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1500 questions
13
votes
2 answers
Why is an exemption for music given to NASA broadcasts of manned space flight missions?
FCC 97.113 Prohibited transmissions reads:
(e) No station shall retransmit programs or signals emanating from any type of radio station other
than an amateur station, except propagation and weather forecast
information intended for use by the…
PearsonArtPhoto
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13
votes
6 answers
Calculating Antenna Length on the FCC Exam vs. in Reality
I have seen the following formulas for calculating half and quarter wavelength antennas:
Formula for $\frac{1}{2}$-wavelength antenna (in free space):
\begin{equation}
\mathrm{Length~(feet)} = \frac{492}{f_{MHz}}
\end{equation}
Or is…
Dan
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13
votes
5 answers
Is an antenna analyzer necessary for building antennas?
I'd like to try my hand at building a few antennas for VHF/UHF use. I'm going to be going approximately from established designs, but obviously the final result will require some tuning. I don't currently own either an SWR meter or antenna…
David KF4MDV
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13
votes
2 answers
How are secret encodings not a violation of amateur radio regulations?
This question asks if proprietary encodings are "in keeping with the nature of" of ham radio. The accepted answer notes, at least in regard to FCC regulations, that if anyone can buy encoders and decoders (as hardware or software), then it's not…
Mark Adler
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13
votes
1 answer
Is there any legal recourse against unauthorized usage of a private repeater in the USA?
Can the FCC revoke an amateur license for unwelcomed use of another amateur's private/closed repeater system?
It's clear that private repeaters are allowed, per 47 CFR 97.205(e):
Limiting the use of a repeater to only certain user stations is…
natevw - AF7TB
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13
votes
3 answers
How do I troubleshoot a Baofeng UV-5R that won't receive?
I have a couple of Baofeng UV-5R radios. I have a profile in Chirp that works great on one of them, and I foolishly pushed that profile straight over to a UV-5R without checking firmware versions. Chirp crashed, and now the radio won't receive. …
Benson
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13
votes
1 answer
Hanging a dipole from a tree not code compliant?
I just got off the phone with my town's electrical inspector (in Massachusetts), and he informed me that you are not allowed to hang anything electrical from "vegetation". He said if I did this with my dipole, that it would not pass inspection. He…
Bonfire
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13
votes
4 answers
Hearing Morse code after end of session?
Does anybody still hear phantom Morse code in your brain after ending a session? I'm hearing random beeps that definitely don't come from an external source.
I tried to search Google but couldn't find anything on this topic.
itsaunix
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13
votes
4 answers
Why does ice on a wire dipole affect the SWR?
We just had snow and ice overnight and my wire dipole was coated in ice. Why does the ice covering negatively affect the SWR of the antenna?
Ron J. KD2EQS
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13
votes
4 answers
Are Baofeng radios illegal in the U.S?
Having a low price budget, my search for my first ham radio to buy has led me towards Baofeng. A quick Google search on baofeng showed a lot of results that said that certain model baofeng handhelds are illegal in the US. Is that true?
hopefulhacker-Reinstate Monica
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13
votes
2 answers
Is there an optimum Antenna Feedline Length for mobile installations?
I bought a ham radio antenna mounting kit for my car that includes ~16' of coax. One end has a trunk lip NMO antenna mount, the other end has a re-solderable PL-259.
I asked the sales person if it is best to shorten the coax after installation to…
BenSwayne
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13
votes
1 answer
How do Radio Regulations and Frequency Allocations Apply to an Ionosonde?
An ionosonde is a special HF radio transmitter that periodically transmits a signal that sweeps across a large portion or the entire HF spectrum to identify the propagation of radio signal in the ionosphere, currently they are operated by various…
比尔盖子
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13
votes
3 answers
How is "clarifier" control helpful?
My radio-club recently got a Yaesu FT-225RD transceiver and I'm trying to digest its manual (available for download here). This is the first ham radio that I'm learning how to use, so I could be missing something obvious.
On the front panel there's…
AndrejaKo
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13
votes
3 answers
Bandwidth of a CW signal?
What is the RF bandwidth of a typical CW signal? How is the signal bandwidth affected by WPM and/or transmitter rise-time?
What is the narrowest bandwidth that can still be copied by a human? Or what is the narrowest receiver audio filter that…
hotpaw2
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13
votes
4 answers
Why do today's transceivers use LC filters rather than crystal filters?
Going through a number of schematics for today's receivers (Elecraft KX3, for example) I note that most use LC circuits for filtering. The wikipedia article for Crystal Filters suggests, however, that crystal filters are used in high quality…
Adam Davis
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