What was the first longwave radio receiver built for the Navy?

The RAA receivers were the first longwave superheterodynes built for the Navy. Even though produced during the depths of the Great Depression, RCA’s extravagance when designing for the Navy is evidenced by the RAA.

How many valves are in a radio receiver?

The receiver has 10 valves of which 3 are for the D/F and one is a Tuning Indicator (magic eye). There are 6 used for the super heterodyne receiver. The receiver has an RF stage, a mixer/oscillator, two IF stages, an AVC and BFO stage, a detector, an audio amplifier, and a magic eye tuning indicator.

What is the last position on a radio?

The last position is a “FIGURE-OF-EIGHT” position (shown on the front panel as the number eight symbol) and this uses the loop aerial only, to determine transmitter direction, the 8 representing the loop aerial pattern.

Why does my Denon AV receiver keep shutting off?

I disconnected all the speakers and peripherals, even the subwoofer, but it still keeps shutting off. Sometimes it works perfectly, all audio channels crisp and present, for a week or more at a time before it shuts off. Sometimes it shuts off within a couple minutes over and over for days on end every time I try.

How is resistance tuning carried out on a VLF-LF receiver?

Tuning is carried out by a potentiometer, the resistance of which sets the frequency of the heterodyne oscillator. The RF end is untuned and the receiver bandwidth is set by two inexpensive ceramic filters in the IF channel. All inductive elements are provided by stock lines of miniature RF chokes.

What is the range of a superheterodyne LF receiver?

The superheterodyne receiver described is the result. It has been designated a VLF-LF receiver, because it tunes the VLF-LF range from 10 to 300 kHz, but it also tunes part of the MF spectrum from 300 to 500 kHz. The VLF and LF bands have their own unique useful characteristics and these will be discussed further on.

Why do LF antennas have low radiation resistance?

Due to the long wavelengths in the band, nearly all LF antennas are electrically short, shorter than one quarter of the radiated wavelength, so their low radiation resistance makes them inefficient, requiring very low resistance grounds and conductors to avoid dissipating transmitter power.

Is the lf353 package used for RF amplification?

One LF353 package is used for RF amplification and one and a half LF353 for IF amplification. The remaining odd half is used as an audio driver following detection. The RF Circuit