Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

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1500 questions
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2 answers

What makes amplifiers so expensive?

Why are amplifiers so expensive? What is in it that makes them so expensive? My research suggests that the cheapest amplifier is >$2,000. The most expensive one is the new ICOM 1kW amplifier, and it costs $5,500. It's just 400 more watts, why is it…
John Doe
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Center frequency spike on software radio for mismatched/disconnected antenna

A while ago I was using a software radio receiver to perform some antenna analysis. I left the spectrum display on while disconnecting the cable and noticed that when the cable was disconnected I could see a very large spike in the frequency…
mtrberzi
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Is it possible to remove the previous callsign information?

I had a name change some years ago and had a new callsign generated. But the FCC keeping a record of my previous callsign puts me at risk of an abusive ex finding me. Is it possible to disassociate the old callsign from my FCC record so there's no…
MuffintopBikini
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Has any computer been hacked over amateur radio digital modes?

We don't normally worry about security in ham radio, because we can't encrypt our transmissions anyway in the vast majority of cases. Some niche protocols support authentication of messages, but that's it, unless you're controlling satellites. There…
Someone
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1 answer

How do you solder/crimp a 90-degree BNC connector?

I ordered this 90-degree BNC connector, but I'm not sure how to connect the center pin. The back of it looks like this: The small screw plate threads into the back when you're done connecting the wire. But how does the wire connect? The hole is…
KJ7LNW
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7
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7 answers

Amateur Radio License: USA or Canada, does it matter?

I'm hoping to take the exam in the fall. My question is, does it matter whether I do so in the US or Canada? I would like to operate the radio at my school in Canada, but I do get the chance to come the US, so I can potentially take the exam there.…
user1488
7
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2 answers

Practical 80m vertical wire antennas without radials?

We'd like to install an antenna for 80m at our club/contest station. Our club, OH2K, is housed at a school, and we can't fill the roof with a radial mesh. The roof is not metallic itself, either. We already have a horizontal dipole, but would like…
oh7lzb
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Are "end-fed" antennas really more multi-band than dipoles?

Several "end fed" antenna kits (including the ARRL's for example) include wording suggesting that they are useful as multi-band antennas. But does feeding a wire antenna highly off-center with a transformer/balun/unun actually allow it to radiate…
hotpaw2
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How does a Large Loop Antenna work physically?

I am learning about loop antennas at the moment. I read that the response of a small loop Antenna is proportional to the rate of change of magnetic flux through the loop which causes a uniform current distribution in the loop. This would be…
kinu
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1 answer

Can we use UHF/VHF ham bands for search and rescue missions?

Suppose that several licensed amateurs are part of a volunteer search and rescue team. The team is normally licensed and carries equipment to communicate on a variety of public safety bands in VHF/UHF during missions and training, and we are allowed…
crasic
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Do ethernet-over-power adapters interfere with radios?

I remember not long ago seeing a lot of chatter in the ham community about large-scale "Broadband over Powerline" (BPL) systems causing harmful interference across several bands. Does similar interference happen with SOHO "Ethernet over Power"…
KJ4JTN
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Is it ok to use a length of wire as an RX only antenna to test my new radio?

I have almost finished building my first shortwave transceiver kit (mcHF). Remarkably it's fired up and not gone up in a puff of smoke. The kit still needs some finishing off and I need to decide on an antenna solution, but in the mean time I'd…
rcx935
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1 answer

Why ferrite-core transformers are wideband while air-core are not?

While experimenting with end-fed antennas I've made two 1:49 transformers. The first one has an air core, as shown in the article by John, M0UKD. This transformer doesn't even work as a transformer until you add a capacitor in parallel to the load.…
Aleksander Alekseev - R2AUK
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7
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Simple circuit for acceptably clean CW in homebrew TX?

I'm working on a design for a home-brew 10 metre transmitter for CW. My oscillator is running cleanly, and I need to add a (small, probably 1/2 ~ 1 Watt) power stage to it, and I need to "modulate" the signal--i.e. turn the output on and off :) I…
Toby Eggitt
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Are there any active ham satellites orbiting that use the 5cm band?

I see that 5cm is available for satcom in amateur radio. Are there any active satellites for that? If so, what satellites and are their TLE's available?
KJ7NLL
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