Ask most trained operators how they start a survey and you get the same answer: Power mode first, then Radio, then the Genny if nothing has shown up. It is the order they were taught, and it is often the order written into competency documents and assessment checklists. This piece walks through why that sequence is the wrong way round — and what the industry's own documentation says about it.
The sequence everyone is taught
Across the industry, companies say they want Genny usage up and strikes down. There is a contradiction sitting inside that: if increased Genny usage is the goal, and if it is widely accepted that many strikes could have been avoided with a transmitter, why is the transmitter left until last?
What the manufacturer manuals say
The evidence for the Genny being the most effective tool does not come from Sygma. It comes from the manufacturers. User guides state that power and radio signals may not be present, and advise using a Genny whenever searching for pipes. Instruction manuals describe the Genny as the most reliable way to detect a pipe or cable. The Radiodetection ABC book makes the point plainly: despite passive signals existing, the best signal to trace is an active signal that has been deliberately applied.
A Leica blog post suggests up to 60% of buried utilities could be missed when detecting in passive modes only. In practice, based on Sygma's own training data, the figure may be closer to 70 or 80%. The C-Scope manual puts it this way: most buried metallic services not found in Radio mode should be detected using a generator. These are not fringe opinions — they are in the documentation that comes with the kit.
The logic problem with passive first
The most common defence of the Power, Radio, Genny sequence is: we use passive modes first, and if we do not find anything, then we use the Genny. That statement contains its own contradiction — it admits the Genny will find what the passive modes missed. So why not use it first?
The same logic applies to an initial sweep. If it finds nothing, you still need the Genny. If it finds something, you still need the Genny to trace it properly. Both outcomes lead to the same place — so what is the initial sweep actually achieving?
What about avoidance mode?
Newer locators include an avoidance or all-scan mode that appears to scan Genny, Power and Radio simultaneously, and some workflows recommend an initial sweep in it. The CAT4's own technical specification shows the sensitivity in avoidance mode is the same as in the individual modes — it will not detect anything they could not. And because detailed individual scans are still required regardless, starting with the Genny and finishing with Power and Radio is more efficient, and harder to shortcut under time pressure.
Time pressure, and the Genny that never gets used
On a real site, under real time pressure, the step that goes last is the step that gets skipped. If the Genny is the last thing on the list, it is the most vulnerable to being dropped when the job feels routine. Sygma's training data consistently shows a significant increase in Genny usage among operatives trained Genny-first. The method is not technically difficult — the training is about making it the first instinct rather than a fallback.
Looking at the data differently
Many companies measure Genny usage through pie charts from CAT data downloads, looking for roughly equal use across modes. But if 60% or more of buried utilities can only be found with the Genny, equal usage is not the right target. More importantly, pie charts do not show which mode was used first. Drilling into the raw data to see how surveys actually start tells you whether operators are working the way they were trained — or reverting to passive-first once they are back on site.
Rewritten for the Bureau from the original. Method drawn from Sygma’s own training material.