06-11-2013, 10:21 PM
Some of those low loss plastics used in RF can migrate at normal temperature.
I was told a story about a war ship where the radar scanner was mounted on the funnel and there was no signal. They had replaced wiring and the antenna and nothing.
It took them a very long time to find out that a PTFE block mounting had migrated enough for the antenna to end up partly in the funnel so that the signal could not get out.
It did not get spotted until a proper engineer got sent up the funnel with all his gear.
I was told a story about a war ship where the radar scanner was mounted on the funnel and there was no signal. They had replaced wiring and the antenna and nothing.
It took them a very long time to find out that a PTFE block mounting had migrated enough for the antenna to end up partly in the funnel so that the signal could not get out.
It did not get spotted until a proper engineer got sent up the funnel with all his gear.
