[Aloha]

Demand for certain goods and commodities are cyclical - I design dispatch consoles, we tend to get customer verticals in clusters - public safety, power/utilities, transportation and it continues in a cycle, based on replacement intervals (on a 20 year lifetime) - I know Motorola sees similar cycles too - they'll oscillate between public safety and commercial markets.

I know there are similar business cycles in aviation, power generation and industrial controls.

[xapata]

If I understand you correctly, you're suggesting that the demand for dispatch consoles follows a wave with a 20-year period, because the device must be replaced approximately every 20 years? I can believe that for an individual buyer, but for the market as a whole to follow the same period, that'd imply that every buyer made the bulk of their purchases at around the same time. That seems unlikely.