Corrosion pics from coastal Alaskan arctic sites

[arcticracer]

We battle constantly to win the war with corrosion in coastal areas of Alaska, especially in the Arctic. Here are a few pics of LNA's that have failed, one got wiped out during the recent solar outage period. The site went down during the outage and never came back, turned out the gain of the LNA dropped by about 20db, it was not the visible corrosion that took it out.

The long tube looking thing you see bolted to the LNA's is a transmit rejection filter, it's job is to keep the 6 GHZ uplink signal out of the LNA as both are bolted to the feedhorn.

 

[ayelvington]

Our radar systems had pressure windows so we could pump in dry nitrogen. Would that work for you? It helped us keep condensation out of the waveguide since it passed through serious temperature ranges and would draw in moisture for the warm interior spaces. I'm retired Coast Guard, so I understand maritime corrosion.

 

[ayelvington]

Looking more closely at the photos, I'm thinking that you might protect the non-waveguide portion of the fitting with a nice layer of conductive grease. The grease or Never-Seize would exclude the moisture from being wicked into the joint by capillary action. Just thinking out loud...

 

[arcticracer]

Ours are pressurized with .5 PSI air run through a dehydrator, it doesn't protect the outisde unfortunately.

 

[arcticracer]

The smaller of the LNA's was only 4 years old, the high winds and salt seem to get to things no matter what you try to keep it out. It's the one that died from the solar outage. The other one had the N connector break, probably from the wind beating on the heliax feedline.

 

[FaT Air]

Salt doesn't play friendly with aluminum whenever they got together. One of the biggest problems I had with RCA 2ways in the oil fields of western ND back in the 80's.