Most Popular
1500 questions
12
votes
5 answers
Does an amateur radio licence work worldwide?
Lets say that I get my amateur radio license in country A and then some time later I move to country B. Will I need to get a new license on country B or does the license obtained in country A works just fine?
kR105
- 363
- 3
- 10
11
votes
2 answers
Why do satellites receive and transmit on different bands?
Most satellites I've found transmit on VHF and receive on UHF or vice versa. Why is this? I would think there's enough space on a single band.
Skyler 440
- 7,690
- 9
- 54
- 90
11
votes
6 answers
Key CW on zero crossings - zero bandwidth?
I remember being surprised to learn that a CW signal has a bandwidth (albeit small), but when I thought it over, it made sense. Essentially, we are modulating the carrier with a low frequency square wave. This would explain key clicks: a perfect…
Dominick Pastore
- 555
- 4
- 16
11
votes
1 answer
Is FM modulation still more resistant to noise when given the same bandwidth as an AM signal?
FM modulated radio is much more resistant to noise and can deliver better sound quality than AM radio. But FM signals also use more bandwidth than AM signals. In general a wider bandwidth signal is more resistant to noise / can send more data than a…
JanKanis
- 415
- 2
- 11
11
votes
1 answer
What is body blocking, and does it work with a stock HT on a foxhunt?
I've heard that you might not need a special directional antenna to participate in a foxhunt, that some people are able to use their body to help determine the direction of a signal.
How does this work? More specifically, what is the process to do…
Adam Davis
- 12,295
- 2
- 51
- 111
11
votes
2 answers
Can an amateur use cellular technologies with SDR?
Software Defined Radio is opening up many new possibilities for amateur digital modes. One family of technologies that interests me is cellular. 2G GSM voice/sms and 2.5G GPRS data has been proven to work with OpenBTS on a USRP SDR using licensed…
JC Hulce
- 901
- 5
- 16
11
votes
1 answer
Tuning a wire antenna by folding
Last weekend we tuned a quad loop for 80 m and 40 m. Instead of cropping, we folded the isolated wire using cable ties as shown in the picture below.
After folding several quite large sections of the wire, we got the SWR under 1.2, so this approach…
koalo
- 399
- 1
- 10
11
votes
2 answers
How do I renew my FCC amateur license?
I have a technician class license, and my license expires in March 2014. How do I renew my license?
I received a notification in the mail from W5YI-VEC informing me that I could renew my license through them. They included a form that I can fill…
Ben Miller
- 221
- 2
- 8
11
votes
4 answers
How does VHF/UHF propagate beyond the expected (radio) horizon?
I am not asking about the fairly well-known effect of the earth "appearing less curved to radio waves" that are otherwise still essentially line-of-sight, but a deeper arcanum:
In the ARRL Antenna Book, 17th edition (1994) there is a discussion of…
natevw - AF7TB
- 7,529
- 3
- 29
- 63
11
votes
3 answers
Could a weather balloon make a good antenna?
I can't afford a massive tower, but I can get a weather balloon. What kind of set up would work best to get the maximum efficiency out of altitude?
Muze
- 1
- 3
- 11
11
votes
4 answers
Single or Dual Paddle Key?
I want to eventually use a CW paddle and built in keyer in my Yaesu FT-890. What are the merits of each style. Single or Dual Paddle. Does it make any difference if I start with say a dual paddle then later use a single paddle? Any disadvantages of…
jim
- 161
- 1
- 5
11
votes
2 answers
How to reduce RF in the shack when using vertical HF antenna (no radials)
What can be done to reduce RF in the shack (riding back along the coax) when using a vertical 10M antenna (without radials due to space constraints)? The antenna is an IMax-2000 at 32' elevation (20' over roof) with a 125' coax LMR-400, SWR is under…
Ron J. KD2EQS
- 1,290
- 1
- 12
- 25
11
votes
3 answers
Are hashes (such as md5) legal in the US
If I were to implement a remote computer control system using amateur radio, would using hashes (such as md5, sha-*, etc...) for authentication be permissible under the United States rules?
W8AWT
- 1,346
- 2
- 13
- 32
11
votes
6 answers
What transfer rates are actually achievable using known digital modes?
I've found all sorts of info concerning digital modes, sound samples, spectrum samples, but nobody ever cites what speed a given digital mode can reach.
Could anyone tell me more about that, or point me somewhere where I can find this kind of info,…
red-o-alf
- 303
- 2
- 11
11
votes
4 answers
Is there a convention for SSB frequency selection?
I know that the amateur bands are not channelized. I know that anyone can pick an arbitrary frequency and they're not wrong, and you are not obligated to have a calibrated VFO. But if everyone picks frequencies at random during a period of heavy…
Kevin Reid AG6YO
- 25,080
- 7
- 55
- 106