I recently picked up an Icom M802 marine HF radio that includes ham bands and an Icom AT-140 antenna tuner. I have a ham license, but have been away from HF for many years and have never used a random wire antenna before.
Ultimately I may want this on my boat for WX data, GRIBs, email and so on, but before doing that I want to get it running at home and experiment with some data over HF. I need an antenna and don't want to spend much on a pricy indoor loop or the like, and I don't have an attic. I live on a small lot with an HOA and based upon the layout it's best physically to use an end fed long / random wire. I would like to operate on 80 to 10 meters, although I'm not sure I have enough space for that.
The house is on a slab and all the plumbing is plastic. The radio needs to go on the second floor. Fortunately there is a window that leads out to a roof and I can put a mounting hook into the side of the house. I can also mount the tuner there (it's designed for outdoor mounting). This would give me 20 or more feet above ground.
The tuner has a screw lug to connect the end of the long wire, but I'm concerned about connecting the wire directly to the tuner. I don't know how strong that lug is.
The tuner manual says to avoid multiples of half wavelength as the radiating element, and says if I use a 15 meter wire I can operate all marine bands from 1.6 MHZ to 25 MHz. Further, consulting this link is helpful:
This would rule out a 49 foot 2.5 inch (15m) length due to wanting to use 80 meters but allow 71 feet, although I may not have enough space. I could do 40 feet for sure. If I do 40 feet I can go between two points on the house (preferable because the house won't swing in the wind) but for 71 feet I would need to go to a tree on someone else's property (which I can do if need be).
My questions are:
Can I string the wire between two mounting points and use another, shorter wire from the tuner to the antenna wire? It could be very short, like a foot or so.
If the end of the antenna has to go directly to the tuner, I'm concerned about a strain relief so the tuner mount point is not damaged. That's why I asked the above question. Is there a better approach?
How do I do a ground or centerpoise? The tuner is supposed to be grounded, so do I put a ground rod into the dirt and run a wire down to it? Would that be a centerpoise?
Can I use the ground lug of an electrical outlet as a counterpoise?
Can I use a wire shorter than 71 feet for 80 meters effectively? The tuner manual seems to imply that I can use antennas less than 1/4 wavelength in length.
What type and gauge of wire is best to use for the antenna? Can it be insulated to prevent rust?
I know this is asking a lot, sorry, but I would greatly appreciate the help, thanks!!