Trailer Antenna

It seems I’ll do any amount of work to avoid future work. Go figure.

A good, and very long-time friend, Larry, KC7VX, has a fifth wheel that he would winter with in Arizona. I saw that he had a Hustler 6BTV mounted on the back bumper of his trailer and it worked very well. That turned out to be an expensive visit. I got to thinking about how well his ‘mobile’ antenna worked for him and I was determined to add something to my much smaller trailer involving the Hustler 6BTV.

I already have a 6BTV on my city lot and I have a woefully small number of radials on it, but it works well. One radial per band is the best I could do. Inherently, verticals are noisy because they are hearing things from 360 degrees. In an urban environment it picks up every TV, LED light, solar inverter, and AC unit for miles it seems. I use the home vertical for transmit and a wire antenna for receive. Another story.

Being familiar with the Hustler 6BTV, and the wonderful quality for around $300, I was ready to invest in a second one without a second thought. DX Engineering has a large collection of accessories they make for this antenna as well as a well researched manual with far more information about this antenna as well as some additional measurements that let it work pretty well without radials. At least for a good match. A good radial system is important if you want a correct and well working vertical. The chassis of the trailer seems to do a fairly good job as a counter poise, as most mobile antennas rely on.

I picked two options that DX Engineering had that would make this install work well. First, the new base mast that is stronger than the one that comes it. The idea is that this part continues to get the wind and weather while on the move. The other was their tilt over bracket. I think the idea of the tilt over is for people in HOA (caged communities) and can only let the antenna show up when they are operating and tilt it over when not in use. Both are over engineered and worth what they charge. It was another $300 or so.

Enough background. On with the install. There is a 100% chance your trailer/Fifth wheel is different. So, this is meant to be an example of how I did it with what I had to work with. Look over your own situation and give it plenty of thought. The most important ingredient is a positive attitude that you can come up with something.

This gives you an idea of how the mount works. As you’ll see, I have it set up to tilt towards the side (towards me in this case). I have a better chance to have room that way instead of behind me if I’m at a campground. I could rotate it on the mount to tilt in any direction if the need arose.

I had a receiver mount welded to the frame to hold the whole mess. That was the only outside help I needed. Thanks to Dan, KD7UEX, for his welding experience and time. Good friend and neighbor.

To tilt it over it’s as easy as loosening those finger knobs, lift it out of the slot and tilt it over.

On one image you’ll see velcro straps. I put those on for safety. One keeps the knobs from unscrewing down a rough road. The strap around the post and base of the antenna is to keep it vertical if all else fails.

The black mount is a 2″ flag mount for those people who run up and down the road with big flags on their trucks. (you might be a red neck if…)

I will point out that our trailer is raised so I had plenty of clearance. And, the design of this trailer has the wheels on the outside and not under the trailer. Like I said, each situation is different, so look at your rig and see what might work. I spent a lot of time looking around and scratching my head and letting a plan form. And reform as needed. Long term measuring twice and cutting once in my mind.

One side had no real obstructions along the side. And there are bolts hanging down that are used to hold the wall in place. It is all very solid. I found some 3.5″ clamps for hanging pipes from a ceiling and somehow the actual threads and size FIT THOSE BOLTS. So, I screwed five of them in place and done. That worked way better than I was even hoping. The pipe is 3″ inside diameter and I made it 14.5″ long. Of course that involved a joining ring and I put sewer caps on both ends for access to the antenna. So I can put it in from either end. The 80 meter coil is easy enough to just unscrew and stow in a compartment. Being only 70 years old I’m not nearly old enough to work 80 anyhow.

There is always an unavoidable curve in the pipe as these are not designed for aesthetics. In this case it was another pleasant surprise. The gradual curve actually gives the antenna a gentle snug fit. I was still considering what I might need to do to keep the antenna from rolling around in the tube. Well, problem solved.

Time will tell how well it travels. Hustler builds some rugged antennas. I’ve always found their mobile whips to out perform anything else I’ve tried. (screw driver, ham stick)

I have gone on two trips with it, before I had a nice storage system, and it was more of a hassle to break it down enough to fit in the trailer between stays. But well worth the signals I heard all over the band. It works very well.

The only thing that isn’t optimal is that I sit about five feet from the antenna while it is in operation. Being 70 I have had all of the kids I want, so that doesn’t bother me. (both are hams BTW). I tend to run either QRP or no more than 50 watts. And the fact that it is only when I’m out camping the exposure is not a regular thing by any means. Not as regular as I’d like. So, there is that.

I hope this has inspired a few of you and given you some ideas on how to step up your semi-mobile operations. Let me know what you think.

73

Dave, AI7R

Dave@ai7r.net