Thanks much.

Thanks all.

So is it MM or GM?

Thanks. I looked, not exactly clear and concise as the info is a bit scattered and is mostly links to other sites. I'm amateur extra so I get full privileges in CEPT countries.

Ok, I'm still a bit confused about exactly what prefix to use.

Thanks

I'm not sure if I'm in the right forum or not. Anyhow, I have the chance to go to Scotland for work so I'm going to bring my 6m/2m/1.25m/70cm APRS handheld along with me. I have read and understand the CEPT licensing and reciprocity rules. They sound pretty simple, I just need to carry my license and a few other papers. I think that my callsign becomes W4/AK4SK, is that correct? Any other info that is good to know or that I should keep in mind?

73

I got a random wire put up a week ago Saturday. I'm not sure of the length, 200'+ and the height varies from a little over 20' at the feed point to maybe 30' in some places back down to 15' or so at the far end. It's also in a "L" shape horizontally. I have a 4:1 current balun at the feed point with one side going directly to a dedicated ground. So far I'm pretty happy with it. I can tune it anywhere I want from 1.8 to 54 MHz. No issues with RF in the shack so far but I haven't tested in it on all bands at high power (100W).

I finally got a hold of my ARRL antenna book, I'm afraid that there isn't much info on random wire antennas in there, I was a bit disappointed.

I have a question about grounding related to lightning protection. It is recommended that the shield side of the coax should be grounded to the tower/mast near the feed point and then again at the base of the mast. That is a general statement I have found regarding feed lines and lightning protection. Is that true for wire antennas such as the random wire being discussed here and others such as dipoles? So in this particular installtion following that recommendation the shield side of the coax would be grounded to the mast via a grounding block immediately before the coax goes into a balun/unun that feeds the antenna. Is that correct?

I appreciated all of the replies. For the record I have a copy of the ARRL antenna book and I reference it often. In this case I had just moved so it was in a box somewhere. I always do try to do my own research before asking questions, that way my questions are as pointed and intelligent as possible and so that I can better understand any answers I receive. Anyhow, as I mentioned there is a lot of conflicting, or at the least incomplete, information on random wire antennas out there. I think that I now better understand some of it.

It sounds like an ideal instillation would be no balun or unun and a very good RF ground and/or counterpoise. I don't think my RF ground will be great and a counterpoise isn't going to happen. So in that case it sounds like a 1:1 current balun right at the antenna feed point would be a good choice. My understanding is that I should have two RF grounds: my regular station RF ground and a separate RF ground for the ground wire coming off of the balun and that these two grounds should ot be connected. Is that correct?

By the way, to get the ~200' length I'm looking for my antenna will have to be "L" shaped, one ~140' leg and one ~60' leg. Is that a big deal?

Thanks for the lengthy reply.

My shack will be on the second floor. I can pretty easily get the feed point of a wire antenna up about 30 feet or more off the ground. I have two choices. My tuner does have a coax socket so I could attach the antenna right there and run it out the shack, up the mast, and down the back yard. I could also run 15-20 feet of coax from the tuner to the top of the mast and feed the antenna from there.

For grounding, my whole entrance bulkhead will be grounded right below the shack including all of the coax shields, radio RF ground, and tuner RF ground. Is that sufficient if the coax running to the antenna has its shield grounded with the rest of the shack? There will only be about 5 feet of coax before it reaches the bulkhead and is grounded. What if I just run the wire straight from my tuner, is the RF ground from the tuner sufficient? I would have trouble running both an elevated counterpoise and/or burying 1/4 wave radials. I have a young son that would easily be able to access the counterpoise wire and radials are impossible because my station ground is a small piece of earth surrounded by concrete in every direction. My only choice is a ground rod.

What do you mean by bending the wire in the middle, like an inverted vee? My random wire might end up being L shaped to get the length I need but with the whole thing parellel to the ground and the short end of the L just turning perpendicular to the long leg.

There is so much conflicting information out there. LDG recommends their 4:1 voltage balun, DX Engineering recommends their 4:1 current balun, W8JI recommends a 1:1 current balun, Mike recommends a 9:1 or 4:1 unun and a current balun. Some people say that the shield must be grounded, others that it should absolutely not be grounded.

There doesn't seem to be any consensus at all...

Rich,
I'm mainly looking for an easy to install multiband antenna. I had a full wave loop cut for about 3.2 MHz just by random chance based on how I routed it around my property at my old QTH in Fort Walton Beach. I could work everything from 80-10 meters well enough. I'm in Freeport, FL now so I'm still setting up my station. I was going to put up another loop but I'm not sure that I want to go to that effort at my new place. I could put up a much better loop now but it would take a good bit of effort. I'm not trying for any specific awards or anything at this point although I like JT65 and WSPR a lot. I pretty much have to have a horizontally polarized antenna for regional and local MARS contacts. Eventually I want to get something like a spider beam or a hex beam for 20 meters and above. For right now I'm looking for something that is easy to put up that'll get me on the air on most of the HF bands and preferably something that will work well on 80 meters and a little below. I have a two story house so I can use that to support my antennas without having a free standing mast or tower out in the yard and that also keeps my coax runs short and simple. I'd love to have an inverted L but I have no room for radials anywhere near where I could put one up. I thought a random wire would be simple way to get up and going and then go from there. There are some good internet resources that tell you what lengths to use for random wires so that you avoid even multiples of half waves on the bands that you're interested in.

Thanks,
Chris

So what exactly is the unun doing in this installation? Is the coax counterpoise also your feed line?

Thanks everybody, I appreciate all of the help.

Thanks Mike. So you're using a unun and a balun, with the unun at the feed point and the balun right at your tuner in the shack? A current balun? How do you run your counterpoise? Parallel to the random wire?

I'd like to put up a random wire antenna. I'm looking for one antenna that will work with a tuner from about 3MHz (for MARS) or even 1.8Mhz up to 10 meters. Since I am not going to make the wire length longer than 1 wave length on the lowest frequency I intend to use, I think what I want is a random wire antenna and not a long wire, correct?

I have a Yaesu FT-897D with an LDG AT-897Plus tuner. The tuner is attached to the radio and has a coax output connection. I think an auto tuner right at the feed point is ideal but that isn't going to happen. From my reading some sort of balun or unun is required. LDG states that their 4:1 voltage balun is fine for a random wire antenna, yet most of the web "experts" recommend a current balun or a unun. I've seen 1:1 and 4:1 current baluns recommend as well as 1:1 and 4:1 ununs recommend. So, which one is it?

Also, it looks like the ground (coax shield, or ground from balun) should either be connected to a ground rod, a counterpoise wire suspended above the ground, or a radial system. I'm confused here also, which one is correct?

My understanding is that if I don't get the balun/unun and counterpoise/ground right then I could have quite a bit of RF in the shack.

Thanks,
Chris AK4SK