[NLRS] New Iowa noise source proposed.

[Dr. Gerald N. Johnson]

There is a company proposing to build a +/- 600 Kv (two wire, not 
depending on a ground return like the one from Washington to Los Angeles 
out west) from NW Iowa to northern Illinois to provide a path for power 
from a couple thousand more wind mills. It won't have taps, just is 
planned to run power from NW Iowa to Illinois. Each converter station is 
expected to cost about a quarter billion bucks. I'm concerned that RF 
noise through microwave frequencies may turn its path into a noisy place 
unsuited for radio communications. AC lines are a bother but the noise 
happens only at the voltage peaks, 360 times a second for 3 phase lines, 
sometimes 720 times a second near a delta-Y connected transformer that 
introduces a 30 degree phase shift on the voltage waveforms. And noise 
blankers working on the noise peaks can be effective at shutting off the 
receiver during each noise burst. The trouble with a DC line is that 
there are not peaks, the RF noise is continuous and so the noise blanker 
is not effective at allowing reception. And at VHF and up, there's no 
significant propagation along the line so there's no correlation between 
the corona spikes from one pole to the next which makes cancellation by 
using two antennas not work. At an open house last week the engineer 
admitted AM radios along the line were bothered, he hasn't learned about 
ham and VHF communications, but if I can keep up on the project, I just 
might educate him at some Iowa Utilities Board hearing in the future.

73, Jerry, K0CQ