National RF, Inc
National RF Inc offers State of the Art Radio Frequency and Unique Electronic Devices
- 858-565-1319
- 858-571-5909
- 7969 Engineer Road
Ste. 102
San Diego, CA 92111
Categories
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Vector Finders with InternalAttenuators
VF-145 LA AND VF-145 LMA
The VF-145 LA and LMA models are functionally the same as the VF-145 L and LM on both electrical performance and mechanical specifications. However, the LA and LMA models include an internal PIN diode attenuator that provides up to 12 dB of attenuation (measured at 150 MHz, attenuation decrease slightly as operating frequency increases) to the incoming radio signal. This attenuation occurs after the signal is received by the unit and phase shifted for processing, but before it is placed on the coax feedline to the receiver. In addition, the PIN diode utilized will absorb short burst of RF should transceivers be keyed accidentally by the user. This feature aids in very strong signal DF operations but will not totally guarantee against system overload under very strong RF emissions.
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ELT STALKER Vector-finder
VF-121
The Vector-Finder Types VF-121 and VF 121A are unique in the Vector-finder series of direction finding antennas. They incorporate a proven design, electro statically shielded loop sensing element with modern solid state low noise analog and digital technology to allow detection and location of aircraft band signals. Both the VF-121 and the VF 121A incorporate a unique digital modulator which allows the user to more easily home-in on unmodulated carriers. Such cases occur at airports when transmitter may be accidentally keyed on during aircraft overnight layovers. The VF-121 is specifically designed to be used on airport premises where signal strengths are high. To compensate for very strong signals, an integral attenuator is also incorporated to allow the user to operate the unit close-in to aircraft. The VF-121A differs in that a high gain, low-noise preamplifier is utilized with the sensing element in order to hunt signals that may be weak or at a distance. The unit is ideally suited for the location of ELT transmitters in the field. Both units are tunable over the 118 MHz to 130 MHz aircraft frequencies and interface directly to the user’s aircraft band receiver or transceiver via the antenna jack. With the antenna system connected to the receiver, the user will hear the desired signal. If the signal is unmodulated, the digital modulator will generate a tone on the carrier. When the handheld unit is rotated about, an audible null on the received signal or the generated tone will be heard. This null aligns with the axis of the equipment case and represents the direction of the received signal. This direction may be read from the black dial compass mounted on the top of the enclosure. As the response is bi-directional, triangulation may be used to determine the true bearing when the true direction is not known.
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Reference Antennas
Type NRD
Reference antennas are precision dipole antennas that offer a fixed 2.15 dB of gain over an isotropic antenna along the major lobe axis at specified frequencies (2.15 dBi). They are intended to be used for antenna field pattern and gain measurements, or general RF sensing in the laboratory.
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RF Proximity Detector
Type RPD-2 AND Type RPD-2A
The Type RPD-2 Radio Frequency (RF) Proximity Detector is designed to detect and locate devices that radiate radio waves in the high frequency to low microwave frequency range. Such devices often include surveillance and “spy” equipment. The Type RPD-2, when used with the different sensors, will detect the emanation of the radio wave within a confined area, and then isolate its location to within approximately a square foot. The type RPD-2A may be used as an RF field strength indicator for antenna field strength measurements. The RPD-2A is identical in function except that the meter scale is calibrated in relative dB units.
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Analog Power Supply
Type NPS-2412
National RF's Type NPS-2412 analog power supply was designed to be used in communication equipment where radiated switching inverter noise from conventional “switching type” supplies is not acceptable. The power supply consists of a standard rectified transformer output driving a pair of voltage regulators and filtering networks. The 2412 offers an adjustable voltage output between 2 and 24 volts as well as a fixed voltage output of 12 volts. A maximum of 20 Watts of DC power can be supplied from the unit. As the voltage regulators dissipate power in the regulation process, the power to the load is derated accordingly, dependent on the set voltage to the load. The adjustable regulator is a standard LM-317T integrated circuit device. The fixed regulator is a standard LM 7812 device. Upon customer request, the LM 7812 device may be changed to any voltage rating within the the LM-78xx series of regulators. Contact National RF for this modification if desired.
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Mini Receiver
FB7-NX
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.
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MOD MONITOR
TYPE HFX-1
The Type HFX-1 Modulation Monitor is an ancillary piece of equipment, which is used with narrow bandwidth, or older oscilloscopes to allow viewing of RF signals and particularly modulated signals as high as 55MHz. The equipment contains an RF signal source and a broadband mixing circuit which converts the high frequency signal to an intermediate frequency within the oscilloscope’s range. The frequency control dial is simply adjusted until the RF signal is viewed on the scope. BNC connectors are mounted on the rear panel to allow interconnect to the scope and RF probe. This product was previously called "oscilloscope frequency extender" and may be used to view other high frequency signals on older or narrow band scopes.
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Attenuators
The National RF line of attenuators are compact, affordable attenuators which are ideal for insertion between a direction finding antenna and a receiver/transceiver, to aid in the DF process. In addition, they may be used in the laboratory for a low-power, in-line attenuation purposes. The affordable price is achieved by utilizing standard 5% tolerance resistors and commercial hardware. For laboratory purposes, an attenuation versus frequency curve (to 500mMHz) is provided.
