on 8/12/03 7:20 PM, Mark Petry at mpetry@bainbridgeisland.net wrote:
> This type of pump was supplied by Andrew Antenna Co. It was used to
> pump dry air into the waveguides of microwave antennas as used by the
> telephone company, satellite communications stations, etc.
>
> Cool dry air in the waveguide ensures the best possible signal
> propagation characteristics especially in the higher frequencies (X, K
> band, etc) where the microwave signal is partially attenuated by
> airborne water vapor.
>
> They don't use these anymore - in modern microwave systems the waveguide
> is purged with nitrogen from a tank. I'd really like to have a pump
> like this !
Good call! In a previous life, I was a microwave product manager for Motorola and Telesciences. We used the nitrogen but short runs of waveguide could use a small cannister of dessicant.
So, Mark, you aren't an RF engineer, are you?
(BTW, LaSalle is about 90 minutes from Motorola world headquarters in Schaumburg, IL and from Andrew headquarters in Orland Park, IL).
Todd Kuzma
Heron Bicycles
Tullio's Big Dog Cyclery
LaSalle, IL 815-223-1776
http://www.heronbicycles.com
http://www.tullios.com