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1500 questions
6
votes
0 answers
Choice of PCB coil design for filter inductor at ca 20 to 400 MHz, 5 W
Looking at the diplexer schematic from this nice question,
I realized this can completely be done in PCB-formed elements (minus the connectors). (As a kind of counter-action to the original question's intent to get leaded capacitors, I'm not only…
Marcus Müller
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6
votes
3 answers
Is it ethical to accept sponsorship for QSL cards?
We all know that in general commercial activities are not welcome on amateur radio bands.
One thing that somewhat related to that came up in a discussion I had with some operators:
Is it ethical to accept money for printing and sending QSL cards in…
AndrejaKo
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6
votes
4 answers
Any reason not to choose a discone antenna over a Wide/ MultiBand mobile antenna for TX/RX operations
We are setting up a all-band radio in an emergency com center that's intended most for amateur band use, but since its' for emergency use will also be used in the public safety bands; (150-170)MHz, (470-512)MHz, (700/800)MHz, and possibly others if…
Frank
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6
votes
7 answers
Space Requirements
As I progress in my path to getting a ham license I notice that a lot of radio enthusiasts avidly talk about their radio shacks (or do they call it cabins?).
Do I need that much space to start?
Do I have to set up an antenna outside?
Will it work…
hopefulhacker-Reinstate Monica
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6
votes
2 answers
Why does capacitive loose coupling increase selectivity?
There are multiple ways to couple antennas. It is said that an antenna is capacitive loose coupled if a small capacitor is used between the antenna and the parallel resonant circuit (like C2 in the image below).
Such a loose coupling will increase…
dudekowsky
- 160
- 3
6
votes
2 answers
What are the regulation requirements for running a repeater?
When I try to find information on the requirements to run a repeater, I just see a lot of results related to building one. But I'm wondering about USA regulations.
Does one need a particular license?
Which frequencies are allowed?
Can/should…
Bort
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6
votes
1 answer
What's the difference between an APRS "item" and an APRS "object"?
What's the difference between an APRS "item" and an APRS "object"?
A kenwood manual says Objects have timestamps, items do not. What does that mean, and how should it be used?
Also in general: What is a good resource for learning about APRS?…
Thomas
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6
votes
2 answers
How to check HAM license status - India - Grade One License?
I got my HAM Radio License (Grade-One) License issued on 2005 year (New Delhi, India). Unfortunately Date of Termination of the license is missing. Tried reaching Helpdesk via E-Mail but not much help.
Is my Amateur Radio license still valid? If…
Vasanth Subramanian
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6
votes
3 answers
APT/LRPT images geotagging
I want to extend functionality of some open-source programs which decode APT and LRPT images (wxapt and glrpt). More specifically I want to add possibility to overlay geographical data such as land borders, administrative borders, rivers etc on the…
Drobot Viktor
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6
votes
2 answers
Looking for a schematic of a DIY circulator
I would like to build a simple HF, VHF or UHF circulator to get a better understanding of how these devices work. Sadly at the moment I'm unaware of any articles or books that provide corresponding schematics and description. Could you please…
Aleksander Alekseev - R2AUK
- 4,272
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6
votes
2 answers
Where to find HF channel models or statistics?
When designing a waveform for packet radio usage, it'd be helpful to know a few things, mainly
distribution of coherency bandwidths
distribution of coherency times
Whilst such statistics are reasonably possible to generate for higher frequencies…
Marcus Müller
- 15,910
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6
votes
3 answers
Where to apply for an amateur LTE radio license in the USA?
Where do you apply for a license to operate on the LTE radio spectrum for amateur radio in the USA? Can this amateur license be used to operate a cell phone independent of a carrier?
iphoneguy38440
- 67
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6
votes
2 answers
For a resonant 1/2 wave dipole, does the reflections being in phase with the applied signal cause the zero reactance seen in the feedpoint impedance?
For a resonant 1/2 wave dipole when used for transmitting, does the fact that the reflected waves on the antenna are in phase with the applied signal result in zero reactance at the feed point, or does zero reactance happen for some other reason…
Andrew
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6
votes
1 answer
Using shortwave communication, how difficult is it to transmit messages from the UK to the US?
Is it possible to transmit a short message via shortwave from the UK to the US, across the Atlantic ocean? From what I understand, long-distance shortwave communication has lower bandwidth requirements than other forms of communication, such as…
p.luck
- 163
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6
votes
1 answer
Does the FCC care about electrical arcs?
There are a lot of videos on YouTube from people who have built high voltage sources and are sending electric arcs from one place to another. Although they have no intention to emit radio waves, they are probably creating a lot of noise. I have…
Display Name
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