Topband: Lubrication for an RF whip

[Dave Anderson, K4SV]

Hi Guys,

I have designed a vertical antenna made from 6 sections of Rohn 25. It sits on insulators and has an extendable while 45 foot long made from telescoping AL tubing. The whip can be adjusted remotely using the converted Ryobi drill motor winch I fabricated. The antenna will be used on 80 and 160 with appropriate impedance matching. It’s kind of like a screwdriver antenna without the coil.

I want to know if anyone has had experience on using lubrication on antennas that move. The whip has a set of contacts at the top of the tower and no matter what length the whip is extended it will make contact as it slides up and down. The whip is T6061 AL and the contacts are copper. What would lubricate these contacts, not attract dirt and not create noise?

Thanks in advance,


Dave, K4SV
Asheville, NC




----- Original Message ----- 
From: Dave Anderson, K4SV 
To: topband at contesting.com 
Sent: Tuesday, September 02, 2003 10:25 PM
Subject: Topband: Rohn Tower for 160/80 antenna


Hi All,

Wanted to ask if the normal calculation for a 1/4 vertical applies (234/F(mhz) = Feet of antenna for 160 meters using a Rohn 25G section of tower for the radiator (125 foot)?

Second part.
If I made the bottom a 60 feet Rohn 25G tower section with 50 foot of tapered AL tubing and a small inductor to resonate all sitting on insulators, would there be a better calculation for length? Has anyone tried this? What is better?  Yeah I know, a 2 element beam for 160, but it wont fit the backyard.

Thanks in advance,

Dave, K4SV
Asheville, NC


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