Most Popular
1500 questions
17
votes
1 answer
How do emergency nets work?
In movies that depict amateur radio in emergencies, the hams' worldwide communication network invariably is able to pass messages between individuals. As an amateur that has been primarily interested in the technical sides of the hobby I am not at…
pyHazard
- 341
- 1
- 5
17
votes
4 answers
Using my Baofeng UV-5R to talk to walkie talkies
I have a few walkie talkies at home and sometimes I connect my UV-5R to them to talk to them and act as another walkie talkie. At one time, I built a little simplex repeater out of it. Should I not be doing this? I don't think the other walkie…
Skyler 440
- 7,690
- 9
- 54
- 90
17
votes
4 answers
What bands and modes will give me voice at 3,000 miles?
I pursued Amateur Radio primarily for local emergency communications and as part of my electronics education. My only radio right now is an inexpensive 2m/70cm HT which is good for local weather spotting and emergency operations.
I'm interested in…
Adam Davis
- 12,295
- 2
- 51
- 111
17
votes
4 answers
Are amateur radio call signs unique among all radio call signs?
Idle curiosity:
Are the call signs of amateur radio operators distinct from call signs in all other radio services, such that there can be no ambiguity even if the relevant license and band(s) of operation is disregarded?
If they are not distinct…
Kevin Reid AG6YO
- 25,080
- 7
- 55
- 106
17
votes
2 answers
Why is the solar-flux index measured at 10.7 cm?
Why is the solar-flux index measured at 10.7 cm? What makes that such a special frequency?
Dan
- 1,764
- 3
- 16
- 36
17
votes
8 answers
Should I chose a vertical or a horizontal HF antenna?
If I only have the budget for one HF antenna, should I chose a vertical or a horizontal antenna?
Timtech
- 2,376
- 2
- 26
- 40
17
votes
5 answers
If I receive an SOS signal, what is the proper response?
My 5-year old son loves sending out an SOS signal using a toy Morse code generator (wired, don't worry about false alarms for real authorities).
He has learned to send the SOS signal and was asking me to send a response to him to let him know that…
Hanky Panky
- 273
- 1
- 2
- 6
17
votes
4 answers
Understanding coax impedance
I keep doing research, and trying to grasp it, but when it comes to RF impedances, and coax, I still have trouble trying to grasp it.
So first, I think you have to have a 50 ohm coax for a 50 ohm transmitter to keep the impedances matched. I think I…
Skyler 440
- 7,690
- 9
- 54
- 90
17
votes
3 answers
Why do we not use AM and FM at the same time to transmit more information?
Amplitude modulation uses the modulation of the amplitude of a carrier wave to transmit data while leaving the carrier frequency constant, and in the case of FM it's just the other way round.
Why is a modulation of the frequency in an AM signal not…
DK2AX
- 624
- 5
- 13
16
votes
4 answers
What does the addition of a shield to a small loop accomplish?
A small shielded loop is an antenna with a loop of wire, smaller than 1/10th of a wavelength in diameter, also surrounded by a shield. Often, they are constructed from coax. There is a gap in the shield somewhere. Feedpoint arrangements differ among…
Phil Frost - W8II
- 52,635
- 8
- 91
- 225
16
votes
7 answers
What is the cause of this unusually long period of terrible HF band conditions?
I've been a ham for over 40 years, but never has there been such a prolonged period of such poor propagation. This has been especially the case over the past six months or so, and they continue to deteriorate.
What could possibly be the cause?
This…
Mike Waters
- 8,201
- 4
- 19
- 51
16
votes
4 answers
FCC tracking of unlicensed FRS/GMRS transmissions
If a transceiver such as the BaoFeng UV-5R is used to transmit over FRS/GMRS frequencies (unlicensed), it is illegal in the United States due to FCC regulations that state that the power must be <0.5W and that the radio must not have a detachable…
J. Taylor
- 271
- 1
- 2
- 7
16
votes
12 answers
How can I safely transmit without an antenna tuner or SWR meter?
Just what the title says.
An Antenna Tuner, henceforth AT, is almost a de facto piece of equipment in a shack; working the bands without one is tantamount to leaping off the diving board into a swimming pool with tarantula nests in it ... or…
VU2NHW
- 2,844
- 2
- 23
- 43
16
votes
2 answers
How does selecting the opposite sideband when receiving CW on HF reduce interference?
I am studying for my FCC General Class license, and question/answer G4A02 reads as follows:
Q: What is one advantage of selecting the opposite or "reverse" sideband when receiving CW signals on a typical HF transceiver?
A: It may be possible to…
Bryson
- 263
- 2
- 6
16
votes
2 answers
Is free space path loss dependent on frequency?
Free space path loss is calculated as:
$$ \left( 4 \pi df \over c \right)^2 $$
The presence of $f$ in this equation means that losses increase with increasing frequency, so there's an inherent advantage in lower frequencies, right?
Phil Frost - W8II
- 52,635
- 8
- 91
- 225