The Most Common Frequencies

The Most Common Frequencies

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About The Most Common Frequencies

RF = Radio Frequency - above 10 kHz

AF = Audio Frequency - at or below 10 kHz

HF = High Frequency - usually in the 82 kHz range of RF (some use much higher)

LF = Low Frequency - usually in the 571 to 512 range AF

('HF" & "LF" used for locating frequencies in this locating discussion only, not to be confused with Broadcast Bands.)

Some locators use the 8 to 10 kHz frequencies of AF. They claim to be LF but actually are in the Mid-range and have some of the advantages and disadvantages of both HF and LF. In the MAC-51B x we chose to give you the option to pick HF, LF, or both, plus magnetics so that you could have the full advantages of them all.

RF or HF Properties

RF power restrictions hold down Transmitter power - keeps distance down.
HF has a fast signal wave which uses energy fast. Both above are indicators that HF is good for short distances.
HF signal is excellent for jumping gaskets & gaps - looses energy doing so.
HF can be used in both the Inductive & Conductive Modes.
HF in the Inductive Mode is most convenient, as the utility does not have to be exposed to clip onto.
HF can be induced into a line via an Inductive Signal Clamp which clamps around an exposed target line to apply the HF signal to a particular line. Can penetrate insulation to avoid clipping on.

LF Properties

A slow signal wave which does not dissipate energy as fast as HF, and will not re-radiate a signal as HF does.
LF Transmitter can use a higher power to drive signals farther. Both above are indicators the LF is good for long distances.
LF signal does not jump gaskets & gaps - can be used to estimate the location of a break in a line.
LF can only be used in the Conductive Mode since it does not radiate.
LF use requires the Transmitter to be clipped onto (conductive) the target line - so the target line must be exposed & uninsulated … Caution must be used not to clip onto live power lines.
LF cannot use an Inductive Signal Clamp because it cannot be induced; it does not jump the gap between the clamp & the target line.
LF will stay on the line you put it on & not bleed on to other lines.