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Questions tagged [snr]

Signal to Noise Ratio - any questions about improving or detecting an SNR or lowering your noise floor.

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What would the Signal to noise ratio be for SSB under normally (just) readable conditions?

I want to estimate an upper limit for the data that can be sent over single side band. The upper limit can be determined using Shannon-Hartley theory. The Shannon-Hartley theorem is given by: $$C = B \...
Mr Purple's user avatar
  • 101
1 vote
0 answers
61 views

What is the point of using LNA if the SDR can increase the gain itself [duplicate]

Usually there is a LNA next to antenna, while SDR devices also have gain setting so we can increase the gain. As i know LNAs are amplifying all signals with same gain (Am I right?) So i wonder what is ...
Ariyan's user avatar
  • 143
6 votes
1 answer
391 views

SNR measurement for a BPSK/QPSK signal

I have created a software (gnuradio) that performs modulation/demodulation and supports a number of modulation schemes and error correcting codes. I'm in the process of evaluating the BER vs SNR for ...
Moses Browne Mwakyanjala's user avatar
3 votes
3 answers
216 views

Are there any terrestrial timecode signals receivable in Boston Massachusetts?

I'm looking for any timecode station (like WWV/B, CHU, etc.) with an SNR > 0 dB that I should be able to receive in Boston Mass. WWVB at 60 kHz has a phase modulation that one can apparently receive ...
Martin Klingensmith's user avatar
4 votes
2 answers
305 views

Use noise figure and gain to calculate weakest signal radio can receive?

An FM radio receiver, using a 1 kHz tone at 3 kHz deviation has a 12 dB SINAD (Signal To Noise and Distortion) of -116 dBm. I would like to increase the 12 dB SINAD sensitivity of the receiver to at ...
Skyler 440's user avatar
  • 7,620
4 votes
1 answer
167 views

Is the error rate for QPSK31 in a white noise channel worse than BPSK31?

I've read in a couple sources that in a channel consisting of only additive white Gaussian noise (AWGN), at low SNR, QPSK31 is actually worse than BPSK31. http://www.arrl.org/psk31-spec, probably ...
Phil Frost - W8II's user avatar
5 votes
3 answers
544 views

How big is a decibel?

Say I've calculated that my feedline losses are 3dB, or I'm considering an antenna with 10dB gain, or trying to decide between a transmitter with 10dBm output power versus 16dBm (6dB difference). I ...
Phil Frost - W8II's user avatar
3 votes
2 answers
102 views

Link margin calculations with two antennas and two low noise preamplifiers

Background - UHF - 434-438MHz Two identical crossed Yagi's mounted on rotator. Currently, I have a low noise preamplifier after combining cables from the two antennas (T connector + matching stub). ...
user80551's user avatar
  • 201
2 votes
1 answer
196 views

FSK real world application BER

I have designed a receiver for FSK reception in 434 MHz ISM band. For this I used USRP1 and GNU Radio. Now, I would like to measure performances of my receiver. For this purposes I did following: I ...
Nexy_sm's user avatar
  • 241
2 votes
1 answer
123 views

Preferred signal report format for Digital Voice?

When using FreeDV or other digital voice modes, what's the preferred signal report? The software has a single SNR number, but that fluctuates quickly. Since it's a digital mode, you either get the ...
scruss's user avatar
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15 votes
4 answers
6k views

Is a vertical noisier than a dipole, and if so, why?

I've had people tell me, anecdotally, that a vertical is noisier than a dipole. Is this true, and if so, why? If it is true: Is this additional noise, such that SNR is degraded, or is the vertical ...
Phil Frost - W8II's user avatar
31 votes
6 answers
41k views

Can I reduce RFI/noise at the antenna?

Recently, the power was out in my neighborhood for an extended period of time. I fired up my HF rig using battery power and was amazed at the lack of noise across the HF bands. When the power grid ...
The Driver's user avatar
9 votes
1 answer
2k views

Digital-mode signal reports

When operating analog voice, we give a qualitative (or possibly just arbitrary) signal report, 'scoring' the signal either out of a maximum 'five by five', or a maximum '599'. How do you report the ...
Dan KD2EE's user avatar
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