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1500 questions
5
votes
1 answer
Does geology affect radio signals?
following on from an earlier question about Iron Ore affecting radio waves... are there any other geological properties that can affect radio waves?
Are certain frequencies more susceptible to geology than others?
Diatu
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5
votes
1 answer
How would I go about setting up my own repeater in the UK?
How would I go about setting up my own repeater in the UK? For instance, what license category would I need, what equipment would should be looking to purchase, and do I have to register it anywhere?
berry120
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5
votes
5 answers
What type of solder is best suited for radio and electronic use?
Many types of solder are available today, such as acid-core, silver, rosin-core and aluminum solder. What kind should I use for building antennas and radio equipment? Why?
From test question: T7D08
JC Hulce
- 901
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5
votes
1 answer
Why is coax the most common feedline?
Why is coaxial cable the most common feedline in use? What are the advantages/ disadvantages of coax compared to other feedline types?
From test pool question: T9B03
JC Hulce
- 901
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- 16
5
votes
3 answers
Does a receiving antenna need radials?
I am very new to radio and am using two 433MHz 1/4 wavelength monopole antennas to send and receive data. On the transmitting antenna I'm going to add radials (as it is the standard in my application). However I wonder, would it help adding radials…
user5227744
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5
votes
1 answer
What frequency to set trap on?
I plan to build trapped multiband dipole so I read lots of documentation I found.
There is one thing that confuses me: various authors recommend setting resonant trap frequency differently: some say trap should be resonant just below wanted band,…
Pedja YT9TP
- 870
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5
votes
4 answers
What is the output impedance of a typical solid state ham transmitter?
I've often heard that the output impedance is 50Ω, and the load impedance should be matched to that and also 50Ω. While the reasons for the load impedance to be 50Ω are clear, is the output impedance really 50Ω and if so why? If it isn't 50Ω, what…
Phil Frost - W8II
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5
votes
2 answers
What ways are there to extend an antenna?
I am using an arduino micro controller with a LoRa radio module to communicate. The shield has 2 ways of connecting an antenna: either a SMA jack or a hole for soldering.
Now my problem is this: I need to get the antenna away from the module…
user5227744
- 295
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- 10
5
votes
2 answers
What are the requirements of the address given for a US licence?
I'm going to be visiting the US soon (I live in the UK), and since I've heard it's very easy to get a US amateur radio licence and it's something that could be beneficial, I thought, why not?
I see that it requires an address, though. What are the…
Muzer M0SWT
- 193
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5
votes
2 answers
What is the purpose of limiting radio output power?
According to article 25, section I, § 4 (25.7) ITU's Radio Regulations:
The maximum power of amateur stations shall be fixed by the administrations
concerned.
In my country this is 500W for CEPT License, 100W for CEPT Novice License, 1500W with…
Hex
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5
votes
3 answers
How to find or derive the maximum safe input power to a receiver?
A number of my RF devices have a specified safe maximum input power, for example:
"The maximum RX power of HackRF One is -5 dBm. Exceeding -5 dBm can result in permanent damage!" source
"If you look at the R820T datasheet … you can see the max…
natevw - AF7TB
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5
votes
3 answers
How to determine the PPM value of a NESDR SMArt?
a) Given that I don't have a frequency standard or other known transmitter available, what is the easiest way to calibrate the NooElec NESDR SMArt which is using a TCXO rated at 0.5 PPM.? I.e. to determine the PPM calibration value?
b) Also, is…
not2qubit
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5
votes
3 answers
How slow is slow telegraphy?
On the UK Band Plan there are frequencies stating “QRS (slow telegraphy) Centre of Activity”. For example, 14,055 kHz on 20m and 3,555 kHz on 80m.
What is considered slow? (<15 wpm?)
How close should you stay to the stated frequencies?
Phil_12d3
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5
votes
1 answer
What is the difference between "Cross Polarized" vs "Circularly Polarized" Antennas?
What is the difference between cross-polarized yagi antennas and circularly polarized antennas?
metropolis
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5
votes
3 answers
Radio manufactured in United States
I am just beginning with amateur radio and would like to start with an entry level handheld transceiver. I would like to consider manufacturers based in the United States, but I have not found any. Are there any USA handheld ham radio…
jcadcell
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