Range to Fault (RTF)

PIM & Return Loss Measurement

Range To Fault (RTF) is an exciting technology from Kaelus that enables operators to accurately measure the location of PIM and Return Loss faults in their RF infrastructure. Reflection data together with PIM data provides an unmatched level of clarity for identifying the location of faults in the RF path. The RTF system consists of an RTF Module, interconnecting cables and an “RTF Enabled” iPA or iBA series PIM test instrument. Customers can purchase a new “RTF Enabled” PIM test analyzer from Kaelus. Please contact your local Kaelus representative for additional information.


  • Accurately identify the location of PIM and Return Loss faults in the RF path
  • Simple to operate, highly intuitive touch screen user interface
  • Overlay PIM and Return Loss vs. distance data for enhanced troubleshooting capability
  • Quickly switch between different test modes without disconnecting the line under test
  • Compatible with any “RTF Enabled” series PIM test instrument from Kaelus
  • Speeds site repairs by guiding operators to the location of PIM faults
  • Before PIM testing, the RTF Module performs a Return Loss safety check to warn the operator before transmitting high RF power into a poor match

technical specifications
key specifications
RTF analysis modes Numeric: Distance to maximum PIM + PIM Magnitude
Graphical: PIM vs. Distance, Return Loss vs. Distance, PIM + RL vs. Distance
Return loss Max Return Loss (from FFT analysis) is displayed on the main PIM test screen when the RTF module is attached
Residual PIM < -120dBm/-163dBc maximum (<-125dBm/-168dBc typical) @ 2 x +43dBm test tones
User interface ports 1x USB, 1x Auxiliary port (Type N female)
1x RF output (7-16 DIN female), 1x RF input (7-16 DIN male)
Power +12V DC supplied via auxiliary port
RF power (PIM) 2x +43dBm supplied by iPA or iBA
RF power (Return Loss) -20dBm supplied by RTF module
Dimensions H x D x W 127 x 90 x 73mm | 5.0 x 3.5 x 2.9in
Weight 1.0kg | 2.2lbs
Temperature range -10ºC to +40ºC | +14°F to +104°F
Ingress protection IP50 (operating)
Operational humidity 5% to 95% RH non-condensing
Storage temperature range -20°C to +60°C | -4°F to +140°F
ordering information
rtf module
USB cable, Auxiliary port cable and carrying case included with RTF Module.
RTF-1000B RTF Module, 600 - 960MHz 0600, 0700L, 0700H, 0703, 0790, 0850, 0900, 0901 0600, 0707, 0703, 0790, 0850, 0900, 0901
RTF-2000B RTF Module, 1710 - 2170MHz 1800, 1900, 1921, 2101 1800, 1921, 2101
RTF-2600B RTF Module, 2300 - 2700MHz 2600 2600
peak return loss
When the RTF module is attached to the PIM test analyzer a low power Return Loss vs. distance measurement will be made prior to activating the high power PIM test tones. If the peak calculated Return Loss is greater than a user specified value, a warning will be presented to the operator along with the distance to the failing location. The operator has the option at this point to either abort the test or continue with the PIM measurement. This safety feature has been added to help prevent accidental high power RF transmissions while the feed system is open for repairs.
distance to largest pim source
With an RTF Module attached, the user software provides four different views the operator can use to analyze PIM faults at the cell site. The “Basic” view clearly identifies the distance and magnitude of the largest static PIM fault on the line. For fastest results, Kaelus recommends methodically eliminating the largest PIM fault and repeating until all static PIM sources have been removed. Once the static PIM sources are removed, the operator can proceed to dynamic PIM testing to certify that the PIM performance is stable and robust.
pim vs. distance
With a single button push, the operator can switch to “PIM” view to see the magnitudes of all PIM sources on the line. A marker function is provided allowing the user to jump from peak to peak displaying the magnitude and distance to each PIM fault. Kaelus’ RTF solution utilizes proprietary enhanced resolution algorithms that enable the user to resolve closely spaced PIM faults that a standard FFT analysis can not see.
return loss vs. distance
With a second button push, the operator can switch to “RL” view to see Return Loss vs. distance. As with the PIM view, a marker function is provided to display the magnitude and distance of each Return Loss peak.
pim & return loss overlay
“OVL” view overlays Return Loss vs. distance and PIM vs. distance on a single screen. The user can independently set markers for both PIM peaks and Return Loss peaks and measure the relative distance between faults. Electrically long devices such as filters or TMAs, and changes in velocity factor caused by jumper cables vs. feeders can reduce the absolute accuracy of individual distance calculations. Since these errors impact both the PIM and Return Loss calculations equally, the relative distance between faults is typically more accurate than the individual distance calculations. Using the relative distance of a PIM problem to a known Return Loss peak allows users to locate faults on the line with more precision than with PIM vs. distance alone.