Questions tagged [fm]
Questions about Frequency Modulation, the analog modulation scheme commonly used for voice on VHF and UHF frequencies.
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Gap between a dipole antenna
I need to know how much gap should be there between the two arms of a dipole antenna?
I would also like to know how much gap is there between the two rabbit ears antenna and is the loop antenna ...
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How an Audio Signal is Modulated with FM?
An audio signal can have varying frequency and amplitude and both are the part of the information. But as per my knowledge , Frequency modulation is a technique where the frequency of the carrier wave ...
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Natural dipole / monopole filtering
Word has it these antennas are broadband, however my calculations show one may not need FM / AM BCB wave traps if not operating around those frequencies.
I have run the script here for:
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Does an FM Loop Antenna's Loop diameter affect reception?
I live 75 miles from one of my favorite station's broadcast tower (91.1 FM), and I would like to get better reception.
Currently, I am using a NAD 4150 Tuner with a T style antenna. I ran it out a ...
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Why can I connect simplex at 146.52 but not at 145.200 and 147.000? [closed]
I am preparing myself to use Winlink.
I am preparing myself to use VARA FM.
145.000 is the Simplex frequency used by our local university (Montana State). It can be used for both voice and digital, ...
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Can I use a generic FM 2m radio for meteor scatter or other digi modes?
Firstly, I know it’s possible, but is there any actual activity for 2m MS. I want to get into Meteor scatter but i am wondering if i can use my 2m FM transmitter with a TNC and a yagi for meteor ...
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High SWR at full height
I operate a low power FM radio station. I have always had issues with high SWRs. Recently I have purchased a new transmitter, new antenna, and new 100 ft cable from the same company assuming they ...
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2m FM: where do I actually QSY to after establishing contact on 145.500?
I am new to amateur VHF, coming from HF and marine.
Online advice says after establishing contact on 145.500 then QSY. What is the range of channels/frequencies most folks use? ie that they are ...
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How to use GNU Radio to demonstrate FM demodulation without baseband signals
Using GNU Radio, I'm currently trying to create a flow graph containing a simple demonstration of how FM modulation and demodulation works. Since the target audience is not accustomed with complex ...
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Is FM effectively spread spectrum?
My understanding is that FM achieves better audio quality (under the right circumstances) than AM by spreading the narrow audio signal's information into a wider RF signal. Does this mean FM is ...
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Would it be possible for a software-defined FM receiver to demodulate two signals on the same frequency?
When two FM signals are transmitted on the same (or about the same) center frequency, either you hear only one or you hear that noise I'm sure most of you have heard. Would it be possible for a ...
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Looking for an inexpensive FM downconverter for an SDR project
I do a lot of work with DSP and I am looking for an inexpensive down converter so as to down convert from the FM band to some intermediate frequency. Not necessarily to standard FM 10.7MHz but ...
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How does injecting a carrier allow a FM receiver to demodulate SSB?
I just watched VK3YE's video on demodulating SSB using a FM receiver. (https://www.youtube.com/watch?v=kJ-cj-YwflY)
In the video, he demonstrates that by transmitting a very weak CW carrier, the FM ...
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Mini-Din 9600 Deviation Measurement
In an ongoing testing effort to get the highest speeds from VARA-FM, I have been examining the characteristics of the "9600 baud" 6-pin mini-din input on my Icom-7100. Although there is only ...
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Is SSB and FM voice considered TDD or FDD (and what are TDD/FDD)?
We are looking at the Qorvo QPL9547 LNA and the datasheet notes:
For TDD Applications: R1 = 0Ω & R2 = 100K
For FDD Applications: R2 = 100K ‘OR’ Pin 6 tied to ground. R1 = DNP/Omitted
This will ...
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