One of the most important gear we must have is a SWR meter. It's a really simple thing that without his presense our shack can gonna be screwed up by. So, what is that gear?
SWR meter or VSWR (voltage standing wave ratio) meter measures the standing wave ratio in a radio transmission line. This is an item of radio equipment that used to check the quality of the match between the transmission line and antenna.
The gear should be connected in the line as close as possible to the antenna, because all practical transmission lines have a certain amount of loss, causing the reflected power to be attenuated as it travels back along the cable, and producing an artificially low VSWR reading on the meter. If the meter is installed near to the antenna, then this problem is set down.
Note that an SWR meter does not measure the actual impedance of a load (ie the resistance and reactance), but only the mismatch ratio. To measure the actual impedance, an antenna analyzer or other similar RF measuring device is required. Note also that for accurate readings, the SWR meter must be matched to the line impedance, ie 50 or 75 ohms as applicable. To accommodate both impedances, some SWR meters have switches on the rear, to select the appropriate load resistance for the sense lines.
If there is a mismatch between the transmission line and load, the line will act as an impedance transformer. At this time, the impedance seen at the input to the line will depend on its electrical length, eventhough (for a lossless line) the VSWR will be the same at any point within the line. Mismatched transmission lines are usually used for impedance transformation, especially at UHF and microwave frequencies where their dimensions can be so short.
In simple words, what swr meter are for? Swr meter are used to measure how many reflected power within the transmission line going back through the line? Bigger is worse. Lower is better. So, watch your meter every time you do a QSO? My elmer said, eventhough you're in a very-very happy big pile up, if your meter show 1.5 number, Please stop it away or your gear will blown away.... Wannya see your gear blown away, keep watching on your meter, and let it fly far-far away from 1.5 scale...
Best 73,
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