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1500 questions
5
votes
4 answers
How does a receiver know the exact frequency in the channel to "listen to"?
I am reading about how radio communication works and I have an unanswered question.
We have wideband channels with 25kHz of radio spectrum. The transmitter modulates a signal and sends it.
The receiver that captures that particular channel and…
kkris1983
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5
votes
3 answers
Feeding a folded dipole
Can I feed a folded dipole constructed of hollow tubing by threading coax through the element to create both an impedance transformation and balun? I have fed coax through the tubing of the dipole from a point opposite the feed point and soldered…
R Johnson
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5
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1 answer
Can I use CHIRP for programming a Baofeng DM-5R?
I can't find my Baofeng DM-5R in the CHIRP list of supported radios. I've been told that I should try by telling CHIRP to assume a different radio from the DM-5R - perhaps the UV-5R!? Do you know if this is a feasible option? I am able to manually…
Phil Carter
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5
votes
3 answers
Only noise, no signals whatsoever on HF
Last night there was a power outage at home. I was able to see a LOT of stations on 20M (FT8). As soon power returned, all of them disappeared. You can see in the waterfall very clearly when power returned:
The odd thing is, noise is around 7 here…
hjf
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5
votes
3 answers
What is the proper way to electrically wire in a loading coil to a vertical antenna?
I am trying to put together a vertical pole style antenna with a loading coil housed at the base using a plan very similar to the one described in this ARRL article. I am trying to understand how to electrically wire it though.
For convenience, the…
SandPiper
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5
votes
1 answer
Is a gradual power-up recommended for non tube based radios?
It used to be that if you wanted to power up an old tube radio, you'd use a variac and gradually bring up the line voltage to avoid damage to the radio.
Is this needed or suggested for transformer powered semiconductor radios that have been sitting…
Adam Davis
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5
votes
1 answer
How do I put an RJ-45 connector on to repair a Kenwood MC-59 microphone cable?
I've got a Kenwood MC-59 microphone, which started fraying around the place where the mic cable goes into the body. I thought I'd cut it off and put a new RJ-45 jack on it.
After cutting the cable, I discovered something completely unexpected.…
user3486184
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5
votes
2 answers
How to estimate ladder line loss?
There have been a number of questions regarding the issue of feed line loss and ladder line eventually gets discussed. So I am curious, how does one begin to estimate the loss in ladder line?
So, for the case of 2 bare wires "somehow" spaced an…
Chris K8NVH
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5
votes
2 answers
Pros/cons of the PL259/SO239 connector (M type)?
What are the pros/cons of the PL259/SO239 connector (M type), and why is it used preferentially on civilian rigs vs military?
Timtech
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5
votes
1 answer
How do I determine antenna spacing?
How do I determine antenna spacing so that I don't end up overdriving the front end of a receiver when transmitting?
Timtech
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5
votes
5 answers
Why are some electrical connectors silver plated?
Silver is pretty expensive. Unlike gold, it will tarnish in air. Why then would anyone bother to plate connectors with it? Does it have some unique electrical characteristics that make it useful?
Phil Frost - W8II
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5
votes
8 answers
Why are some electrical contacts gold plated?
Gold is really expensive. Why then would anyone bother to plate connectors with it? Does it have some unique electrical characteristics that make it useful?
Phil Frost - W8II
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5
votes
2 answers
Abilities to limit antenna use?
What kinds of abilities does a Home Owners' Association (HOA) in the United States have to limit the use of antennas placed on a roof to an owner of a home in the area?
Timtech
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5
votes
2 answers
How to construct a loop antenna for receiving HF?
I have a unused hula-hoop in my garage, and I ran some stranded speaker wire around it once, and attached one side of the wire to the coax shielding, and the other to the coax core wire. Is this the correct way to construct a loop antenna for…
cj5
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5
votes
1 answer
What radio regulations apply in International waters?
What regulations apply to radio operations in International waters? How far offshore does one need to be? Does the answer change between registered commercial vessels and home-made rafts or canoes?
hotpaw2
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