Mini Receiver

FB7-NX - National RF, Inc

In about 1935, the National Radio Company of Malden, Mass., brought out a “hot” high frequency receiver, called the FB7, and the subsequent FB-7X. It featured a super-hetrodyne design with plug-in coils that gave it a broad frequency range. The “X” model also incorporated a crystal filter in the intermediate frequency section, thus giving it additional selectivity. The receiver was viewed by radio amateurs as a technological breakthrough, and it was also used commercially for point to point high frequency communications. As the receiver did not have an internal RF amplifier section, a separately tunable RF amplifier was later provided in a separate enclosure for additional performance capabilities. Now, National RF, Inc., is resurrecting the fabled receiver name with an all solid-state, hot mini receiver, which also utilizes plug-in coils to cover the HF spectrum. The mini-receiver is designed for use by radio amateurs as well as serious short-wave listeners, and allows reception of AM, CW, and SSB signals. It incorporates a super-hetrodyne design with a dual gate FET built-in RF preamplifier and a ceramic filter for selectivity, often required when used in a crowded amateur radio band. In addition, the receiver has a buffered rear panel output of the high frequency oscillator for use with either a frequency counter for exact receive frequency display, or for interface with an outboard transmitter. A rear panel jack is also provided for muting the receiver when a transmitter is placed into the transmit mode. And, the receiver is small enough to fit into carry-on luggage and taken on trips when it is desired to “keep an ear” on amateur radio or other high frequency activity. The receiver utilizes rear panel plug-in coil assemblies which contain the RF amplifier, mixer, and oscillator tuned circuits. Each plug-in coil assembly also comes with a separate dial scale, which is inserted onto the front panel for displaying the tuned frequency. A very smooth 6 to 1 planetary drive is used for tuning the receiver. Other front panel controls include RF preamplifier peak, volume control, Beat Frequency Oscillator adjustment, and RF gain control. Other switches include filter bandwidth, AM/CW/SSB selection, Power, and a general coverage/band spread control for certain plug-in assemblies. The receiver is intended to drive head-phones via a rear panel jack, but has sufficient output to drive a small external speaker.