When current flows through the centre of the coax to the antenna, my understanding is that the current then needs a return path, which is back through the…
Engineer999
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Why does beamforming bring more power to the received desired signal?

Consider a normal array model with $N$ element. The output of the array is given by, $$\mathbf{y}=\mathbf{w}^H\mathbf{x}=\mathbf{w}^H\mathbf{as}$$ where $\mathbf{a}=[a_1,...,a_N]^T=\in\mathbb{C}^{N\times 1}$ is the manifold of the desired signal (I…
tyrela
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2 answers

What radios compare favorably with the FT-817ND?

I've been asked to specify an amateur radio for a project which is very general purpose in nature, including HF, VHF, and UHF bands. Cost and user friendliness is a concern, so I wanted to avoid multiple radios and additional complexity when…
Adam Davis
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HSMM problems introduced by mismatched antenna feed points

I have been trying to understand the finer points of HSMM, and I ran across this statement about antenna feed points (emphasis mine): 802.11 signals produce very broadband signals, typically 20-22 MHz. There is evidence to date that indicates the…
Mike Pennington
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4 answers

3D Printed yagi antenna

I'm trying to produce a Yagi antenna for the 2.45 GHz band using a 3D dual extruder printer. The idea is to print the antenna elements using a metal filament and encasing it all in plastic. The antenna needs to be highly directional, with 8 elements…
PHOLAN
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Bicycle mobile antenna

I have mounted mobile verticals (mag mounts) on my bicycle, but I have learnt that a bike does not have a good RF ground because there is nothing close to a plane. Without wasting too much more space, what is a better antenna I can use for 2m/ 70cm…
Skyler 440
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What is proper procedure for asking for "distant" contacts on 2m FM on simplex?

As a new ham, just for fun, I'm planning to hike up to the local high point (which while not high in an absolute sense does have a commanding view of the surroundings) with my 5 watt FT-4XR and a slim jim antenna for 2m and see what kind of distance…
QuantumMechanic
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Boosting Mobile Phone Reception

Yes, I know, this could very well be a controversial topic, so feel free to close this off if you feel it's not a good fit for this site. That said, I'm posting it here because hams (and as a licensed ham, I count myself in that group) know a great…
Buck8pe
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1 answer

Is A7RW a legal call sign?

I've seen a reference to the callsign A7RW. I can't find it in the FCC database or by searching the ARRL. Is it a legitimate US callsign?
Roy Willis
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4 answers

Could keying cw with your mouth using a sip-n-puff be as efficient as doing it by hand?

I know Morse code is sometimes used by people with limited use of their hands to interact with their computer. One way is by using a straw connected to a pressure sensor, a so-called sip-n-puff or SNP. I've also read mentions of people with…
EdvinW
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7 answers

QRN: How to chase down a solid S9 noise floor on 40m only

I am new to this, having just set up my station. I have "very bad" QRN on 40m: S9. Here is the setup: High density suburb with flats and houses Yaesu FT450D with fan dipole at 6m-9m above ground (sloping), this is lower than a building with flats…
Oliver Schönrock
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2 answers

Stacking Two UHF Yagi Antennas

Aloha! I have two HYS TC-YG05 Yagi antennas that were gifted to me and I would like to stack them side by side ( Collinear), in the vertical orientation for some local weather balloon telemetry data gathering. I have attempted to use my Google-Fu as…
RF101
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How do I set up my radio for Echolink?

Need help in setting up the Kenwood TH-D72A for ECHOLINK. Cannot find if I need to connect to computer or some node through a local repeater.
Jerry
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4
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2 answers

Why are VLF EM waves labeled as "sonic" in ARRL charts?

In the ARRL Ham Radio License Manual (4th Edition) an Amateur Allocation chart labels VLF with "Audible Range": Very Low Frequency (VLF) 0Hz 10Hz 10kHz 100kHz Activities …
Jared
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