23. Switching Power Supplies In a switched mode power supply, the first step in converting 120 V ac to a 12 V dc output is to rectify and filter the 120 V.
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29. Test Equipment: V-O-M (Analog Multi-Meter) A Volt-Ohm Meter, incorporating an analog meter which the user must ‘read’ in order to obtain useful information fro the meter. Measurement ‘range’ and metering ‘mode’ selection is provided by a rotary switch. Accuracy is often +/-10% of the meter reading, not including the user’s ability to ‘read’ the meter itself. A handy tool for the Amateur.
30. Test Equipment: DMM (Digital Multi-Meter) In use, not significantly different from the analog V-O-M, other than the fact that the readout is numeric and tends to possibly ‘imply’ a higher accuracy than the meter may be able to provide. Users tend to ‘trust’ the implied high-accuracy of a digital readout more than they trust an analog meter when they have to read and interpret the needle position. Also a handy tool in the shack.
31. The difference between the accuracy of a V-O-M (+/- 5% to 10%), when compared to that of a DMM (usually +/-0.1% to 1%) may or may not be of much importance to the user. When using a meter, many times the importance of the reading is not the absolute accuracy, but the difference between toe readings taken with the same meter . It may be much more important to know whether reading #2 was higher (or lower) than reading #1, than to know whether the reading is within 1% of the intended value. So, while a DMM may give more accurate readings, the V-O-M may provide just as usable measurements under certain circumstances. V-O-M vs. DMM Accuracy
32. Test Equipment: SWR and Watt Meter These devices allow you to keep track of the degree of ‘match’ between your transmitter (50 Ohm) output and that of the antenna/feedline ‘load’ being provided to the transmitter. They also allow you to monitor your transmitter output power.
33. Test Equipment: Antenna SWR Analyzer This device incorporates the features of a very low-power transmitter and an SWR meter into a single, portable, device which can be used to obtain important information about the antenna to which it is attached. It allows you to ‘tune’ the antenna without transmitting signals harmful to communications on the same frequency.
34. Test Equipment: Station Monitor Scope The station Monitor scope allows you to ‘see’ your transmitted signal in real-time. It is installed in the transmission line so it can actually ‘look’ directly at your signal as you transmit. So if there is a problem with the signal, you can see the indication and take steps to fix it before it becomes a problem for others. The image below, illustrates a single Morse Code DIT (dot) which has been ‘stopped’ on-screen for the operator to examine
35. Test Equipment: Station Monitor Scope Sample Monitor Scope RF Envelope Waveforms Continuous Carrier Input No RF Signal Input Morse Single DIT SSB Voice SIgnal
36. Test Equipment: Oscilloscope Oscilloscopes are specialty test devices which can be of use to the radio amateur in certain instances. They allow you to ‘ look’ at signals of all kinds and to use what you see for analytical purposes. ‘ Scopes can be costly, but can be worth the investment if you have a real use for them. They are NOT specifically ‘ required’ for the normal ham’s shack however.
37. Test Equipment: Oscilloscope Using an oscilloscope to compare the values of two different signal inputs (red and lt. blue, below).
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