Amateur Radio Stack Exchange
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1500 questions
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2 answers

Software defined radio demodulation

I am trying to increase my knowledge on software defined radio and according to what I have read its hardware consists of three parts: Amplifier Tuner ADC I just wanted to make sure that my assumption that the filtering and demodulation is done…
Jack
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If EM waves require no medium, why can't I get service at all times?

I have taken two years of high school physics and am very interested in RF communication. I know that electromagnetic waves do not necessitate a medium in order to propagate. Thus, shouldn't I be able to send/receive RF signals even when the signal…
MikeE
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CW "training" recordings

I'd like to get some recordings of typical receiver audio output of HF CW transmissions. I'd like to both train my mental copying capabilities and look into improved automatic (software) CW transcribers; hence, typical, humanly induced symbol rate…
Marcus Müller
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Where year 2016 falls in the sun spot cycle for HF propagation?

Are we now at the good or bad portion of the 11 years cycle? What effect are we seeing now? How large (strong/deep) is the effect during the peak and bottom of cycle? What will change in coming years?
EEd
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BFSK with huge spacing, why?

I recently bought one of the classic USB dongles to experiment with SDR. At 460MHz (Europe, CH) I constantly see many digital transmission that use BFSK. What is strange to me is that: the frequency spacing is about 9KHz, instead of the much lower…
MarcoM
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How Are US Call Sign Location ID's Assigned?

If I take my license exam in California, but my residence is in New York, would my call sign still reflect the New York location?
user7822
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4 answers

Recommended way to analyze spectrum output of a high-power amplifier?

I have a small collection of "software defined RF lab" equipment, notably a HackRF and a VNWA3. I am almost done building a 35W HF amplifier and once I've done some other testing, would like to look at the spectrum of the final output as a…
natevw - AF7TB
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Convert maidenhead grid square to lat/long in Excel?

I have a list of maidenhead grid squares in an Excel sheet that I want to convert to latitude and longitude. I want to keep it as simple as possible. Does anyone know of a formula to convert from maidenhead to lat/long?
user6587
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Use ham to broadcast GPS RTK correction data

I am involved in a precise positioning project that uses Real Time Kinematic (RTK) for cm-accurate positioning. We use unattended base stations that provide real-time corrections for mobile rovers. The corrections can be used within a radius of…
Kozuch
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How can I know whether a radio is FCC approved?

I'm considering buying a new HT radio (Hong Ying HX-860UV Handheld) from China. The company says the model is approved by the FCC. Since I can't see it in person (only a photograph), I can't confirm. How can I be sure they are telling the truth?
W D Patterson
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Squelch never seems to "open the gate" on Wouxun KG-UV9D

I just got my Technician's license a few weeks ago and I'm trying to figure out if this is user error or if I need to return my radio. My understanding of squelch is that when the received signal strength exceeds the squelch threshold the radio…
Matt KI7CMZ
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Amateur Radio for a Nomad

I got my amateur license back in the early '80s, primarily for putting it on my resume for an electronics job. Never used it outside of developing my Morse code speed, and once I got my Advanced Class and short call sign, I never used it again. Well…
KiloVoltaire
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What are the legal requirements for an amateur radio satellite?

Lets say I can throw a satellite into orbit (I've got a good arm). I'm amateur radio qualified so can I just set it up to transmit on an amateur band and start having fun? Is there anyone I have to register with? Or am I good to go with my own…
FraserOfSmeg
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Incoming angle of radio signal reflected off of ionosphere

I am about 870 miles and 16 degrees due west of WWVB at Ft. Collins, CO. WWVB transmits at a frequency of 60 KHz. At this distance I should be getting the signal reflected from the ionosphere. If I assume the ionosphere layer I'm getting the bounce…
BillDOe
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Necessary spacing for 1 kW Gamma Match on 144 MHz

I'm working on a 144 MHz antenna using a gamma match. The best result (resonance 50+j0 at 144.400 MHz) I reached is a 10 mm diameter gamma rod, 15 cm long and a capacity of 10 pF. I thought to obtain the 10 pF with a 4 mm rod inside the gamma rod…
Kevin White
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