Hi, i’m not sure i’m in the correct topic.
I’ve a sonoff 4ch pro R2 with a problem: i can mount it only in one location, and this location is out of router range cause a big enforced wall (in italian: cemento armato) block the signal.
If i install about 1 meter away, all is ok, signal is ok. But I can install only in the first position 
So i need to install an external antenna with a 1m wire to cover the signal.
I’d like to solder an IPEX connector to my sonoff.
The problem is that 4ch pro R2 has not a pad for solder a ipex connector. The old R1 has it!
I’d like to know if someone know how to and where I can solder a connector for an external antenna…
Thanks
you could try a passive repeater, then you have no connection to the Sonoff ,
verical dipole ===================vetical dipole
length of coax
if you are using 2.4 GHz , the dipole length is 6.25 cms , coax if its only a couple of meters
RG174 , you can make the dipole out of the coax.
if its more than a couple of metres use better quality coax.
you want 3.1cms of the inner core and 3.1 cms of the braid, just push the braid back
and feed the inner through the braid so you have a ttal length end to end of 6.2 cms.
Do the same at each
Place one dipole close to the Sonoff and the other where toy have plenty of signal.
It does work, its been widely used for filling in dead spot on cellular networks
HTH
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Hi thanks for the reply but i don’t understand a word
I don’t know nothing about dipoles etc…
I appreciate your answer but it is not in my knowledge.
I’ll prefer, if someone can help me, to solder and ipex connector to my R2.
Pic in attachment
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Ok
If you really want to solder on the board
you need to fit either a RP SMA connector or MMCX as close to the capacitor that feeds the antenna on the board.
Check the under side of the pcb to see if there are tracks below the antenna, it should be clear, but you cant see from the piccy how many layers that pcb has got, At least the components in that area look to be 0603 , 0402 smd is very fragile.
If that ids not understood I respectfully suggest until you have the required skills to work with smd you are liable to do more damage than good,
HTH
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I’ll give a look at pcb.
If i don’t find anything I think i’ll downgrade to R1 version that has the place for connector. Thanks
If you use what I suggestef in the first place, you dont need to solder anything in it, dont need to downgrade, just do a bit of googling so you under stand what I wrote.
It will cost you a couple of bucks for a piece of coax, and you dont need to connect it to the unit, just beside it to work.
very simple school boy stuff
the instruction were given on measurements of the ends of the coax,
Up to you
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With respect @richard-g8jvm I can’t follow your instructions either, although I am interested. Could you give something clearer? Or perhaps a link?
I’d like to try it but if you can send an example link/image of the final expected result… Cause i don’t understand how it works 
thanks
Btw this is a zoom of the antenna. Behind the pcb there’s no way to solder anything
OK I’ll make one up and upload a piccy , I’ll just do one end.
there are many ays of making a dipole ,
sticky copper tape, cut to length , soldered to and stuck down on a piece of plastic.
that can be bought from garden centers as slug tape. two pies of wire.
Or if you are reaaly out of range of your router, I’ve a friend down in Texas who sales
printed log periodic antennas, , they cove both 2.4 and 5GHz.
The principle of a passive repeater is as old as the hills.
You receive a signal where there is good signal strength , pass it down some coax and retransmit it from another antenna.
Useful for getting TV signals if you live down in a valley out in the sticks, point one antenna at the transmitter and one at your location.
AS for the board, you will have to use coax, DO NOT just try a piece of wire it wont work, from the end of C34 (inner core ) and the pad immediately above.
DONT use anything larger than RG 178 coax or you will rip the pads off the board, cut the track to the antenna , so it no longer used, and at the far end of the coax, dont go longer than 2mtrs, make a diploe out of the coax , or some copper tape , or get one of Kents log periodic antennas.
Dont forget extending out side of the casing the braid of the coax will be at the same potential
as the board…
The far end to make a dipole is EASY
strip back the outer of the coax 6.cms.
Push the braid back so you get a large bump of it at the end by the edge of the outer covering.
Carefully make a hole in the braid and pull the inner through the braid,
then stretch the braid back out and out the inner at right angle to the coax and the same but opposite for the braid.
Trim both braid and inner to 3.1 cms, so the overall length is 6.2 cms
---------------------------- ------------------------------
3.1cms || 3.1cms
||
|| coax feed
LH is the inner , dont strip the insulation off it
RH is the braid
You can either make a diopole each end and use inductive coupling to the original, plave the
dipole next to the case , but not in contact.
