While comprehensive information about North Korea’s most recent spate of GPS jamming has yet to be made available, additional and intriguing bits continue to appear every couple of days.

North Korea began jamming on the 31st of March and the last incident so far was on the 5th of April.

On Monday South Korea revealed that, unlike previous years’ episodes that originated from one or two locations, this year disruptive signals have been coming from five different sites in the north.

Media have also reported that the strength of the jamming signal has varied considerably.

This has caused some to speculate that, in addition to showing its displeasure over US exercises and sanctions, North Korea maybe testing equipment newly acquired from Russia or China. In 2011 North Korea jammed GPS in the south on and off for a period of 11 days. Some analysts reported that this was just after they acquired new military-grade jamming equipment from Russia.

Sources in South Korea report that, overall, this year’s jamming signals have tended to be at a lower power than would be expected, and certainly far short of what is possible. This, combined with the south’s mountainous terrain and the duration of the individual jamming incidents (often only 5 or 10 minutes), maybe mitigating the impact on many GPS users. Even so, thousands of navigation systems on ships, aircraft and vehicles have been impacted, as have thousands of cellphone towers.

It could be that North Korea is doing just enough to test its new equipment and irritate its neighbors, while being careful to not be too troublesome or show its real capability.