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1500 questions
5
votes
3 answers
Why are contest signal reports always "59" or "599"?
I've heard lots of contest exchanges, and the signal report almost always seems to be 59 for phone or 599 for Morse, even when the operator giving the report has to request information to be repeated several times. Why is the signal report almost…
rclocher3
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Characteristics of a "bad fist"?
What are some characteristics, when sending CW, of a "bad fist"? How bad can it get, typically, and still manage to communicate the message text sent to a human operator on the receiving end?
Contra-wise, what (slight?) variations from machine…
hotpaw2
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1 answer
What is the best frequency to start working EME on a budget?
Well, the title says it all: I want to start making EME contacts with the lowest possible budget, and I doubt between 2m, 70cm and 23cm. Since I cannot afford those expensive power amplifiers for these frequencies, I decided to go for a big yagi…
user3141592
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How does this W6NBC "derivative of the classical slot antenna" work?
Via the https://ham.stackexchange.com/a/9883/1362 answer regarding a slot antenna for a 2m mobile application, I was introduced to this (pdf) interesting antenna design:
The designer John Portune (W6NBC) introduces it as "a derivative of…
natevw - AF7TB
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5
votes
2 answers
What are these antennas?
On a recent trip to China I photographed a number of "antennas" that I do not recognize. Are they even antennas?
VE3LNY
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5
votes
2 answers
Can the parallel capacitance of a quartz crystal be directly measured?
A quartz crystal is often represented by this equivalent schematic:
simulate this circuit – Schematic created using CircuitLab
How to measure quartz crystal motional parameters using a VNA? discusses measuring these parameters with a VNA, and there…
Phil Frost - W8II
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5
votes
2 answers
How does this quarter-wave stub balun work?
I was searching for 1:1 balun designs that would be efficient at VHF yet could easily be made from commonly available materials when I came across these two:
While the design on the right seems pretty straightforward, the workings of the left one…
Ivan R2AZR
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1 answer
How to prevent cracking the capacitors in my diplexer?
Just made my first 2m/70cm diplexer. Important: I aim to be able to use this up to 50 Watts.
S21 from the LP section:
Having access to regular distributors such as Farnell/Element14, Mouser, Digikey,... I searched for RF capacitors with a voltage…
Dieter Vansteenwegen ON4DD
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3 answers
Confusion about dipole standing waves and feed point impedance
The animation below from Wikipedia shows the standing waves of voltage and current on an ideal center fed resonant half wave dipole in free space.
The red and blue curves show the change in amplitude of the actual voltage and current which exists…
Andrew
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1 answer
Measuring Output Impedance of an RF (HF/VHF) Active Circuit with Hobby-level Tools
Is there a simple (by simple, I mean a hobby friendly method that trades some accuracy for expense) method of measuring the "actual" output impedance of an active or "hot" RF (HF to VHF) circuit?
As an amateur radio enthusiast, I often find myself…
Buck8pe
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4 answers
Common-mode current and choke placement
Why are chokes usually placed at the feedpoint, can't common-mode currents occur below the choke as well?
I understand it's placed at the feedpoint to keep everything balanced by eliminating common-mode currents on the outside of the shield, but i…
t252
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2 answers
How to calculate power transmitted by monopoles?
I only studied monopole in sending mode or receiving mode alone but never in both modes together, I have this question which says:
Two vertical λ/4 monopoles are parallel to each other with 20 meters
separation between them at 5 GHz. The first…
user17194
5
votes
2 answers
Choosing simplex frequency as a technician
My brother and I just got our technician class license. We live close enough to each other that we can use simplex on 2 meters or 440. How do we go about choosing the best frequency to use?
Mike Grace
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1 answer
Change of Address and Callsign Zone
I'm about to permanently move to another US state, which is in another callsign zone. Will I be forced to get a new callsign in the new zone?
Also, when I started, when one was traveling in another zone, one was required to identify that fact, e.g.…
Bill Foote
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5
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2 answers
Beginner listening to a repeater - only hearing one station
This morning I tuned in to a repeater about 12km from me (in the UK). I could hear activity, but from only one station. I could tell that there were other stations using that repeater from the comments of the station that I could hear. Why couldn't…
Adam
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