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1500 questions
10
votes
3 answers
Why prefer LC oscillators rather than RC oscillators in RF design?
I don't recall ever seeing an RC oscillator driven RF transmitter or receiver.
What prevents people from choosing RC oscillators in RF design?
Adam Davis
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10
votes
2 answers
What is the expected microphone input voltage level of a handheld transceiver?
Ok, so I'm looking to inject some computer generated CW into a little handheld rig by wiring direct into the mic input line. What sort of voltage is expected on this input, are we talking uV, mV or even Volts?
user521
10
votes
2 answers
Grounding VHF base station antenna
I'd like to install an outdoor dual band VHF/UHF base station antenna, a simple pole antenna like the Comet GP-1.
I live in an area where lightning is rare, but not unheard of. Should I drive ground rods into the ground for antenna/RF grounding? The…
Johnny
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10
votes
3 answers
Do I need to actually lock up my station?
Per §97.103, one is responsible for the proper operation of one's station, which of course includes that no unlicensed person uses it to transmit.
I have heard suggestions (no link handy, sorry) of taking actual physical security measures such as…
Kevin Reid AG6YO
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10
votes
2 answers
What is meant by "poles" when discussing filters?
I was looking over the product page for the K3 (dreaming I know) and noticed that they offer a variety of crystal filters. Some are 5-pole and some are 8-pole, other than price, what is the difference and what is meant by "pole" in this context?
WPrecht
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10
votes
2 answers
Scoring quality of Morse Code "fist"?
When learning, teaching oneself, or training a class in Morse Code sending using a hand key, how can acceptable quality be scored (other than the letters being correct terms of dot-dash sequence)? There a big difference between the dots being a bit…
hotpaw2
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10
votes
1 answer
What Part 97 rule allows unattended, automated transmissions, such as APRS weather stations and beacons?
What rule allows Amateur Operators to establish and operate remote, automated stations like APRS weather stations or beacons?
Are there different rules specifically for beacons, or do they all fall under the same rules?
Adam Davis
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10
votes
3 answers
What is the difference between FCC station and operator licenses?
I an studying for my technician class examination, and I came across this question:
What may result when correspondence from the FCC is returned as undeliverable because the grantee failed to provide the correct mailing address?
A. Fine or…
KQ4JWT
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10
votes
4 answers
Why are there so many coaxial cable impedances?
Why do we have 50, 75, 62 and 92 Ω coaxial cable, to name a few? Why not just one standardised cable? Is there some technical reason or did Mr. Coax and Mr. Cable have a disagreement, like Mr. Tesla and Mr. Edison?
R Johnson
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10
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1 answer
What does a lightning bolt symbol next to an antenna connector mean?
On the back of my Yaesu FT-897, next to each of the antenna connectors, there are lightning-bolt-ish symbols. What do these mean, and is there something I ought to be doing because of that?
I have not found any description of a meaning for these…
Kevin Reid AG6YO
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10
votes
2 answers
What is the most common amateur identification practice for mobile US amateurs operating in Canada?
When a US Amateur operates in Canada, IT and Canadian regs permit some lattitude on their identification. I have read that some will prefix a "VE3" plus their own home callsign (Ontario, meaning I am in Ontario right now, but my real callsign is the…
Warren VA7WPX
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10
votes
4 answers
Operating proceedures: testing an HT against a repeater?
Assuming proper licensing for the frequency, what is the proper operating procedure to test whether an HT works and is within range of a (documented as open, 2M or 440) club repeater?
Should one wait till someone comes on the repeater, and ask them…
hotpaw2
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10
votes
1 answer
Why do SDR control apps have two frequency settings?
Why do many SDR control apps have two frequency settings, even when the app is designed or set up only for listening to or decoding one signal? Should the two SDR frequency controls be set differently or the same? If different, how much for which…
hotpaw2
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10
votes
1 answer
How does a switching mixer multiply the two signals?
I understand what a mixer does, and when I see it in a block diagram it's obvious what purpose it serves and how it fits in the overall design of the radio.
However, when I look at the schematics and see how it's created, I don't understand how it…
Adam Davis
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10
votes
1 answer
How do I design a round or square coaxial transmission line to have a specific impedance?
Certain Hex Beam antennas use a coaxial center support post to send the RF to each antenna section, which is superior, in terms of maintenance, to a post with screw terminals connected by short lengths of coax used in previous designs.
I'd like to…
Adam Davis
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