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
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Product
Resonance Dip Meter
NRM-2
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National RF’s Resonance Dip Meter is a test instrument used to determine the resonant frequency of a tuned circuit or resonant network, such as an antenna system. In addition, the unit may function as an RF detector, or a secondary frequency source. The instrument is analogous to the older vacuum tube “grid dip meter,” once popular in every electronic laboratory or radio station. Unique to this updated version is a buffered output that may drive a digital frequency counter for exact measurement of resonant frequency, or connected to an oscilloscope to be used as an RF detector and waveform/modulation monitor.
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Product
Analog Power Supply
Type NPS-2412
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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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Product
FREQUENCY DISPLAY UNIT
TYPE NFD-1
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The National RF Type NFD-1 Frequency Display Unit was designed for use with vintage and classic communications equipment, to display the received or transmitted radio frequency. The unit incorporates an internal processor that allows the intermediate frequency (IF) to be counted out by the frequency counter. The resultant display is the actual frequency that the equipment is receiving or operating at.
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Product
POWER ATTENUATORS
TYPE ATF
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National RF’s Type ATF Power Attenuators were designed to allow interfacing of linear power amplifiers to RF exciters, where a specific amount of drive to the amplifier is prescribed. Often, however, drive from the RF exciter exceeds this minimum prescribed level and some form of power attenuation must be used in order to not damage the input of the power amplifier. National RF’s type ATF-3 offers 3 dB of power attenuation (1/2 of the power) when used between the exciter and the amplifier and will handle an input power of 132 Watts, RMS (continuous power) while providing about 66 Watts RMS output power, when it is terminated into 50 ohms. In practice, the ATF-3 attenuator will handle exciters achieving Peak Envelope Power levels (PEP) in the area of 200 to 250 Watts while providing half of that power to the load. For less attenuation requirements, the ATF-1 and ATF-2 offer 1 and 2 dB of attenuation, respectively.
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Product
RF Milliwatt Meters
Type NDB-2 and NDB-3
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National RF’s Type NDB-2 and NDB-3 RF Milliwatt Meters are affordable pieces of test equipment for both the RF laboratory and the home experimenter. Both provide a digital reading of RF power in dB reference 1 milliwatt of power into a 50 ohm load (i.e. 0 dBm). The circuitry consists of a low noise logarithmic amplifier that drives a digital A/D converting meter circuit. The lowest power levels that can be read are about –73 dBm (approximately 40 microvolts or .00000003 milliwatts). The maximum power input should not exceed 10 milliwatts (+10 dBm or .010 watts) when inputed without attenuation. An internal attenuator is provided and described in the next section.
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Product
Precision Dials
HROII-PD and HROII-PDA
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National RF’s HROII-PD and PDA precision dials were inspired by the earlier National Radio Company’s famous HRO series of communications receivers. This earlier equipment incorporated a ten turn dial with a rotating number plate on the inside. Every 72 degrees of rotation, a new number appears in a rectangular cutout in the dial skirt. The numbers count from 0 to 500 in decade intervals. The HROII-PD and PDA duplicate this counting action but in a smaller diameter assembly than the earlier dial.
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Product
Reference Antennas
Type NRD
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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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Product
TURBO-TENNA 137 MHz Weather Satellite Antennas
WX-137 SERIES
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The WX-137 series of antennas are marine-grade 137 MHz circularly polarized antennas designed to receive weather satellite images from the polar orbiting NOAA and Meteor satellites. Manufactured from stainless steel and ABS plastics, the assemblies are sealed and designed to survive marine service, although they may be used on land as well. Each antenna is available with or without a gasfet preamplifier which provides about 16 dB of gain and is physically located adjacent to the antenna.
