night effect


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Related to night effect: Automatic direction finder

night effect

[′nīt i‚fekt]
(navigation)

night effect

night effect
The effect of changed polarization on a direction finder occurring at night. The effective range of a long-range beacon that has a daytime range of 200 NM may be reduced to about 70 NM by night. This reduction in range occurs because of the presence of sky wave propagation in an LF/MF (low- and medium-frequency) band. The sky wave is not present during the daytime, but at night the sky waves affect the ADF (automatic direction finder) accuracy. The change in polarization in radio waves refracted by ionospheric layers results in a signal voltage being induced in the horizontal positions of the loop antenna, causing erroneous bearing directions. The effect is most common at night.
References in periodicals archive ?
Martin et al., "First night effect in different forms of Schizophrenia (Pilot investigation)," Dynamic Psychiatry, vol.
In-laboratory PSG studies are associated with a phenomenon known as "the first night effect".
Finally, analysis of covariance (controlling for age) was used to examine differences in sleep for both reason for hospitalization and first night effect.
Shuker is confident the Friday night effect at Prenton Park can help Rovers pull off a second win of the week against unpredictable mid-table Bradford.
The "First Night Effect" when trying to sleep in an unfamiliar environment and the "On-Call Effect" caused by anxiety over a wake-up call, hallway noise or other concern.
This finding is also in line with previous investigations of our group, which showed an absence of the first night effect in schizophrenic patients with predominantly negative symptoms (Rotenberg et al., 1998).
Quite apart from the Last Night effect, attendances were well up on last year.
This study used this "first night effect" to produce a laboratory model of occasional (transient) insomnia.
Moore hopes the Friday night effect can help Rovers sustain the momentum of a strong start to the season when they play host to Bristol City at the weekend.
The "first night effect" results from sleeping in an unfamiliar environment,[35] and if this effect increased the likelihood that subjects had a worse-than-usual first night's sleep in the laboratory, this bias could have acted to spuriously increase the magnitude of benefit seen from treatment.