Zigbee and Z-Wave operate on 2 different radio frequencies. The HE hub has 2 separate radios, one for Zigbee and one for Z-wave. You can potentially modify either, or both, of those radios by adding an external antenna to either or both of these radios. I have only modified the Z-wave radio to use an external antenna, because I only use Z-wave devices. That is, I don't use any Zigbee devices. If I also used Zigbee devices, I would also want an external Zigbee antenna with higher gain.
Since I don't use Zigbee devices, I can't provide much input. I will say that Zigbee can potentially benefit from a stronger RF signal, just as Z-wave does. There are numerous complaints on this forum regarding Z-wave issues, but far fewer regarding Zigbee.
The question is, how much of a difference it makes in terms of Zigbee connectivity and Zwave connectivity.
I think that the zwave connectivity question has been answered.
Before the antenna mod non of my devices connected directly for zwave and most devices routed through 3 or 4 devices. After, all but 4 connect directly.
For ZigBee I don't have details like I do for zwave but it reaches the community mailbox 3 houses down and across the street.
I'm not good at eyeballing distance but I'd guess it's maybe 100 to 150ft from my front door and another 35ft inside the house to the hub. The mailbox is that little silver square just above my truck bed.
I did both because… why not? I only have about 12 zigbee devices and only 2 are repeaters, but I didn’t notice much improvement on zigbee. On zwave though, 3 days after adding an antenna, I previously had 49 directly connected devices. I now have 66. Not perfect, I have 103 devices. But it’s much higher (15% higher) and zwave has been much more stable. This proves to me what I previously thought, the zwave antenna in a C7 needs improvement.
Depending on your layout a different antenna might fit your situation better. If you have a floor plan or something like that I can make a recommendation if you want.
Generally though 5db is a good all around antenna for medium sized 1 to 2 story homes.
3db is good for 2 to 3 story small sized per floor homes.
9db I generally only ever use on large single story or single story with difficult penetration.
In all cases though, placing your hub as close to the middle of your hose as you can will make a huge difference.
@DarellCraighead you had asked in another thread about how to get your mailbox motion sensor working better. See @lewis.heidrick post above about adding a Zigbee antenna to his hub and the amazing range to his mailbox. Something to consider.
I went with the same antennas you used. I have a 3 story (2 + basement) 3000sqft home. My hub is in the basement. The biggest challenge I have is it is NOT centrally located in the house, and I really can't do much about it.
So far though it's still getting better, I'm now at 69 direct devices. That's 20 devices more than before I did this modification and I have 104 devices, so that means a 20% increase. I'm very happy so far.
To get it centrally located you could try something Like me. I have a coax run from where my modem is to the TV in center of house middle floor. I use gocoax adapters to run from the modem to the other location and put a switch behind it. Not sure if that wil work for you or not.
Yea, if it was on first floor you'd probably get all of them. It would be interesting to hear what your relocation limitations are. I'm sure we could find a workaround.
I just happen to have one on eBay right now.
