Adding external antenna to gateway

[Sergegsx]

Hello,
Would it be of any use to add an external antenna to a moteino, kind of like the router have, to increase performance?
Would I see an improvement only by changing the gateway one, or is it necessary to also change node ones to see an improvement?

How to add this antenna to a regular moteino without the mini antenna connector in the PCB?

Thanks

[perky]

Changing the antenna for one with a higher gain in the direction of interest will affect both transmission and reception equally, so the short answer is yes you only need to change one of them to see an improvement. Doing the same for the node will also have an additional gain on top of that in both directions. What won't help is simply increasing the transmit power of the gateway without also increasing the power of the node, because you'd still be limited by the lower power of the node.

If for example you were to put a dipole externally, then you'd need a piece of coax cable with the shield connected to GND and the centre core connected to the ANT output (but make sure these are very short connections, so choose the closest ground pin to the ANT pin available), and centre feed the dipole so the centre core is connected to one vertical arm and the shield connected to the other. Or buy a dipole antenna and wire the coax to the ANT and GND pins as previously stated.

Mark.

[joelucid]

And just to add, the improvement you get by moving from l/4 wire to dipole can be fairly drastic, especially on 433 MHz. On top of increasing signal you can also often reduce noise by moving the antenna away from noise sources like Pi's. So a dipole with l/2 feedline can work wonders.

[LukaQ]

dipole with l/2 feedline can work wonders.

I don't know how that looks like, do you have anything to show me?

[joelucid]

Like this: https://lowpowerlab.com/forum/rf-range-antennas-rfm69-library/rfm69hw-sensitivity-with-standard-initialization-parameters/msg17801/#msg17801

[LukaQ]

Like this: https://lowpowerlab.com/forum/rf-range-antennas-rfm69-library/rfm69hw-sensitivity-with-standard-initialization-parameters/msg17801/#msg17801

That looks to me like you can use coax, solder one wire to shield and other to inner conductor, is that so? what about coax length, is that also fixed to some general length?