Radio station CHU in Ottawa, Canada broadcasts standard time and frequency references on three shortwave radio frequencies, 24 hours a day. CHU transmits using amplitude modulation (AM) consisting of an RF carrier and a single upper sideband containing audio information. The beginning of each second is represented by a tone burst having an audio frequency of exactly 1000 Hz. In this video, two minutes of CHU audio are plotted on the Y-axis, while a local 1000 Hz sinusoidal reference is plotted on the X-axis, thereby producing a Lissajous pattern. The 1000 Hz reference is derived from WWVB’s 60 kHz carrier, and in this application is accurate to less than one part per billion. We would expect to see the 1000 Hz tone bursts from CHU produce a stationary pattern if the received frequency of the tones measured exactly 1000 Hz. What we see, however, is a slowly rotating ellipse, especially in and around the time of deep signal fades. This rotation is indicative of a shift in phase that is taking place over time. A change in signal phase over time implies that a change in frequency is also taking place. Since the audio recovered from the receiver is a product of the received carrier and upper sideband frequencies, it can be concluded from this exercise that the carrier and sideband signals are undergoing separate and distinct changes in path length, Doppler shift, polarization, and/or multipath propagation effects, even though they originated from a single transmitter, and are …
Ten-Tec T-1253 kit ( radio.tentec.com ) receiving Morse code on 80 meter amateur radio band, frequency 3552 kHz. Video shows operation of regeration control used to demodulate CW (continuous wave) signals. Annotation of CW message is included.
Product DescriptionMade by the same manufacturer that makes brand name radios, such as Grundig, Eton and etc. The Tecsun PL600 is an AM/FM/LW shortwave radio with Single Side Band (SSB) reception.
There are four options when tuning your radio stations. With direct tuning, you input the desired frequency digits. Manual tuning allows you to change the frequency using the tuning knob. If you are unsure of what station you want, use the scan tuning option to have the radio stop at all h. . . More >>
PLL digital tuner receives FM, MW/AM, SSB, shortwave and longwave
MY-memory tuning memorizes and scans up to 100 frequencies
Four tuning methods: direct, manual, scan and preset
World clock and dual clock functions; built-in timer
Label presets with 6 alphanumeric letters
Product DescriptionAM (LW / MW / SW) and FM stereo reception / 10-key shortcut adjustment / Dual Alarm Clock World Clock / 100 presetsAmazon memory of the station. The CMO DescriptionThe Sony ICF - SW7600GR band world receiver radio will keep you connected to FM in the morning, there is a digital PLL tuner shortwave and longwave radio. With the single sideband (SSB) reception, will launch the smallest amount of radio interference. To further enhance the pleasure of hearing, the synchronization of Germany. . . "More Information"
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