[Modding] Homey Pro (Model Early 201x) Antenna modification

Questions & Help
,
501

Well, as I wrote, these modifications are probably not a problem. The chance of actually harm anyone or anything are microscopical, but still plausible.
In regards to transmitters, the only way to confirm enhanced antenna functionality without the appropriate test equipment, are the thingies I suggested above.
They will tell most of the truth in regards to the transmitters radiated power and if the antenna modification made it better or worse.
If the antenna works better for the transmitter it should also should have the same effect on the receiver since the equipment work in simplex mode (sends/transmits on the same radio frequency)

But I have a small concern regarding the CPU clock (CPUs software is not my strong suit, however, CPU related radio interference are things that I have worked with before)
CPU hardware has the ability to sometimes interfere with receivers if the CPU clock frequency, or multiples of that comes close to the receive frequency.
But also things such as CPU load (!!!), memory usage and load on other data buses may also make the circuit board to act as an antenna transmitting interfering signals (this is why we have the EMC regulation)
That being said, all of you that have poor coverage, Check your surroundings, do you have any suspicious electronics (i.e. access points etc.)?
Try to move them or temporary switch them off and check if your coverage is better (or worse).
Homey has an internal 1 GHz clock, and that is in the risk zone, frequency is pretty close to 868 MHz.
At the moment I donā€™t know if the CPU and peripheral circuits have adequate shielding to suppress not interfere (make the receiver hear less good) with ZigBee/868MHz.
I think that I have an old analogue cable TV instrument that can measure this potential EMC field in an controlled environment.
If this is the case, moving Homeys antenna outside and above the casing can actually be a good idea since better balance between transmitter and receiver will be achieved.

502

You never know,
I had a friend that many years ago worked at the Swedish Post and Telecom Agency.
One day they got order to track down an illegal transmitter sabotaging the Swedish police:s radio communication. They pinned it down after a couple of weeks or so. The police got a search warrant, and a swat team smashed in the door. But the apartment was empty and no transmitter could be found. How embarrassing, but then the transmission started again and could be pinned down to one self oscillating thermostat in water heated radiator, situated on the top floor of a high building close to one of the sites that the police used for their radio network. The signal was very faint, but close enough to interfere.

Aftermath:
That a totally non electrical component, would be capable of self oscillation rated about 452 000 000 times per second (some 452 MHz or close to that, if i remember it correctly)
This is less than one in a lifetime so the odds of this happening are actually non existing, but it did.

The lessen to be learned here is;
Never unknowingly mess with the Police (maybe not do that knowingly either)
Happy Holidays (preferable outside jail)

503

Soā€¦ only do it knowingly? :smile:

1 Like
504

Iā€™ve already packed my bags and now I live in a burrow with a wombat as my neighbour.
Ah, and my Homey went into a wood shredder to erase any evidence,
Fair dinkum m8, I have an external antenna not an amplifier on a device emitting on a freq approved by ACMA. Gives us a break, will you?
And no, I am not looking forward for any more academic replies nor for any other type of replies.

Back on topic with an update, the antennas z-wave and zigbee addition has been now in place for a number of months with great improvement in communication.
Together with the non-secure inclusion of my Fibaro devices provided on a Github fork by a fellow Homey user (hope police wonā€™t hunt him for modifying Athomā€™s app!!), has made all the difference in running my HA smooth. All my 89 z-wave devices (15 battery) respond as per my expectations. Same as zigbee.

6 Likes
505

But it works also without the antenna mod.
Ich have no antenna mod. 90 Devices , 70% of them are secure an over 50 battery devices.
And everything is fine. :grinning:

And not to forget, there are also FLIRs devices in use. :scream:

506

You are lucky, well done.
I would have never gone into the trouble to open my Homey if I would had same experience.
The antenna was the last resort before dumping Homey back for the proven range of HC2. Glad I did it since I love this device and community alike vs Fibaro HC2.
The insecure inclusion just made things a bit faster, communication was already good.

507

And I started it all. I am ashamed.
At least I have not been arrested yet. :joy::joy:

1 Like
508

I live on the opposite side of the Earth so I canā€™t tune in your Honey but perhaps the guys from ISS can easy pick up the signal when the station is above Germany. Because your Sputnik (Homey) :rofl:

2 Likes
509

Major off-topic: there is a default ifttt flow which notifies on passing of the station :wink:

1 Like
510

I connect a parabolic antenna to Homey tonight. Homey should then be able to control the ISS !

511

And that would be the same I wrote in the same sentence:
ā€œ(maybe not do that knowingly either)ā€

512

That wasnā€™t in your post at first was it!? Or am I losing my mind here? :worried:

Anyways, I like your posts, although itā€™s complicated I think we all learned something from it. :slightly_smiling_face:

513

Well, Antennas are more complicated than they seem.
At a first glance it just a piece of wire, but when you start analyzing what is really happening it gets more complicated.
I am not a particular expert in antenna design, but I am a radio designer so I do know the theory and how to protect the transmitters when the fails.
From the transmitters side side of view, It only cares for optimal impedance and that does NOT automatically mean optimal transmission range.
It just mean that the transmitter wonā€™t break if anything goes wrong. This is a big issue for really large transmitters, since they are crazy expensive to repair.

