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1500 questions
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1 answer
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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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
3 answers
What is the difference between RIT and XIT?
What is the difference between RIT and XIT? When would one use one and not the other for split (or other) HF operation? When would one need both? Which one is more useful for a transceiver to have if it only had one?
hotpaw2
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5
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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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3 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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5
votes
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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5
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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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5
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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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5
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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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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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5
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2 answers
Can half of a directional antenna (Yagi-Uda, HB9CV) be replaced by a ground plane?
Consider a center-fed dipole antenna. It‘s well understood how the bottom element can be replaced by a ground plane (in practice, generally a few rods but in principle a conducting plate would work as well), creating a „groundplane antenna“.
I was…
jstarek
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5
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1 answer
What is the difference between a scanner and a receiver?
What is the difference between a scanner and a receiver?
Harold Chan
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5
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1 answer
Transmitting Callsigns
I started learning for my technician test and I noticed one of the FCC guidelines is that you have to
Transmit your callsign at the beginning of radio contact, and every 10 minutes
How does transmitting your callsign every 10 minutes work?
What…
hopefulhacker-Reinstate Monica
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5
votes
1 answer
What does a License look like?
What does the HAM license look like?
Is it a card? A document?
All I could find on google is ham radio license plates.
hopefulhacker-Reinstate Monica
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