Transmission Line Dehydrator

Maybe a strange place to begin the W6DSR's station, but here is my pressurized transmission line dehydrator. From the shack to the Log Periodic Antenna's base is buried 1-5/8 inch heliax transmission line with an air dialectric. The path to the antenna is 1-5/8" EIA hard line, all pressurized with dry air to keep the moisture out. This dehydrator and pump keeps the entire 380 foot line under extremely dry air at 5 PSI.

The ADH NETCOM dehydrator has two internal power supplies in a redundant configuration. The input is DC with a range of 16 VDC through 60 VDC or so, and they output 24 VDC regulated to run the dehydrator's heaters and pump. These switching supplies had absolutely no RFI supression, so the RF interference was unacceptable. I disconnected these internal power supplies and connected the external LINEAR supply you can see to the right of the dehydrator which generates NO RF crap.

Transmission Line's Pressure Guage

I purchased 5 of these precision absolute pressure gauges from the government for a song since I was the only bidder, and now, finally, I have a use for one. Even though it measures absolute pressure rather than the preferred guage pressure, it still is useful for a quick glance to see the current pressure.

Another downside to this meter is the units. It measures Inches of Mercury absolute, so I have a bias of about 29.95 inches Hg due to the weight of the atmosphere to which the added 5 PSI which is equivalent to about 1/2 the number of inches of Hg is easily added in my head to see the present pressure.

Operating Position

This is my "operating position" still very much experimental and under development. The upper monitor is a Samsung TV I pulled out of a neighbors recycle, and fixed by recapping the switching power supply's electrolytics. It's a 46 inch LCD which has the application HDSDR in control of my SDR receiver.

The lower monitor is the main Windows display with a web page of my own design, hosted by a Rabbit Single Board Computer (SBC) which is located in the linear amplifier rack. Presently the web page is unfinished, and only turns the SDR receiver on and off, selects a band to tune to, and turns the shack's PC on and off remotely.