sealant or caulk for use around ladder line

[AF5FH]

I'm trying a doublet antenna fed with ladder line. It is the DX Engineering WA-135 kit. I wanted to get the ladder line into the house to see if it is working OK. So I drilled an oval hole through the wall with a long concrete drill, and pulled the ladder line through the wall. The exterior wall is brick with mortar, and the inside wall is drywall, with a small air space between. I drilled through the mortar between 2 bricks.

I would like to seal around the ladder line to keep out insects. Are there any caulks or sealants that are safe to use around ladder line?

Jim, AF5FH

[K1DNR]

I'm trying a doublet antenna fed with ladder line. It is the DX Engineering WA-135 kit. I wanted to get the ladder line into the house to see if it is working OK. So I drilled an oval hole through the wall with a long concrete drill, and pulled the ladder line through the wall. The exterior wall is brick with mortar, and the inside wall is drywall, with a small air space between. I drilled through the mortar between 2 bricks.

I would like to seal around the ladder line to keep out insects. Are there any caulks or sealants that are safe to use around ladder line?

Jim, AF5FH

I think if it is plastic insulated ladder line, you can use almost anything.

The curing agent in many caulks/sealants is corrosive to metal - so you do have to be careful what you use if you are sealing exposed metal surfaces.

[AC0FP]

Weather sealing window line in your installation shouldn't be a problem. The caulking may cause a slight impedance change, due to capacitance, where the line goes through the wall but this shouldn't be a problem. Just keep the feed line a few inches away from any metal.

73,

fp

[AF5FH]

Thanks! I have some DAP brand clear sealant from the local store that I use to seal around windows. It is watertight, and paintable after it dries for a few hours. Should keep the insects out, and it sounds like it won't bother the plastic insulated ladder line.

Jim, AF5FH

[N3JBH]

I just spray some that expanding foam in there and paint it to match the brick when it cured.

[G0GQK]

The usual method is to change the open wire feeder to coax when it enters the house. If you have metal near to the open wire there could be a problem

Mel G0GQK

[AF5FH]

The usual method is to change the open wire feeder to coax when it enters the house. If you have metal near to the open wire there could be a problem

Mel G0GQK

Yes, I have read that also, in the paper that came with the DX Engineering antenna kit. For now, I am simply connecting the 300 ohm ladder line directly to the balanced inputs on the back of my MFJ Versa Tuner II. My tuner meter shows that forward power equals what my Icom-718 says it is sending, and the reflected power is near zero. I have found tuner settings that give me near 1:1 SWR on all bands 80 through 10 meters. My antenna is rather a compromise, 80 feet across the top at only 28 feet above ground, with near vertical tails that are 21.5 feet each. The tails end up about 8 feet above ground. I thought I should have a total wire length of 133 feet, but could not make that fit between the tallest trees on my property. I ended up with about 123 feet of bent dipole antenna and about 80 feet of ladder line feed zig zag around obstacles to the tuner. I may try something different later, but for now this seems to be working.

Jim, AF5FH