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1500 questions
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
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
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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
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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
- 4
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
- 163
- 3
6
votes
2 answers
Base vs center loading a vertical antenna
I currently use a homebrew 40/60/80m vertical consisting of a 5M aluminium tube with a multi tapped coil at the base. The ground plane is the metal roof at my house, and the antenna is not centered in it, but it's next to one of the edges.
I read…
hjf
- 1,209
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6
votes
3 answers
Cheap antenna for new HF HAM
I just got a 100W HF radio and I am new at this. What is the cheapest antenna I can hook up without burning up my radio or shocking myself?
Pugz
- 161
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6
votes
2 answers
Can an ultra-wideband system transfer data at high speed without precise clock synchronization?
Recently, ultra-wideband technology has been in the news again. From the Wikipedia article:
UWB transmissions transmit information by generating radio energy at specific time intervals and occupying a large bandwidth, thus enabling pulse-position…
natevw - AF7TB
- 7,529
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6
votes
1 answer
How do I evaluate and use a toroidial core for my HF double-balanced mixer?
Last year, I planned to make a double-balanced mixer covering the entire 3-30 MHz band as an upconverter for my RTL-SDR receiver, mainly for learning RF circuits and ham radio. Naturally, it requires two RF transformers as baluns, possible 4:1 or…
比尔盖子
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6
votes
3 answers
How can I decode SSTV with only macOS software?
Have you used an SSTV decoding application on an up-to-date version of macOS? Which one, and if you built from source, can you share the steps you took to do so?
I do not know of a single working macOS application for SSTV decoding. I've been…
Amin Shah Gilani
- 892
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6
votes
1 answer
Can tropospheric scatter effect be used by 802.11 links?
What are the lowest EIRP and antenna gain requirements that make possible use of troposcatter at the distances of 100 to 150 kilometers assuming conventional WiFi (6 Mbit/s data rate with OFDM/BPSK modulation)?
While this is unlikely to work in…
Deer Hunter
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6
votes
2 answers
GnuRadio RF transmission, legal and safety issues
I'm trying to run some transmit/receive RF examples that I found online using GNU Radio with USRP B200. I read and heard about some cautions in terms of transmitted frequencies here in the USA which made me slow down! What is the legal frequency…
Hadad
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6
votes
1 answer
Kenwood TH-D72A: what's the difference between Tone and CTCSS?
Kenwood TH-D72A supports 3 types of tone: Tone, CTCSS and DCS.
What is the difference between Tone and CTCSS?
As far as I know CTCSS is basically a continuous transmission of a given low frequency signal mixed with the voice. So it's basically a…
Aleksander Alekseev - R2AUK
- 4,307
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6
votes
3 answers
Can I take and use Baofeng UV-82 in Norway?
Planning to go for a camping trip. According to this document (in Norwegian but easy to understand), I can use a radio running PMR446 and KDR 444 freqs. Baofeng can do this.
The question is: is the Baofeng unit legal itself? And is it legal to take…
Alexander
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