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Author Topic: Electrical Box for radial connection?  (Read 1263 times)
K0JEG
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Posts: 669




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« on: August 04, 2012, 07:41:45 AM »

I was picking up wire for radials on a new telescoping 31' vertical antenna when I noticed the metal junction boxes on the next shelf over. So I picked up a square box and 4 romex connectors, one for each side. I then put spade lugs on all my radials and connected 4 each to each side. I then took a short piece of wire and connected the whole thing to the ground side of my 4:1 unun. The unun box is plastic, so I set the base of the antenna on top of it, the unun on top of the junction box and spread out the radials.

Here's a picture, without all the radials, but you should get the idea...
https://docs.google.com/open?id=0B8dALljET_kMMUFUaUxpek5zakE

I plan on using this antenna portable, and for testing I don't have a very good spot to attach (something I still need to work out) so I strapped it to the pole of a basketball hoop in the parking lot of the apartment building. Using WSPR I was able to hear stations from all over the world, but I didn't seem to get out at all. The tuner found a good match right away, so I think it's working, but the 8' metal pole I was using as a support may have been coupling too much.

Anyway, the question is, does the electrical box work well enough at RF or should I pick up/build one of those dedicated plates with all the screws around the circumference?
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N3JBH
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« Reply #1 on: August 04, 2012, 09:55:51 AM »

I would think a plate made from aluminum would offer better electrical properties.  Now buying versus building that is up to you there. I make them kind a things myself. However some folk's don't have the toll's to do that work in a easy to build fashion. But i think your idea would still work. Also with just the 8 radials you could make just a simple plate that hold the balun and one stud to attach all the wires it be both simpler and much smaller to make.
« Last Edit: August 04, 2012, 09:58:57 AM by N3JBH » Logged
K0JEG
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Posts: 669




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« Reply #2 on: August 04, 2012, 10:16:44 AM »

I would think a plate made from aluminum would offer better electrical properties.  Now buying versus building that is up to you there. I make them kind a things myself. However some folk's don't have the tool's to do that work in a easy to build fashion. But i think your idea would still work. Also with just the 8 radials you could make just a simple plate that hold the balun and one stud to attach all the wires it be both simpler and much smaller to make.

Thanks. There's actually 16 radials, I just put 8 on for illustration. I thought of doing something with an aluminum plate and drilling a bunch of holes, but this was dirt cheap and I figure worth trying. I'm going to try setting up in a park this weekend and see if it performs any better.
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KB4QAA
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« Reply #3 on: August 04, 2012, 03:24:01 PM »

Fifteen years ago, nobody had ever seen a fancy stainless steel radial plate with dozens of holes and bolts.

As mentioned, aluminum would be better.  Copper plumbers tape is ready made with holes!

Soldering or clamping to a larger piece of copper wire is fine.

Those fancy plates are a convenience, nothing more.  They don't improve performance a wit.  No need to spend +$100.

Radio Shack has an aluminum project box for about $4.   I drilled holes and added screws and some wing nuts to use it as my attach point for the radials on a portable antenna.
« Last Edit: August 04, 2012, 03:25:49 PM by KB4QAA » Logged
K0JEG
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Posts: 669




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« Reply #4 on: August 05, 2012, 08:06:51 AM »

Fifteen years ago, nobody had ever seen a fancy stainless steel radial plate with dozens of holes and bolts.

I was going to make something, not buy. Didn't seem too tough to drill holes, even if they aren't even and perfect.

As mentioned, aluminum would be better.  Copper plumbers tape is ready made with holes!

Soldering or clamping to a larger piece of copper wire is fine.

Those fancy plates are a convenience, nothing more.  They don't improve performance a wit.  No need to spend +$100.

Radio Shack has an aluminum project box for about $4.   I drilled holes and added screws and some wing nuts to use it as my attach point for the radials on a portable antenna.

Good ideas, all. I forgot about the RS boxes. I think I have a few laying around somewhere.

Just to update, yesterday afternoon I tried out the antenna with electrical box in the park. Same results, able to hear OK, but the tuner had a hard time tuning this time (but it did find a match) and didn't get out at all. I then took all the radials and put them all on the same screw as the ground wire and the very next attempt I was picked up by a station in Texas. Background noise came up, along with more signals on the waterfall than I'd seen in a while.

The take-away for me is that junction boxes don't work, don't bother with them. At least I'm only out about $3.50.
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