Z-Wave External Antenna

I am wondering if there is such a thing as an antenna that can bring a zwave signal into a closed area.

By way of example, I built a control box for my pool. It is all controlled by zwave wall switches which in turn control contactors. Thats the easy part. It works reliably 80% of the time. There are times when the command to turn OFF for the night is not completed presumably because the switch did not get the signal.

The enclosure is a stainless steel structure with multiple louvers for ventilation. I can control it with SharpTools fairly reliably, although I do notice a short delay in switching. (Less than 3 seconds)

Im wondering, if like done with cell phone boosters in cars, there is a way to bring that Zwave signal into the enclosure.


I have seen magnetic mount Zwave antennas but how would you connect one to the switches or a repeater for that matter. It’s going to be tough. That metal box is killing the zwave signal coming in. You would have been much better off using ABS plastic as I use on my 4 outdoor access points. I even threw a Zigbee and Zwave pocket socket in each one to cover my entire yard with both. How far is it from your nearest Zwave device that’s a repeater? Maybe add a pocket socket in an outside plug or something as close as you can get to the box. I’m no expert so I’m tagging @JDRoberts he would know if there was anything like an antenna you could use.


Thanks Michael.

My first one was plastic. Those relays tend to get hot, so I needed the ventilation. It was the best option i could find for what i wanted to build. I do understand that plastic is better for allowing the signal through, but this is what i have to work with.

I already have a GE wall switch on the covered deck about 30 feet away and multiple other switches and plugs that are further away on the far side. My furthest repeater/Switch is in the Chicken Coop about 300 feet from the hub. Everything back there is rock solid. I figure plenty of signal “passing” by the pool box. If i could just direct it into the box. Like I said, I’m thinking along the lines of how they bring the cell signal into a vehicle. They don’t actually connect to the phone, it just captures the signal outside and broadcasts it inside. Maybe nothing like that exists for zwave…

As @michelp said, the best thing is to swap out the enclosure for one made of plastic. Preferably not blue plastic, which, for some reason, seems to block signal more than other colors. You can get a ventilated box if it’s needed.

Absent that, although there are some people who try creating an add on antenna, it’s important to understand that the length of an antenna is based on the frequency being transmitted. If you just make the antenna longer, it can result in a less effective signal so the short answer on that part is no.

You might be able to cut a window into the side of the enclosure nearest the Z wave device and put a plastic insert there and get signal in that way. That’s a common approach for metal doors. :thinking:

Since you have signal in the area, just making one side of the box plastic might be enough.

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Hi JD… thanks for weighing in. I appreciate it. I do understand the antenna length issue, which is why I wouldn’t try to make one, and maybe why i can’t find one …

I suppose I could look into cutting out a side and silicon in some clear plexiglass.

Let me know if something else pops up!!!


I have fans that are built into my access point enclosures that turn on when it reaches 100 F.

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I actually bought a computer fan but didn’t need it with the current box. I’m a firm believer in “simpler is always better”

For what it is worth I have a Fibaro Double Switch 2 inside a 3/16” thick steel safe and have never had any issues whatsoever, although it is not used daily. The Fibaro and some others have an external antenna that could possibly be located outside your enclosure. But would need protecting against damage.

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Could you move the z-wave switch into a plastic outdoor electrical box attached to the outside of you SS enclosure?

I thought about it… this project came out really well and I really wanted to keep everything inside.

Right now my “solution” has been a rule that checks 15 minutes after I expect an ON or OFF. If it is opposite what I would expect, it tries again. I have this do it 3 times. So far I’ve only missed a few triggers. I prefer it get it right every time!

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Another thought…

Are some switches better suited for this than others?

Reason I ask is I have some GE switches 350 feet away from the hub in a greenhouse, (yeah, not a stainless steel box), I’ve never had a problem with them. I got a bunch of these Jasco switches for 20.00 each, presumably because of the black paddle. I will use them in places like the coop or greenhouse where it doesnt matter. JD may have some insight to this. This is what is in the pool control box.

All the GE zwave switches are made by Jasco (as are several other brands, including Enbrighten without the GE logo). But different generations have different ranges. Basically each new generation got better in that regard.

You’ll get the best range right now from series 700 switches, and I think Zooz is the easiest way to get those, they’ve had theirs out for a while. But any series 700 should give you good range.

(series 800 will be super long range, but you have to have a hub which supports those, and neither smartthings, nor Aeotec is ready for series 800 yet. You can still use the switches because of zwave’s backwards compatibility, but they’ll fall back to essentially the same range as a Series 700.)

That may not help get signal out of a metal box, though. :thinking:

BTW, the other option depends on your exact wiring layout, but it might be possible to put the smart switch either close to a junction box, inside the house, or near the circuit breaker box, particularly if the devices you want to control are on a separate sub branch. That’s how a lot of installations get around weatherproofing issues, but they can also solve range issues. But it all depends on how your wiring runs. Basically, if you could put a dumb switch inside the house to control that device, you can put a smart switch in that same location.

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That’s why I like when you weigh in! That’s not a bad idea. I’d have to put a switch and a relay or contactor next to the breaker box as it is on its 20 amp circuit, on high speed I need 18 amps out there. I don’t think I’ve ever seen a 20 amp smart switch. The other option I thought about was this 40 amp switch. They are about 200.00 and I thought a bit of over-kill. This is where I got the antenna idea.

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Would like to figure out how this antenna works!

It works the same as any antenna, it’s just that they made it straight and connected it at that point. You can see it’s not that long. Most zwave antennas are curled around on the board just to save space but you don’t have to do it that way.

Here are a couple of 20 amp options:

Need in-line on/off switch 120v 20A

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On sale for $100:


So as follow-up to this thread, here’s what I’ve tried so far. Knowing that an antenna needs to be a certain length, I tried this anyway:

The antenna wire on this paddle switch is a very short piece of solid wire right behind the paddle. I extended that wire with a short piece of solid wire and ran it through one of the louvers. That resulted in a 100% failure on triggering the switch. So unles there is another specific length that works with ZWave, I assume I’m stuck with this length. Next i removed the extra wire and just ran the existing antenna out from behind the paddle and towards the louvers. So far this has resulted in only 1 “delayed” trigger in 100 tries.

I created a rule in SharpTools to check the “status” of the switch every minute and let me know if it goes “offline”, which it would quite often previously.

Geting closer to the louver may solve my problem, but only time will tell.

The antenna length for any radio device is based on the frequency, not the protocol.

There are typically 3 lengths that will work: full lambda, half length, and quarter length.

That said, there are a bunch of other factors that go into making an affective antenna, including the materials, impedance blocks, the shape, etc. It’s complicated. :thinking:

Here’s an old but good discussion specific to Z wave on another form forum from a few years ago.

Z-Wave Antenna - Z-Wave - Series 300/500 - Universal Devices Forum.

Thanks JD,
Interesting article… based on this from that article, (Z-wave operates at 908.4 mhz. A vertical omni directional 1/4 wave antenna for that frequency should be 3 3/32 inches long. A full wave antenna should be 12 3/8 inches long.). From that, I’d say the antenna in a paddle switch is 3-3/8" long. It’s definitely not copper, and all the other variables would make this a challenging/impossible project. So far my simple modification has not resulted in a failure today… fingers crossed…

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Are you sure it’s not copper?

You could see if you can remove that wire or shorten it and connect a small diameter coax to it…but then you’re getting into impedance matching and lots of complicated RF stuff.

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