Just recently I changed from a house-mount mast consisting of 3 telescoping galvanized steel tubes to using a $35 radio shack rooftop tripod with one 3/4″ 10′ heavy galvanized pipe for mounting the antennas on. This gives me much greater stability and about 10 feet of extra height over the old method. I can fairly easily just pop out the mast from the tripod to bring my 2m slim jim antenna and my 10/11m 1/4 wave down onto the roof for repairs.

After completing the move I discovered water in my 2 meter coax line. Fortunately it all dripped away from my radio rather than into my radio. To remedy that I got a lot of electrical tape and wrapped the connector on the slim jim which was formerly just covered with a layer of silicone, evidently it didn’t seal up very well.

To get the water out of the coax I am using a shop vac. Since the point at which my feedline enters the house is the lowest point of the line, all of the water will hopefully run out. I am running the vac every 1/2 hour or so to let any excess water wick down to the dry area at the bottom, and I’ll keep doing so until it vacuums dry. In the end this cable will have to be replaced, but if I can get it dry enough to operate it will get me by for a few weeks.

The SWR of the HF antenna jumped from 1.7:1 to 3 when I moved it. I suspect that the base of the Antron A-99 is electrically connected to the external braid of the coax and that previously it was using the metal mast as the lower resonating half of a dipole. The lower pole section however should have been well longer than the radiator so it would seem unlikely that this had any major resonance unless it added up to a particular fraction of 10 meters. I haven’t come up with any more satisfying explanation however and even after adding a few turns of coil as a sort of balun the SWR is no lower than 2.3:1. I think I may just measure the pole it used to be mounted on later today to determine if it was a likely resonator or not. In any case I have bought a somewhat cheap ZMF-949E antenna tuner to deal with this issue and an upcoming antenna project.

I grounded the tripod using some old 75 ohm coax that I didn’t have any other use for, but after talking to KB0MGQ I found out that that may be a bad idea since the 75 ohm coax will resist the AC components of a lightning strike due to the inductance even with the center connected to the braid, and it may possibly resist it more than the 50 ohm cable running to my radios. Well my radios are currently on an ungrounded circuit so there’s no quick way to ground via that path, but I realize what a bad situation that is and I have ordered 50″ of ground strap which I will soon use to properly ground both the antenna mast and my radios.

For hams who don’t want to actually weld ground straps as is often recommended, I came up with another idea of using hose clamps to attach them. The clamps can be had at your local hardware store for around $1 and will let you tightly bind the ground strap to both sides. I also use hose clamps to mount smaller antennas.

After swinging around the tripod a few times to see how much force it could handle I determined that I don’t yet need to run any guy wires to support the structure. I plan to add a good sized yagi or cubical quad to the mast in the future however so that may change. I positioned the tripod where I should have 3 solid points from which to anchor it when the time comes.