The BIG and SMALL ANTENNA topic part 1

(Jens) #332

Hello @Charles, nice to read you! :slight_smile:

The SCGWs are build by @SekiTakakazu in our com. .

Hoping the same like you he transmits his knowing in our infrastructure. :smile:

We have an Homepage, Forum, Wiki and Git. We use Gitlab (decentralise it). :stuck_out_tongue_winking_eye:

And sorry, it is in german for the people that use the german language. But not only!

For a quick talk we have made an channel on “Matrix” (dezentralised and FOSS). If you wana talk? All people are welcome! You find it at: .

Why not Slack? Kommercial an centraliced. :stuck_out_tongue_winking_eye:

And sorry for the offtopic. :innocent:

Have a nice Sunday and do what you want.


Tante Edit: If you want com about email? Eat this : :smile:

(Remko) #333

The problem with F-connectors is that

  • they are 75 ohm.
  • it is difficult to weather proof them with tape

Its better not to use them in a 50 ohm transmission circuit but it might be acceptable under spcific circumstances.

(LoRaTracker) #334

Not sure I have seen an antenna for 868Mhz, with gain, that can receive boht horizonatally poloarised and vertically polarised signals, do you know of one ?

(LoRaTracker) #335

If you have access to program an Arduino board which has the bare RFM9x or DRF1272 LoRa modules, then you can use a pair of them to test your own antennas in real world situations, its really very easy.


(Sönke Brix) #336

Hi @Charles,
first of all thanks 4 ur pcb design. They make a start so much easier :wink:
I used the code from Andreas Spiess, who forked your code. He added some parts like the display and other things.You‘ll find the stuff here:
I had one issue using it. It seems there’s a bug in the 2.4.0 version of the ESP8266 Community software. Switching back to the 2.3.0 solves the problem.

(Jens) #337

Hello @LoRaTracker

For a longer time i found an antenna for american BOS-Funk (4xx MHz) thats look good for me. But doesent find the link.

For now i mean an Cloverleaf Antenna is a good solution for us.

Found a side who describes to DIY this antennas (with calculator for frequency).

Lower at the site there is a link with more information to build it.



This weekend I ordered this antenna along with 5m of H155 high quality, low loss cable.

Can’t wait to see what it will do with my range :slight_smile:


Liquid Electrical Tape

Tape is never optimal for weather/water proofing.

More suitable for weather/water proofing electrical wiring and antenna connectors is Liquid Electrical Tape:

(LoRaTracker) #340

I was aware of the cloverleaf, developed by IBcrazy for use in FPV for radio control models.

A good choice for a transmitter, although it has no gain as such, but its not advised for the receiver I thought.

In the DIY article you linked to it says;

It is not the ideal receiver antenna however, because the reverse polarization rejection pattern is very erratic. You need to choose other types of antennas for the receiver such as the skew planar wheel (4 lobes)

The similar skew planar migh be better suited for a receiver, not sure how well it then performs as a transmitter.

Worth experimenting of course, but these type of antennas are very low gain, I would assume most gateways would want to be using gain antennas in order to increase their coverage for the majority of nodes which will be static.

(Jens) #341


I know. But our LoRa-Modules have very good RF-Parts (~150 db).

More gain? I mean every FullGW should be recieve every message from the nodes in his reachingarea from every position (horiz/vert/diag).

More gain. Hmmmm… :roll_eyes: In some cases it would be an good solution. But in my opinion i am not that meaning. Why?

Have a closer look at an omni antenna with 0 dBi

That antenna recieves all transmissions from every side like an globe.

Antennas with higher gain concentratet there energy in one direktion

But now, what is with the nodes under ore over the antenna???

Some datas for dBi vs aperture
Omni with 12 dBi Gain has an aperture about 7° degrees
Omni with 15 dBi … 3,5°
Omni with 18 dBi … 1.8°

When the nodes are all in the same line and hight, cool. But when not???

Ergo. We need more GWs with antennas that transcieves like globes to cover the areas.


Source of Pics and info about RF for me :
And for this:
Sorry, german only.

(Ebreyit) #342

I ordered the same, just arrived. not had a chance to test mine yet though. waiting for the RAK831 to arrive so I can hook it all up.
Looks very good quality and arrived quite quickly

I’ll be ordering some LBC400 ExtraFlex to go with mine

Both MSDist and Solwise do a cable making service in the UK with LMR400 equivelent cables

(Jens) #343


11mm diameter!!! How will you fit it to the SMAplug???

Adapter??? Then you have getting cheaper cable. Everery connection costs dB. :-/



not all off course.

there are plenty of omni antennas with a higher gain in all directions, well mayby not from the sky

(Jens) #345


Sorry @BoRRoZ : Fake :stuck_out_tongue_winking_eye::smirk:

The physics for (Omni)antennas all the same!

More gain = more directional



show me an antenna that has multi polarisation and gain in all directions that is affordable and can be used on a lora gateway then :sunglasses:

(Jens) #347


YES! Thats the problem. :slight_smile:

Here in Germany we called “Eierlegendewollmilchsau”. Perpetummobilae?

I dont know. I am not a constructor for antennas or a RF-Secialist. but i read many, many sites for that theme. Fascinating.

We must find the best solution for our specs. And an producer that builds this antennas.


(LoRaTracker) #348

And of course if you drop the use of antennas with gain, and use ‘globe’ types for gateways instead, you would need between 4 and 10 times more gateways to give the same coverage.

I am also not really clear why there is a need to track birds and moles …


antenna design is a very complicated specialist ‘business’ …

(Ebreyit) #350


They make SMA’s that fit that diameter cable.

Nice low loss figures @ 868MHz and no need for adapters.

The cable I get made up will be SMA one end and N-Type the other for the antenna.

This is one previously made for me by MSDist which I use with WiFi gear.

(Jens) #351


Are you using your Smartfone under a transmission tower??? :sunglasses: