External Antenna

While I am no antenna expert, my experience with Radio Frequency (RF) from CB to millimeter wave, is that the antenna being used is hugely important. And bigger antennas are almost always better.

From what I have read, the HE is considered to have a weak and not great antenna. When you take apart your HE C7 hub, you will find a bit of foil on the bottom of the case that acts as the antenna. One for Z-Wave and one for Zigbee.

I have voided my warranty and added an external antenna to my HE (7). By adding a very cheap 5db gain antenna, I instantly increased the number of devices connected directly to my hub, by 30%. This also reduced the number of hops for other devices that are still being repeated.

I suggest that on Hubitats next model hub, they provide for the addition of external antennas. I appreciate that not everyone will want to incur the cost of external antennas, or the looks. I also appreciate that this will result in a very slight increase in the manufacturing costs of a hub to add u.fl and/or SMA connectors to the circuit board and case. Though, I believe the additional cost would be far less than a single Z-Wave device. Finally, I believe that the majority of Hubitat Users would welcome and pay for the better RF performance provided by an external antenna.

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This has actually been under consideration. Thanks for sharing your experience. Did you add external for Z-Wave? or Zigbee?

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Could you provide specifics? Was it optimized (tuned) for a particular frequency?

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A post with pictures of what you did would be appreciated.

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My system is all Z-Wave. I only have an external Z-Wave antenna. Though, due to the higher frequency, Zigbee should benefit even more from an external antenna.

And it would be smaller :slight_smile:

Almost in jest I did a google search on a duplexer for 900mhz/2.4ghz and found this puppy. I envision a whole range of optional accessories!

I am pretty sure that an external antenna port is verboten under FCC type approval regulations.....

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Well, there is an external antenna port on each of my Netgear WiFi routers. :thinking:

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You definitely bring up a good point! A close reading of Part 15 by an expert would be a good idea :wink:

I am not such an expert by any means (and I did not even stay at a Holiday Inn Express last night). There are definitely restrictions on power at the antenna (1w) and effective radiated power (4w). Didn't see any reference to external antennas / connectors though. There are other devices in the ISM bands (@672southmain's router, for instance) that have connectors and external gain antennas. There might also be restrictions in the zwave or zigbee technical speeds as well. But it would sure be helpful if there were not! I'd imagine you also have to be careful not to create an imbalance between send and receive capabilities and make sure one transmitter could not desense the other.

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You aren't the only one that has done this. :slight_smile:

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No idea how good/bad the hub internal antenna are versus the SiLabs UZB-7.... But my UZB-7 connects directly to devices 50+ feet away through 4 walls with no issues. Not sure a large external antenna is really "needed" for the typical ranges we use with a mesh based protocol.

That said, zwave lr could benefit from better attenuation if we start pushing the range. It definitely benefits the range on my LoRa hubs.

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It really works better in my opinion, and it's an easy mod. I would say another 30% of my devices went direct to the hub after this. Simple 900 MHz, 9 dBi antenna. SMA or RP-SMA connector.


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No argument - it is pretty easy to do. And it certainly doesn't hurt. :+1:

"needed" is a subjective word. :slight_smile:

I tried a few antennas. One thing I would note is that high gain antennas tend to fall off dramatically on the vertical. Depending the placement of the hub and the various devices, a standard 3 or 5 dBi antenna may actually give better performance (more direct connections).

Unfortunately I don't have room for full wave antennas, but these 1/2 waves work pretty well. YMMV

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Btw, did you print those brackets?

A review of the posts on this forum has no shortage of people with connectivity (not software) issues. And the responses almost always suggest strengthening the mesh. A better antenna on the hub is just another way to strengthen the mesh.

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Chad. I am curious if you have tried other antennas besides the 9db gain one you mentioned. I am also curious if you happen to have a 2-story home, and if the 9db gain antenna still has enough vertical coverage for a 2-story home.

No argument there. But again, that still doesn't make it "needed". But I'm just arguing semantics now. Better signal is a good thing - so if you have the skills to add the connection/connector (and don't care about the hardware warranty), go for it!

Yep, the brackets are printed! I have a single story home, but its 85 feet from one end to the other, so a better antenna certainly helped. I did try a 3 db but the 9 worked better for my situation.

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