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

2
votes
0answers
33 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 ...
2
votes
3answers
93 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 ...
4
votes
2answers
81 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 ...
5
votes
1answer
79 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 ...
3
votes
3answers
215 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 ...
3
votes
2answers
87 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). ...
2
votes
1answer
131 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 GnuRadio. Now, I would like to measure performances of my receiver. For this purposes I did following: I ...
1
vote
1answer
79 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 ...
12
votes
3answers
2k 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 ...
23
votes
4answers
21k 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 ...
8
votes
1answer
1k 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 ...