Trailer ‘Tenna

We recently retired our old pop-up tent trailer and acquired a small hard-sided travel trailer.  The antenna I used with the pop-up camper evolved over 19 camping seasons to a pretty decent all-band antenna.  It covered 80 through 6 meters (with a tuner) and required almost no space at all when deployed.  I needed to come up with something similar for the new trailer.

My new travel trailer on its maiden voyage to Codorus State Park in south-central Pennsylvania.

My new travel trailer on its maiden voyage to Codorus State Park in south-central Pennsylvania.

For the first outing, I went with a modified version of the Pop-Up Vertical.  In a nutshell, I used a 30-foot vertical wire, fed through a 4:1 unun.  The ground side of the unun was attached to the frame of the trailer.  My 31-foot Jackite pole supported the wire.  I used my drive-on mast support to hold up the pole.  Instead of parking one of the trailer’s tires on top of the drive-on mount, I put it under one of the trailer’s stabilizer jacks to hold it down.

This is the drive-on mount that supported the Jackite pole. The black box is the 4:1 unun. To the left of the unun, you can see the clamp for the ground connection to the trailer's frame.

This is the drive-on mount that supported the Jackite pole. The black box is the 4:1 unun. To the left of the unun, you can see the clamp for the ground connection to the trailer’s frame.

On our first camping trip with the new trailer, I was able to quickly set up the antenna.  For the feedline, I used an 18-foot length of RG-8X coax, which I ran through a window to the dinette table inside the trailer.

Using the tuner in my KX3, I was able to get the antenna to load up on 80 through 6 meters.   The 80M band was a bit touchy but the KX3 was able to get to 1:1 SWR.  I had a nice CW chat on 40M with N1ESZ up in Connecticut.  Tony gave me a great signal report.  This thing appeared to be radiating!  I was a little concerned because part of the antenna was close to the metal wall of the trailer but my signals were going somewhere.

WB3GCK operating from the new trailer. My XYL took this picture while I was working N1ESZ on 40 meters.

WB3GCK operating from the new trailer. My XYL took this picture while I was working N1ESZ on 40 meters.

I made another half-dozen QSOs on 80, 40 and 20 meters over the weekend.  The antenna performed well during some lousy band conditions but I did encounter some issues.

There was some noise that appeared about every 25 or 30 KHz that moved around a bit.  It was loudest on 40 meters.  I suspect that the trailer’s converter, which converts 120 VAC to 12 volts DC, is the culprit.  My antenna was pretty close to the trailer’s power cable that connects to “shore power.”  I could have picked up the noise from there.  Also, during a QSO with KK0I in Wisconsin on 40 meters, I noticed that a LED on the trailer’s control panel was flashing in unison with my CW.  My 5-watt signal was finding its way into the trailer’s circuitry.  The extra amenities and gadgets in the new trailer are convenient but not necessarily radio-friendly.

Not unlike the antenna on my old camper, this will be a work-in-progress.  On our next trip, I’ll be relocating the antenna to a corner of the trailer that’s further away from the electrical stuff.  I also have some tweaks to the antenna configuration that I want to try.  If all else fails, I’ll just have to mount the antenna further away from the trailer.

Stay tuned…

72, Craig WB3GCK

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4 Responses to Trailer ‘Tenna

  1. Dick Barnes says:

    Interesting read. I use pretty much the same antenna as my fixed station antenna … 30 feet of wire on a Jackite pole with a 4:1 unun. The main differences are that I have about 100 feet of coax feedline to a LDG tuner and I’m using a radial wire thrown on the ground. It’s supported by lashing it to a vertical clothesline post. It tunes 80 through 6 meters with about the same characteristics you described. Quite frankly, I was really surprised at how well it does perform. I sort of threw it up as a temporary “get-on-the-air” antenna, and it’s been up a few years now. Nice to know it performs just as well configured as a “trailer portable”.

    72 de Dick N4BC

    • wb3gck says:

      Dick: Yep, I’ve had good luck with this type of antenna for many years. For years, I’ve used a 53 or 58-ft version in an inverted L configuration for Field Day. It has never let me down. 73, Craig WB3GCK

  2. Steve says:

    Just wondering if your ‘led’ issue is related to the fact that the ‘ground’ you’ve used is not actually earth ground, ie your trailer is isolated from ground via the tyres and there there are no earth stakes (or are there?)

    • wb3gck says:

      Hi Steve:

      The antenna is set up on the camper like you would a mobile antenna on a car. I think most of the issues stem from having the antenna near the side of the trailer that houses all of the electrical and appliance-related things. There are no ground rods as that would be impractical for this application.

      However, you may be right about the led issue being related to grounding. I didn’t mention it in the blog post but before we left for home, I removed the antenna’s ground connection from the camper’s frame. Instead, I ran a couple of radials on the ground. The antenna worked fine and the led didn’t light up. The received noise, however, was as loud as before.

      On the next trip, we won’t have access to AC power. The trailer will be running on battery power only. My guess is that the receive noise will be much lower. At least, that’s my hope. The antenna will also be moved to the opposite side of the camper and I’ll be trying a few different configurations.

      I’ll be sure to post an update on what happens.

      73, Craig WB3GCK

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