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1500 questions
4
votes
2 answers
Very odd and wide 30m signal. What is it?
A local ham friend copied this strange, wide signal on 30 meters on his Flex 5000. Anybody know what it might be?
Mike Waters
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4
votes
1 answer
What are the best APRS SmartBeaconing™ settings for different modes of transit?
There are a variety of websites that give sample SmartBeaconing™ settings – mostly for automobiles, but some for bicycles and pedestrians. I've tried several of these settings and had mixed results. Can anyone share a set of…
Rafael KR7MJ
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4
votes
1 answer
ISS APRS Digipeater with Kam XL and ICOM IC-910H
I am trying to use the ISS APRS digipeater which transmits at 437.55MHz.
Hardware setup consists of the following
ICOM IC-910H.
The transceiver has been connected to a Windows PC running a HAM deluxe software package called Satellites. Basically,…
Moses Browne Mwakyanjala
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4
votes
2 answers
Linux based SDR spectrum capture via CLI
I need to setup a Linux box to run unattended capture of about 10 MHz - contiguous worth of spectrum (Hardware must support between 500 kHz and 200 MHz) targeting voice (mix of AM and FM voice broadcasts), and another process to selectively…
jbrown
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4
votes
1 answer
How large should the call of the remote station be on the QSL card?
I have designed my first QSL card but I'm worried that I may have reserved too little space for the call of the remote station. I'm worried that the buro might have trouble with it. However, I see many QSL cards on this examples page with a fairly…
user885
4
votes
5 answers
Can a Baofeng UV5R receive airport radio transmissions?
I have tried programming approach frequencies into my baofeng and cannot hear any transmissions. Freq programming was done using a desktop computer connected to the radio to frequency 121.9MHZ. Nothing was heard, just standard background static. …
jason97m
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4
votes
1 answer
Signal Source Block of GNU Radio
GNU Radio has a Signal Source Block which considers a set of variables to produce an output, namely sample rate, frequency and amplitude.
In signal processing, we define a basic waveform by its frequency, number of samples within the period and its…
Denis
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4
votes
1 answer
How do repeaters work? (The technical side)
I'm curious how AM and FM repeaters work.
Is the received signal demodulated and then remodulated at the new frequency or do they use some other technique?
vini_i
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4
votes
2 answers
What does the FCC do with confiscated equipment?
When a station is repeatedly violating FCC rules, transmitting out of band etc, equipment may be confiscated in addition to the fine. I am sure they have collected a large chunk of inventory from violating hams, pirate radio stations, kilowatt CB…
Skyler 440
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4
votes
0 answers
OFDM spectrum, HACKRF, and GNUradio companion
I am trying to analyze the spectrum of wifi spectrum.
I getting a good OFDM spectrum with my HackRF at 2.412 GHz (from my first QTGUI Sink).
But I get nothing out of OFDM Receiver. I was wondering why. Any help would be appreciated.
Jack
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4
votes
1 answer
How many frequency channels are there in a frequency band?
I've often heard people saying that 4G uses the 1800 MHz band but precisely what all frequencies does it work upon? Does it mean that is just uses one frequency i.e. 1800 MHz, well in that case wouldn't there be interference among signals carrying…
Shivam Aggarwal
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4
votes
1 answer
SDR with the Raspberry Pi
I wanted to explore digital modes by connecting a Raspberry Pi via audio cables to a transceiver. However, I realized that thanks to the clock generator, the raspberry pi can produce RF signals directly. Adding a square to sine wave converter, a…
Edgar H
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4
votes
1 answer
Steel Directors with Copper DE
I found old plans for a quagi that uses copper for the Reflector and Driven Element and any 1/8" metal available for the directors. The general recommendation for antennas is: no steel for the DE. Is it OK to use for the directors, and OK to 'mix'…
Mein Tenah
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4
votes
4 answers
Why does an "electrically small" antenna have narrow bandwidth?
Reading this interesting piece on magnetic loop antennas, the author explains that a magnetic loop has great efficiency even at small size, but the the price you pay is very narrow bandwidth. Why is this?
It seems counter-intuitive (and miraculous)…
bcattle
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4
votes
2 answers
How to determine a serial number in cq contest?
What serial number is referred to in a cq contest? How do I determine that serial number?
Louis Stannard
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