Don't forget flux, it will make a lot easier along with some micro tweezers.
2 Likes
I just did my C7. After you solder the u.fl connector be sure to ohm test it to be sure it is open between ground and the center pin. If not, redo the solder correctly. Location of the antenna connector is tricky to locate it so it will not touch the PCB when closed up.
After that, it just works!
5 Likes
That's EXACTLY what I will say when I receive mine after @lewis.heidrick does the mod. 
Impressed w/you other do-it-yourselfers w/this task...too many tiny things and pointy tools at very high temperatures for me to consider. 
6 Likes
I do best at fixing things that respond to being repeatedly thrown against the floor and hit with a barrage of obscenities.
9 Likes
I just did this mod for the zigbee antenna in one of my C5 hubs that I use for only my Aqara temp / humidity sensors (w/ Tradfri repeaters of course). Not that i needed to do this hub but i wanted to practice before opening the C7.
LQI #'s jumped from 140-160 to above 250
Thanks @lewis.heidrick for the write up.
On to the C7 !!
note: I used this antenna for the zigbee
1 Like
I am still looking for the parts that @lewis.heidrick recommended in Canada at a reasonable price. He did not recommend using dual band when I asked, nice to see you are having good luck with it
I used the Bingfu here and they worked fine and the coax seemed well built.
The 900 MHz antenna didn't test very well (75% efficiency) compared to the LCom but it did make a difference. Waiting on my radio tech to have a bit of an order to get the "real thing" and eat some of the $$$ shipping charges.
1 Like
Disclaimer - I am not an RF guy so anything I say may be wrong 
I have read through the 500 posts here and did see @lewis.heidrick comment about dual band antenna. I do think he was warning more about when the dual bands were 900m & 2hz.4ghz as it's tough to optimize for both, with 2.4 & 5g having a 2x difference, the antennas are more aligned. But i could not find a datasheet for the one that i listed above, so who knows what the real gain is at 2.4ghz.
For zwave i ordered this one
https://www.digikey.ca/en/products/detail/linx-technologies-inc/ANT-LTE-VDP-2000-SMA/8020929
Datasheet: https://linxtechnologies.com/wp/wp-content/uploads/ant-lte-vdp-2000-sma-ds.pdf
Also rated for multiple bands, but concentrating on specs @ 915mhz I decided that it was an improvement over the internal and would be good enough to try. Now that I have it installed on my C7 and have it up and running ... it hasn't been running long enough to change any routing but instantly my zwave is noticeably snappier. So far so good.
4 Likes
Added a couple of videos of the process so people can see how I do it in my guide post. Maybe a few less butchered hubs will result. They were shot in 4k so you should be able to see pretty well.
13 Likes
could you point directly at the video link? There's about 100 links on this insanely cool topic and I'm not really sure which one to watch!
Got it for you!
1 Like
Wow...very nicely done.
Thanks for posting those, they remove even the slightest doubt that sending my hub to you will be the correct decision. 
6 Likes
The "trick" I think is to clean the pads and add a bit of solder to ONE pad. Then using tweezers, slide the uf.l connector into the melted pool of solder, as shown. After that, the other pads are nice and stable, flat, easy to complete the soldering and flux clean off.
4 Likes
Exactly
2 Likes
Another vote for adding External Antenna's! What a Difference!
@lewis.heidrick completed the antenna mod described in this thread on my C7 hub and its been running for a little over 2 weeks. I'm using the L-Com Antenna. I only have Z-wave devices and not that many (16) which I'll explain later, but first the results:
With the antenna, every device "included" on the first attempt, typically within ~ 10 seconds, and connected directly to the hub. The only device that hasn't stayed direct connected is a Zooz battery door sensor attached to a metal door, which is also the device with the low RSSI.
Prior to adding the antenna, I needed 3 Aeotec repeaters just to get other devices to connect. With the antenna's, I didn't even include the repeaters as all the other devices direct connected. I was even able to add 2 new devices in my basement surrounded by metal ductwork.
The highest RTT is 3 ms, and only 1 negative RSSI which is the Zooz battery door sensor mentioned above.
The difference is dramatic. Many, Many thanks to @lewis.heidrick !
Some added perspective . . . for those interested:
Before adding the antenna I was ready to give up on HE. Frustrated at how difficult it was to include devices, erratic performance of the most basic automations, etc. I have a <2000 sqft single story open concept home and it would often take 2-3 attempts excluding/including to get a device 10' from the hub to include. I reset the radio and "started over" 3 times trying to find the optimal hub placement, but even with the hub on top of a cabinet, in the center of the house, away from metal and other electronic devices, with a clear line of site to most devices, performance was still weak/poor. From a users perspective, I kept thinking . . . Why can I throw a Lutron Hub in the back of a cabinet surrounded by electronic devices and connect a caseta switch first time in the far corner of my basement, but I can't connect a device 10' in clear line of site to my optimally placed HE hub? (and yes I know the technology is different) I seriously thought the radio in my new C7 was defective, so stopped trying to add devices and after countless hours reading community threads, and reviewing Z-Wave mesh reports, thank goodness I ran across this thread, and Lewis's willingness to help.
The Hub with the external antenna mod now performs as an end user would expect. Devices include as instructed, stay connected, and communicate quickly and reliably (much closer to the user experience of a lutron hub ). I can now work on actual automations as opposed to troubleshooting z-wave mesh.
Oh, and regarding hub placement, I put it back in an enclosed cabinet, with obstructions between the hub and my devices, and still all but 1 device are direct connected, including those in my garage and basement.
IMHO this is a game changer, and the only reason I am still using HE. I can only hope they include or at least provide the ports to add antennas on the C8 hub. This and many other threads could then be devoted to working on actual automation.
10 Likes
I like this approach...HE could still sell a "basic" hub closer to the current price-point, but the hub would be enabled for enhancement if necessary/desired. Hint: HE could sell some "Approved" antennas on the side (with hub or as a later add-on) for additional $$/margin. (Thinking about @bobbyD's retirement fund...)
6 Likes
I would buy a new hub in a heartbeat if it had a better antenna. I have mostly Zigbee devices, but the 20 or so zwave devices that I have are nowhere near as fast. An improvement there would be very nice.
7 Likes
Very much this. The antenna mod is well within my soldering skills, but probably not for many users, and the cost of failure is high. @Ghuntz said this is a "game changer" and I agree completely. A model with external antennas for all radios would be something I would gladly pay a good bit extra for, along with PoE support on board.
9 Likes
It's right near the beginning, in a post by some guy. I think his name was Lewis. It was around post #28
2 Likes
for those of us new to u.fl connectors, do you mind saying a bit more about how to ohm test it? I assume use a multimeter in continuity test mode, but where do I place the probe for ground and should the unit be powered off or on (or doesn't matter)?
