Similarly the receivers are designed to be tuned to receive only this transmitted frequency and not extraneous noise from AC emissions, computer screens etc. ; the complex receiver circuitry of a top-of-the-line receiver includes considerable noise-rejection circuitry as well as signal-discrimination circuitry. One way to identify the better transmitter-units is to ask how deep the transmitter signal can be detected in a typical 4-inch lateral cast-iron pipe. If the system has a capability of fifteen feet, you are assured of being able to locate on virtually 100% of your jobs.

If less than this, you may be able to do only ,say, 16 of 20 locates and have to explain to the customer , for the other 4 jobs, that you will just have to do the old trial and error "pothole" method until you locate the problem. Receivers from different manufacturers have different controls and data outputs. Receivers used by municipalities on a continual basis , usually by the same person, often have extra features that need to be accessed by sequential programming similar to setting up VCRs.

For those in the plumbing trade, where the receivers are used on a more infrequent basis and by a larger number of persons it is best to keep the controls as simple as possible so it is not necessary to look at the instruction manual each time. The MicroEngineering PS-200 system receiver, has a separate control for each feature and a separate panel light to show when that feature is in use.