The Miniature Transmitter

These miniature transmitters go almost anywhere. They are ideal for locating in small cast iron and non-metallic lines and P-traps.

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  • Size: 5/8″ x 1 ¼” (with Drophead)
    Requires Drophead as battery cap
  • Range/cast iron:  5 ft
  • Range/non-metallic: 7.5 ft
  • Battery: #357 Button cell
  • Tone: C
  • Line Size:  down to 3/4″ (1½” P-trap)

  • Size:  3/4″ x 2-5/8″
    Can use Dropcap for Push Rod use
  • Range/cast iron:  10 ft
  • Range/non-metallic:  15 ft
  • Battery:  “N” cell
  • Tone:  C
  • Line Size:  down to 1″ (2″ P-trap)

Prices apply to US orders only

  • 16 Hz – This equipment operates at 16 Hz, a very low frequency with the advantage that it will penetrate steel or ductile iron lines (as well as cast iron and nonmetallic). It is compatible with any gear that operates at 16 Hz.
  • 512 Hz – This equipment operates at 512 Hz, the industry standard frequency for locating in cast iron or nonmetallic lines. It is compatible with any other manufacturer’s 512 Hz equipment.
  • 8 KHz – This Transmitter or Receiver operates at 8 KHz, a high frequency that works in nonmetallic lines only, but is very efficient and offers good range. Works with any 8 KHz equipment.
  • 223 KHz – This Transmitter or Receiver operates at 223 KHz, which is suitable for nonmetallic environments only. Only Prototek makes equipment that operates at this frequency (AR-1 and ATP-12).

You must match the transmitter’s frequency to the receiver’s frequency. A 512 Hz Transmitter will not work with a 223 KHz Receiver, etc.

The Range of a transmitter is the maximum distance, in feet, your receiver can be from the transmitter and still pick up a usable signal (using fresh batteries in both transmitter and receiver). The numeric part of the Part No. of every Prototek transmitter tells you what its maximum effective range is.

    • For 16 Hz transmitters, the Part No. tells you its range in steel or ductile iron lines. This range is very dependent on the wall thickness of the pipe, so the range given is pessimistic, i.e., for the thickest typical lines. Range in nonmetallic lines can be up to 3 times that in steel; the range in cast iron is slightly less than in nonmetallic.
    • For 512 Hz transmitters, the Part No. tells you its range in cast iron. You can easily determine its range in nonmetallic lines by multiplying this number by 1.5. That means the range of an FV-10, for example, is 10 feet in cast iron and 15 feet in nonmetallic.
    • For 8 KHz transmitters, the range is for nonmetallic lines only – its signal will not pass through any kind of metal. For example, the range of an HV-40 transmitter is 40 feet.
    • For a 223 KHz transmitter (ATP-12), the range is also for nonmetallic lines only.  The range of an ATP-12 flushable transmitter is 12 feet.
        Note: These Range distances apply to Prototek receivers only! We cannot guarantee your results with other receivers.

“Tone” refers to the type of signal emitted by a transmitter. All of our transmitters are one of these types; many are available either way. Which tone should you choose? Here are some considerations about each type:

C – Continuous or “Solid” Tone

• available on almost all Prototek transmitters
• best to use for determining precise depth
• compatible with most other manufacturers’ equipment

• harder to distinguish signal from interference
• shorter battery life

B – Beeping (on/off) Tone

• easier to distinguish signal from interference
• longer battery life

• difficult to use for determining depth
• won’t work with LF2000 or LF2200, or many other manufacturers’ digital equipment

357-button-cell#357 Button Cell
for current FM-05 Transmitter, or older FM-10
1.55 Volt  Silver Oxide watch/calculator battery
0.46″ dia., 0.21″ ht., 165 mAh

Note: equivalent size “Zinc-Air” batteries will not work


“N” Cell (also known as E90)
for FD-10 Transmitter, or later FM-10
1.5 Volt Alkaline battery
0.48″ dia., 1.2″ length, 800 mAh


Note: An A23 battery looks very similar, but will not work and will ruin your transmitter

393-battery#393 Button Cell
for older FM-05 Transmitter
1.55 Volt Silver Oxide watch/calculator battery
0.31″ dia., 0.21″ ht., 70 mAh

Note: equivalent size “Zinc-Air” batteries will not work