My RV Portable station and troubleshooting in the field

[Moleculo]

I went camping last week in the RV and took along a radio. I was hoping to put up the coil loaded dipole I made, but the park ranger came around and told me I couldn't attach anything to trees after I got the rope up in it. It's a private campground, so you have to go by their rules. Well, I have a couple different portable HF antennas that I took along also, so I figured I could just unhook the CB antenna and mount those there. Here are a few pics of the simple station. You can see that I used the coax from the CB that runs under the chassis and just extended it over to the table. Sometimes I bring all the digital stuff, but not this time. It's not much to look at, but here it is:

I found out something interesting on this trip. I have the mobile CB antenna attached to the ladder on the rear of the coach and have the ladder grounded to the frame. SWR measured at the radio was about 1.5:1. When I decided to use this mount for the portable HF antennas on lower bands, I couldn't get the SWR under 2:1 regardless of which antenna I used. That told me something fishy was going on. I did some quick ghetto campground tests and found the problem: The ladder isn't providing enough path to ground. When I bypassed the ladder with the jumper cables, everything worked great. I guess on the 11m band the coax shield was also helping to provide enough counterpoise to make it present a low enough SWR to the radio, but that flaw was quickly exposed when I tried to go to lower bands. I bet the CB will work a lot better, too after I fix this permanently Here are some pics of the antenna install and the campground temporary fix:

 

[CamoRedneck]

Awesome

 

[hookedon6]

yep, a short vertical on 11 meters is bad enough, but on HF it really can become a major drawback. the "other half" of the antenna was missing until you jumpered to a good ground

 

[Moleculo]

What's odd is that the ladder provides a metal path that i attached to the frame with the ground strap. However, the ladder wasn't providing the path to ground, for whatever reason. If I attached the jumper cables to the ladder and frame, it didn't work. I had to go directly to the mount. Whatever the surface of that ladder is made of, isn't helping out my antenna install :angry:

 

[mackmobile43]

I can see your cb radio providing a ground path via the mounting bracket to the seat bracket to the frame thus giving the coax a ground path but as soon as the coax was disconnected all ground was lost.

 

[hookedon6]

What's odd is that the ladder provides a metal path that i attached to the frame with the ground strap. However, the ladder wasn't providing the path to ground, for whatever reason.

i can't tell exactly what metal the ladder is made of. perhaps brushed alum or stainless steel. i think it has a coating to prevent oxidation and it insulates it from ground. have you put a VOM from the ladder to ground (with the braided ground strap and the coax dis-connected)?

 

[Moleculo]

have you put a VOM from the ladder to ground (with the braided ground strap and the coax dis-connected)

It's been quite a while since I did the original install (2 years?), but I seem to remember putting a VOM meter from ladder to ground first to see if the ladder was grounded. I'm pretty sure that's why I put the ground strap on. Perhaps I never tested it after that with the coax disconnected. In any case, I'll need to get some more ground strap and extend it all the way to the mount, which should cure this problem for good.

 

[Happy_Hamer]

I think it is horse shit that you cannot run a wire into a tree, but rules are rules I guess, just be a bit more "sneaky" next time.

 

[KI4MSJ]

I have the same setup that I take wherever I go. Right now all my gear is in my footlocker and on it's way to Iraq. I received my Iraqi Amatuer radio license and looking forward to catching up with my gear in the next few days. I also sent along my Buddipole and Buddistick along with my 102' dipole. Looking forward to operating in Iraq