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Questions tagged [testing]

Techniques for testing the functionality of radios and other equipment. Do not use this tag for license examinations; use [license] instead.

13
votes
3answers
252 views

WWV, WWVH, and WWVL may be shut down. Are there any alternatives?

The US government is proposing to shut down the NIST standard time and frequency stations WWV, WWVH, and WWVB in Colorado and Hawaii. If that actually happens, are there any free or inexpensive ...
7
votes
2answers
130 views

How did hams manage to tune their antennas before VSWR meters?

In the early 20th century --back when the hobby was still new-- before VSWR meters and antenna analyzers were invented, how did radio operators know whether they were tuned for maximum power out? ...
2
votes
0answers
39 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 ...
5
votes
3answers
657 views

Cause of harmonic spurs?

Harmonic spurs (harmonics of the transmitter frequency, as seen by a wide-band receiver or SDR) in the RF spectrum might be caused by an imperfectly sinusoidal or badly filtered transmitter carrier ...
3
votes
1answer
90 views

RF fading channel model?

What statistical or other descriptions exist regarding modeling of an HF-band RF fading channel? This is allow making (as in code my own software) lots of simulated test input signals for an SDR ...
0
votes
2answers
94 views

Testing Radios Back-to-Back without Going Over-the-Air

Is there a device, something like a dummy load, that will allow one to test two radio's back-to-back without going over the air?
3
votes
1answer
164 views

Would a switched RF attenuator be (a)symmetric?

I picked up this 0-80 dB switched RF attenuator at a flea market, with no part number or other useful markings other than the knob settings. I've tested it and confirmed that it works, but there's one ...
6
votes
1answer
230 views

Regenerative receiver interference?

Can a regenerative shortwave receiver (especially an old vintage unshielded tube or transistor model) connected to a wire antenna generate HF interference? If so, what are some ways to prevent one ...
1
vote
2answers
109 views

ID station when testing an oscillator or transmitter into a dummy load?

Should one always identify ones station (say via CW keying) when building/testing an HF oscillator and/or anything that could amplify that oscillator, when powering the circuit on a breadboard and ...
3
votes
2answers
191 views

Which frequencies in a band should I use for antenna and radio testing?

Are there any frequencies (HF, 2m and 440) that are more suitable than others (assuming all are within those licensed to the operator) for testing new radios and/or antennas? I assume that one should ...
6
votes
4answers
4k views

Operating proceedures: testing an HT against a repeater?

Assuming proper licensing for the frequency, what is the proper operating procedure to test whether an HT works and is within range of a (documented as open, 2M or 440) club repeater? Should one wait ...
12
votes
1answer
5k views

How to detect common-mode currents or “RF in the shack”?

Let's say we already know that if your antenna is not suitably constructed or connected then you can get current on the shield of your coaxial feed line which will flow through the shielding/grounding ...
2
votes
2answers
1k views

Simplest, smallest antenna for tuning WWV, WWVH?

I'd like to perform some simple receiver testing and calibration (mostly for frequency variance, not signal strength) and have been told WWV/WWVH transmissions can be found throughout most of the US. ...
4
votes
3answers
1k views

Are there any good, consistently receivable signals in the US for HF receiver testing?

Having built my first HF receiver, I'd like to know if I'll need to search around for transmissions that happen to be occurring, or if there are reasonably strong signals I can count on being present ...