Electrical safety inside the ham shack is covered in the National Electrical Code. Arcing at a poor electrical connection is one cause of broadband radio frequency interference at an amateur radio station.
Assuming the equipment is connected to a ground rod, if you receive an RF burn when touching your equipment while transmitting on a HF band, the problem might be that the ground wire is resonant. RF hot spots can occur in a station located above the ground floor if the equipment is grounded by a long ground wire. One good way to avoid stray RF energy in an amateur station is to keep the station's ground wire as short as possible. Connect all ground conductors to a single point to avoid a ground loop. ALL of the following are important reasons to have a good station ground:
Distorted speech is heard from a public-address system if there is interference from a nearby single-sideband phone transmitter. The effect on a public-address system if there is interference from a nearby CW transmitter is on-and-off humming or clicking. An RFI filter at the affected telephone should be installed if a properly operating amateur station is interfering with a nearby telephone. A bypass capacitor might be useful in reducing RF interference to audio-frequency devices.
Induced currents in conductors that are in poor electrical contact can cause unintended rectification of RF signal energy and can result in interference to your station as well as nearby radio and TV receivers. A reason to place ferrite beads around audio cables to reduce common mode RF interference is because they act as a series inductor.
One measurement that can be made with a dip meter is to determine the resonant frequency of a circuit. A pronounced dip on the plate current meter of a vacuum tube RF power amplifier indicates correct adjustment of the plate tuning control. The correct adjustment for the "Load" or "Coupling" control of a vacuum tube RF power amplifier is maximum power output without exceeding maximum allowable plate current.
High input impedance is desirable for a voltmeter because it decreases the loading on circuits being measured. An advantage of a digital voltmeter as compared to an analog voltmeter is significantly better precision for most uses.
A signal tracer would normally be used to identify an inoperative stage in a receiver.
An oscilloscope is an instruments used to measure the output of a singlesideband transmitter when performing a two-tone test of amplitude linearity. A two-tone test analyzes a transmitter's linearity. Two non-harmonically related audio signals are used to conduct a two-tone test. An oscilloscope contains horizontal and vertical channel amplifiers. An advantage of an oscilloscope versus a digital voltmeter is that complex waveforms can be measured. The attenuated RF output of the transmitter is connected to the vertical input of a monitoring oscilloscope when checking the quality of a transmitted signal. The best instrument to use to check the keying waveform of a CW transmitter is a monitoring oscilloscope.
Negative feedback is used to neutralize an RF amplifier. A neutralizing circuit cancels the effects of positive feedback in an RF amplifier. The reason for neutralizing the final amplifier stage of a transmitter is to eliminate self oscillations.
A field-strength meter may be used to monitor relative RF output when making antenna and transmitter adjustments. The radiation pattern of an antenna can be determined with a field strength meter. Close-in radio direction-finding might be a use for a field strength meter.
A noise bridge is normally used by being connected between a receiver and an antenna of unknown impedance and adjusted for minimum noise. Pre-tuning an antenna tuner is one way a noise bridge might be used.
Standing Wave Ratio can be measured with a directional wattmeter. Antenna and feedline must be connected to an antenna analyzer when it is being used for SWR measurements.
One use for a DSP in an amateur station is to remove noise from received signals. DSP filtering is accomplished by converting the signal from analog to digital and using digital processing. An advantage of a receiver IF filter created with a DSP as compared to an analog filter is that a wide range of filter bandwidths and shapes can be created. A DSP filter performs automatic notching of interfering carriers. ALL of the following are needed for a DSP IF filter -- Analog to Digital Converter (A to D), Digital Processor Chip and Digital to Analog Converter (D to A).
One reason for using a properly adjusted speech processor with a single sideband phone transmitter is that it improves signal intelligibility at the receiver. A speech processor affects a transmitted single sideband signal by increasing the average power. ALL of the following can be the result of an incorrectly adjusted speech processor -- Distorted speech, Splatter and Excessive background pickup.
An S-meter measures received signal strength. An S-meter is generally found in a receiver. The power output of a transmitter must be raised approximately 4 times to change the "S" meter reading on a distant receiver from S8 to S9. Assuming a properly calibrated S meter, an S-meter reading of 20 db over S-9 compared to an S-9 signal indicates it is 100 times stronger.
A Type-N connector is a moisture resistant RF connector useful to 10 GHz. A DB-9 connector would be a good choice for a serial data port. UHF connectors are commonly used for RF service at frequencies up to 150 MHz. RCA Phono connectors are commonly used for audio signals in amateur radio stations. The main reason to use keyed connectors over non-keyed types is to reduced chance of damage due to incorrect mating.
The HF mobile antenna system limits the effectiveness of an HF mobile transceiver operating in the 75 meter band. ALL of the following emission types are permissible while operating HF mobile -- CW, SSB and FM.
Alternator whine is a tone or buzz in transmitted or received audio that varies with engine speed.
A direct, fused connection to the battery using heavy gauge wire would be the best for a 100-watt HF mobile installation. It is best NOT to draw the DC power for a 100-watt HF transceiver from an automobile's cigarette lighter socket because he socket's wiring may be inadequate for the current being drawn by the transceiver.
An emergency generator should be located in a well ventilated area. When being charged a lead-acid storage battery may give off explosive hydrogen gas. A primary reason for not placing a gasoline-fueled generator inside an occupied area is the danger of carbon monoxide poisoning. It would be unwise to power your station by back feeding the output of a gasoline generator into your house wiring by connecting the generator through an AC wall outlet because it might present a hazard for electric company workers.
The name of the process by which sunlight is changed directly into electricity is Photovoltaic conversion. The approximate open-circuit voltage from a modern, well illuminated photovoltaic cell is 0.5 VDC. Doped Silicon is used as the active element of a solar cell.
A disadvantage to using wind power as the primary source of power for an emergency station is that a large energy storage system is needed to supply power when the wind is not blowing.