Grupa: Administrator 
Lokalizacja:: Kłodzko JO80IK
Posty: 39637 #8126877
Od: 2013-10-18
| #52: Tutorial / Basics of a Dip Meter
This video presents the basics of a Solid State Dip Meter, which is the more "modern" equivalent of the old classic Grid Dip Meter (GDO). The GDO was simply a vacuum tube based oscillator with a meter that read grid current as a measure of the oscillation strength/magnitude. The solid state dip meter uses a solid state RF oscillator and detector circuit to perform the same function.
The Dip Meter (or Dipper) I show in the video is a Heathkit HD-1250 that I built as a kid in 1976 or '77.
The dipper is mainly used to determine or measure the resonant frequency of a circuit, antenna, 1/4 wave transmission line, crystal, filter, etc. You couple the dipper's exposed coil to your "device" under test, and adjust the frequency of the dipper until a drop or dip in noticed in the meter. Once the dip is found, the frequency is read off of the dial.
The theory of operation is that the signal from the oscillator is injected into the circuit/device under test. Then the frequency produced by the dipper hits the resonant frequency of the DUT, the strength of the oscillation will decrease due to the resonant load.
There are a lot of applications for this: determining the resonant frequency of a circuit, or an antenna, of a crystal or filter, etc. Also, using known capacitors or inductors, you can use the dipper to help measure the values of unknown inductors or capacitors. You can determine 1/4-wavelength transmission lines and other resonant RF structures like traps. The meter can also be used as a RF signal source for testing receivers, etc.
By turning the oscillation level in the dipper to the point where is just goes away, the dipper can then be used as an absorptive wavemeter - or a frequency selective field strength meter.
The "Dipper" is a very flexible and versatile instrument, that has been around for decades, but isn't seen that often anymore unfortunately.
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