Then we have the Antenna feeders (or cables) We donā€™t usually call them cables since they are everything but ā€œjust a cableā€.
Each type f feeder has it own pros. and cons. in regards to impedance and attenuation and the same goes for the both connectors that terminates the feeder.
This topic is so big it should probably have its own websiteā€¦

Consider this, when a radiowave propagate it will go in all directions in a three dimensional space,
if you want to double your distance you will need to add +6dB (2x 3dB) because you will unwantingly(?) double your backward range as well, this regards to antennas!

An external antenna will get less transmit from Homey, probably much less than 50% , but you obviously notice that it in some cases it still work better. Why is this?

When designing a radio network, like The Zigbee node network, you ALWAYS have a ā€œlink budgetā€ whether you actually calculate with it or not.
The link budget is usually a document, or at least a list of numbers, considering everything that will affect the radio coverage.
It is actually just a simple formula, often calculated in dBm (dB milliWatt) and since most signal gain/loss are measured i dB it is simply adding or subtracting whatever numbers you have.
At the end the number must be positive or it wont work. t is easy calculate your attenuation from the transmitter on one side to the receiver on the other side and vice versa.

Typical Zigbe parameters:
Transmit Power output
Feeder Loss -3dB
Antenna Gain +3dB
Wave propagation Loss
Antenna Gain +3dB
Feeder Loss -3dB
Receiver Sensibility

If we look at that list, the first number that we should consider doing something about is probably ā€œwave propagation lossā€ and regarding that there are theories.
But you always want to confirm whatever calculations you have done with an actual measurement at the end.
The following known/unknown parameters will also interact with the link budget, so you want to make them as small as possible

Shorter distance
Free line of sight - Less interference with objects (wall, ceiling, furniture etc) since they generate loads of loss.
Less interference with metal objects since they are unpredictable, mostly huge loss but can also generate unstable gain due to reflection. (metallized glas as in some windows)
Clean EMC environment by removing incompatible electrical or electronic equipment (i.e. older LED bulbs, dimmable incandescent light, small switching power supplies as in cell phone chargers etc.)
Shield your network from your neighbors equipment or other nearby radio equipment that you share these radio frequencies with.

Zigbee doesnā€™t really have a powerful transmitter. The bigger Zigbee problem, according to me, is mostly radio interference that limits usable surface area.

Actually, why donā€™t we use the electrical wiring to transmit/receive our data?
Itā€™s already thereā€¦

514

So? What is the final conclusion?
Which antenna is the best for every different frequency that Homey uses?

2 Likes
515

VLT+

2 Likes
516

Well, i donā€™t have a clue how to connect that to my Homeyā€¦ :stuck_out_tongue:

517

especially when the pigtails shouldnā€™t be more than a couple of CM.

But tbh, i think weā€™re getting offtopic.

2 Likes
518

Just wanted to share my experience with antenna mod.

First of all, openining Homey was quite unexpected for meā€¦ accidentally I dropped Homey on the floow, two screws keeping top and bottom half of the dome got broken, and since I heard something rattling inside I decided to break other screws. The thing rattling inside was remaining of the screws, fortunatelly everything was working fine - and I had my Homey open.

Then the antennasā€¦zigbee was easy, the connector on the motherboard makes it easy as a piece of case.

Then the z-wave. Well Iā€™m far from being a soldering master, I really wanted something that will not require manipulating soldering iron inside Homey. And I found these little guys - https://sklep.avt.pl/krokodylek-nieizolowany-mikro-l-17mm-przylacze-lutowane.html (sorry, Polish only, but you can take a look at the photo with dimensions) - micro crocodile connector, small enough to attach to the original z-wave antenna. So the only soldering needed was between the crocodile connector and the antenna, far away from the Homey. Of course to use that you canā€™t completly remove the original antenna - you should leave at least some remainings to be able to attach these crocodiles to it. I personally decided to leave it at least for now.

The third part - the z-wave antenna itself. I experimented with two - the beautiful, dedicated antenna designed fot 868 Mhz, and a basic copper wire about 30-40 cm long. Well the copper wire is ugly as hell, but - at least in my setup - it gave better z-wave range then dedicated antenna. Probably because it just much longer.

So far Iā€™m happy with modification, although Iā€™m still experimenting :slight_smile:

3 Likes
519

Maybe you can share some photos?

520

Sure.

These is how crocodile connectors are used to attach a dedicated 868Mhz antenna to the original Homey z-wave antenna

20191217_234936
20191217_2349361920Ɨ1080 185 KB

20191217_235017
20191217_2350171920Ɨ1080 180 KB

This is my experiment - antenna made of copper wire (I bought a standard electric cable and extracted the coper wire from it)

20191217_235226
20191217_2352261920Ɨ1080 181 KB

20191217_235329
20191217_2353291080Ɨ1920 75.6 KB

(the red and blue things on the wire are isolations - I didnā€™t want the antenna to touch anything inside Homey)