Or if you really must solder the coax on to the board , put the dipole at the other end where you know you have signal…
Dipole come from latin di means two and pole
I’ll make one up and upload a piccy
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Friend, do you think you could be a little more careful about you proof reading?
I could go on. It is kinda translatable, but one day someone is going to search the forum for vertical dipole and miss you post because of the spelling.
Above all, thanks for the howto, I did some googling in the meantime and sort of got an idea, but your input helps!
sorry
OK my answer is pretty useless., probably comes in the same catagory of all the posts in mutiple languages
This video can be usefull? (apart measurements)
Heres a piccy of the dipole made from coaxial cable RG178
Note the size of the soldering iron tip, you dont want anything larger than that if working on 0603 or smaller SMD component.
And using rework flux helps
Simple and low cost, the squres on the cutting bord are 1 cm
and if you want something at VHF around 150MHz by the look of it.
There is a big difference to what you can get away with at microwave.
If you want to use wideband log periodic antennas which will cove both 2.4 GHz and 5.6 GHz
Kent makes some excellent antennas, beware of copies on e-bay.
https://www.wa5vjb.com/products1.html
You can make wide band passive repeaters with one each end, one pointing at the router where you have a good signal and the other end pointing at your dead spot where you need a wifi signal , but is screened by solid walls etc
You can use the same type of passive repeater to give cell coverage in cellars etc.
HTH
Richard
BTW I have no financial gain from these antennas , I know Kent as a Friend.
Any performance specifications available? What sort of improvement (in signal strength) could one reasonably expect from a passive radiator?
I’m tempted to make the dipole antenna (from coax), walk to the periphery of my property’s 2.4GHz Wi-Fi coverage, prop up the antenna on the ground like a tiny tree-sapling, then use my phone to report signal-strength near, and away, from the passive radiator. Anything you suggest I do to improve the results of this proposed experiment?
While your phone can still see the router you wont see much difference.
The best place to use a passive repeater is where you have a RF hole.
A cellar for instance where you have a good signal from the router outside, but when you go in to the cellar/basement it disappears.
Then if you put one antenna where it can see the router signal , and the other where there isn’t.
you will then find there is signal in the cellar/basement…
A dipole has 2.1 dB gain over an isotropic radiator , so with one each end you can compensate for some of the cable loss…
An isotropic radiator is just a quarter wave length piece of wire mounted vertically above a ground plane.
.If you wre to make the dipole out of some coax used on the feed from sat dish the loss is much lower…
That uses a foil outer for the braid and just a thin wire to keep the continuity, if the wire over foil is not enough to make the other half of the dipole , just wrap some bare copper wire around the foil outer and use that.
So if you plant one end in the ground make sure the coax leaves the dipole at right angles to it and about a meter above ground.
Then find a spot where you have no signal from the router , run the coax to that spot with anothe dipole on the end , and you should have some signal.
A lot depends on the loss of the coax , at 2.4 GHz the thin stuff is lossy 100 feet of RG178 losses about 50dB.
The coax I use on 2.3GHz is LDF5-50 , that 7/8" diameter, solid copper braid and the inner
is 1/4" copper pipe. and the loss on that on 100’ is 2dB
You should for your experiment if you plant one end where there is signal, and the other end where there is none, see some signal on your phone when near the antenna ( dipole).
Anything else just ask, playing with RF is my speciality
HTH
Richard
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Thank you Richard, I have a few Sonoffs in the cusp region, I appreciate your assistance, and can accept the odd typos that were complained about. I will be making one or 2 of these units tomorrow.
OK Patrick
if you just place the dipole along side the sonoff there should be enough coupling.
There are a lot of commercial passive repeaters in use.
The is one on the elevated section of motorway near me, where the motorway is well above the houses beneath and around it, enough to block the signals from the local TV transmitter.
So there is an antenna pointing at the TV transmitter and three antennas pointing down at the houses.
have fun with it
Just a foot note
I’ll be installing one to cover a RF hole at the back of the house, it didn’t matter up to now, but now I have automations running wich relying on the phones connected to the wifi, if my wife goes in to the garden HA thinks shes gone out
There are two solder points enclosed in a rectangle near the on-PCB antenna trace. The top connection is to the ground plane. The bottom connection is the core/positive/antenna signal. Look closely directly above C36 and C10. If it were me, I’d cut the antenna trace near the edge of the board, scrape the paint from the connected portion of the copper trace, and solder the core of your coax onto there. Solder the braid to any nearby exposed ground plane.
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