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1500 questions
13
votes
2 answers
Do volunteer exam coordinators provide accommodations for applicants with visual impairments?
I am a prospective HAM, and I recently began reading the ARRL's third edition of their Ham License Manual, published in 2014.
Anyhow, under
WHO CAN BE A HAM
They mention that there are ham operators who may have disabilities that might affect how…
The Harmonic Rainbow
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13
votes
3 answers
UHF FM power amplifier design without expensive software
I'm designing a small UHF data transceiver for the 70cm band, based on a Silicon Labs EZRadioPro Si4463 IC. Modulation is FM, 12.5kHz channel step. The concept is similar to SiLabs' AN656 application note but with a different power amp BJT as the…
philpem
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13
votes
4 answers
Can I operate in the United Kingdom with a US license?
Can my license from the United States be used to operate while I'm in the United Kingdom?
Timtech
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13
votes
1 answer
Is it a good idea to build your own radio transceiver today?
With all the advances in the field of electronics, microcontrollers, etc., is it a good option today to build my own amateur radio transceiver (or transmitter/receiver)? Why might one choose to build over buying, or the other way around? How should…
kR105
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12
votes
1 answer
How can I calculate the effects of an LNA, antenna gain, etc. on noise performance?
There are many things I might do enable my station to hear weaker signals that would otherwise be buried in noise. Just a few possibilities:
Install a nice LNA
Increase antenna gain
Reduce feedline losses
Buy a better receiver
Move to a quieter…
Phil Frost - W8II
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12
votes
2 answers
What does a SSB frequency actually indicate?
An SSB signal is an AM signal with the carrier and other sideband filtered out, if I understand correctly.
As such, when specifying an SSB frequency do you specify the carrier frequency, then state which sideband, or do you specify the frequency the…
Adam Davis
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12
votes
1 answer
Is there a special name (and if so what is it) for this flush-style SMA variant?
I have some radios that have a special antenna connector. It looks like an SMA connector, but the dielectric is flush with the end of the connector:
rather than recessed the way "normal" SMA connectors are:
The consequence of this is that the…
user3486184
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12
votes
3 answers
Resort FM radio station
I stayed at a resort in the U.S. recently that is located in an unpopulated area with virtually no radio reception. To fill the gap, the resort has its own FM station that can be heard only within the resort (about a minute after you drive off the…
JoelFan
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12
votes
1 answer
How is the IF for a superhet selected?
There seem to be almost as many choices for the intermediate frequency (IF) as there are superheterodyne receivers and transceivers out there. The ones I have come across are 455 kHz, 452 kHz, 1.6 MHz and 6 MHz.
What would be the rationale for…
VU2NHW
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12
votes
1 answer
Why does the FCC put restrictions on symbol rates?
This answer claims that
Mostly, on HF, the FCC has chosen to limit modes of transmission and symbol rates rather than bandwidth
Why does the FCC limit symbol rates?
Geremia
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12
votes
3 answers
What "test transmissions" are allowed above 51MHz?
The ARRL's band plan chart includes the following text in its legend:
Test transmissions are authorized above 51 MHz, except for 219-220 MHz
What FCC regulation is this referring to?
Aren't all ham bands available for transmitter testing and other…
natevw - AF7TB
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12
votes
4 answers
Amateur radio in an EOC?
Consider a small town's emergency operations center. While there are amateur radio operators involved, they primarily work for government or public safety, and there is no active ARES participation. The EOC is reasonably well-equipped, with…
Dan KD2EE
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12
votes
2 answers
What kind of antenna is that one?
Yesterday I saw the following antenna:
I am very puzzled, at first glance it seems a simple dish but:
The mesh is really wide (low frequency?).
It is pointing to Zenith. I think that most dish antennas rest in zenith position to offer less…
Seitam
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12
votes
2 answers
How to do APRS in real wilderness?
I'm a relatively new ham (licensed a couple of years ago, occasional activity on 70cm and 2m, mostly repeaters). I'm looking to extend my ham experience and am interested in digital and packet modes.
I'm interested in APRS. The main reason is to…
hamster
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12
votes
3 answers
Why isn't twisted pair used for feedlines?
My son was asking about some Ethernet cable (Cat 5 unshielded twisted pair), and since he recently passed his Technician exam and we both have "radio stuff" on our minds, I tried to make the analogy between coax transmission lines and the balanced…
natevw - AF7TB
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