17: How to choose between a Source & Meter, LTS, or Two-Way Instrument

Source & Meter

Advantages compared to LTS:

More flexibility. One source & meter can measure a link, whereas two LTS (Loss Test Set) instruments are needed.
A source is not needed to do transmission power measurements, so it can be used elsewhere.
The KI7600 series power meter has a built in visible fault locator option.
A single source instrument can have both multimode and singlemode emitters.
The source and meter should be matched so that “Autotest” works.

Disadvantages compared to LTS:

Higher initial cost. One LTS may be cheaper than a source / meter pair.
More inventory to maintain and deploy, so higher ongoing costs.
Higher battery cost.
Slightly harder to use.

Loss Test Set

Advantages compared to source and meter:

Maybe lower initial cost.
Less inventory to maintain and deploy, so lower ongoing costs.
Lower battery cost.
Slightly simpler to use.

Disadvantages compared to source and meter:

Generally can’t verify a link with just one unit, at least two are required.
Source (cost) must be carried during power measurements, when it’s not required.

Two Way Instrument

Advantages compared to LTS:

Much easier & faster two way (bi-directional) loss checking with minimum skill level.
Pass / Fail display.
Option of ORL measurement for small extra cost and no extra effort.

Disadvantages compared to LTS:

Initial Cost.

When considering these options, remember that the Total Cost Of Ownership is usually dominated by labour, calibration, training, inventory management and other indirect costs.