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Which is the lowest carrier frequency for AM radio?
Footnote 1: The wavelengths of AM radio signals vary from a maximum of 555 meters (1821 feet) at 540 kilohertz (kHz), the lowest AM carrier frequency used in the United States for broadcast stations, to a minimum of 176 meters (579 feet) at 1700 kHz, the highest carrier frequency at the upper end of the AM expanded band.
What is the range of a HF radio?
The HF band is defined as the frequency range of 3 to 30 MHz. In practice, most HF radios use the spectrum from 1.6 to 30 MHz. Most long haul communications in this band take place between 4 and 18 MHz.
How big is a 20 meter AM transmitter?
The result is a 40 and 80 meter 20 watt high level plate modulated AM transmitter. It uses a pair of 6L6GC tubes in Class AB1 push-pull generating between 15 and 20 watts of audio power, high level plate and screen modulating a 6146.
What kind of AM transmitter do I Need?
For years I used a WRL Globe Scout 680 on the 20 and 40 meter AM windows. This Novice rig from the 50s works fine, but it does leave something to be desired in the modulation department. It uses Heising modulation, and is only able to do at best 80% modulation.
Sound transmission losses of partitions and floors are also influenced by stiffness. Transmission loss graphs for stiff materials show dips in particular frequency ranges where the sound transmission losses are reduced below those expected from mass law. This is called the coincidence effect and often leads to a reduced STC rating.
How to measure the airborne sound transmission loss?
In Chapter 9 we discussed the formal procedures for the measurement of the airborne sound transmission loss and the determination of the Sound Transmission Class (STC) of a partition.
How does mass law affect sound transmission loss?
The mass law equation predicts that each time the frequency of measurement or the mass per unit area of a single layer wall is doubled, the transmission loss increases by about 6 dB. To increase the sound transmission loss of a partition by 12 dB at all frequencies, therefore,…