DIY external antenna for gateway

Thanks for comment !
i’ll try with more loops and check.

Colinear Antenna @ Zurich
let’s find out how much the difference counts


bad results. back and using the original one

back to the original and a great success: 30km in line of sight!
thanks[] for your great work with that page


@ursm : 30Km that is a very nice result. My compliments.
Could you tell us something about the test setup? for example :

  • which model gateway do you use.
  • what kind and model antenna is the original antenna.
  • is it a indoor or outdoor antenna?
  • what kind of node do you use.
  • what kind of node does the node use.

Looking at you’re diy antenna and you’re comment on the bad results.
Could you give me some info about it ?

Looking at the picture it’s mounted against a pipe. Whats the material that pipe is made off?
What kind of coax cable did you use, what is the length and how did you mount it to the antenna? (do you have a close-up photo??).

I know that are a lot of questions but it may gives me a lot of info about potential problems in the design.


IMST-880/USB & RasPi sponsored by (@gonzalocasas)
-> Gateway @ Zurich (FFFEB827EBA00A83)

it’s no longer available, but I wrote to the store, if they would probably sell it again
and it’s installed outdoor, sealed with shrink tubing over the connectors
EDIT: could be a replacement

It’s a 5meter, 50Ohm cable (swiss shop) with SMA connectors at both ends.

Antenna - cable: SMA connectors
The antenna itself is mounted in a 3D printed block ([quote=“lex_ph2lb, post:25, topic:3011”]
Looking at the picture it’s mounted against a pipe
The colinear antenna was created with the suggested infos from you (handwritten notice). made of “stretched” copper wire and for the test just temporary taped at a white PVC tube.

my LoRa Gateway Locator, selfmade board with Teensy-3.2, RFM95W, u-blox GPS and OLED display

I assume you mean antenna? -> 5dbi antenna


these tests were made with great help of @HanspeterH from funlab and @gonzalocasas
published on the awsome page TTN Mapper @jpmeijers
I hope I could answer all questions to your satisfaction


Antenna Mount (contact:

Coverage 30km


Thanks for the information @ursm.

After reading you answers I can’t figure any thing out why a clear point-to-point connection can’t be made.

For testing I rebuild the antenna again according to my design and tested it. The only thing I could do to make it a bit better is, making the top segment a little shorter and adding a closed loop on top of it for a better SWR.

:warning: 2017-10-01: see further below for a correction of the lengths and new test results.

New lenghts are : 175- 345 and 315 mm.

So : Connector - 175 mm - first loop - 345 mm - second loop - 315 mm - top loop.

Close-up of the top loop.

SWR measurment result
The SWR plot of the new antenna (looks better then the previouse version).

Note : the small light line is the SWR line of a J-Pole antenna experiment.

My current experience with the first antenna is good. Because the installation point isn’t that high, the urban area (concrete, steel, high buildings etc) is putting his influence on the coverage. Using the TTNMapper I started to extend the map of coverage of my gateway (see : link )

hi @lex_ph2lb : we’ll give it a second chance when the new connectors arrived.
probably also with that nice top loop :innocent:

Keep me posted and maybe the top loop will give his blessings :wink:

IMPORTANT NOTE : When I build the antenna I used a cable which I would use to install the antenne outdoor and mounted the for testing on a wood kabinet it was almost perfect. Installed at my home and connected to my gateway it seemed to work out fine (on long distance slightly better RSSI).

This evening we where testing the 2 antenna’s I build and found out that the antenne design is highly effected by the length of the cable and installation style (using a metal tube to mount it to, metal roof underneed etc). We used the same antenna with a 1.5 m long cable (same cable type, connectors etc) and it shifted 5Mhz up.

So there is rework to do in the design.

So I will modify the LAB indicating its a experimental antenna which is unstable at the moment. When people want to build a outdoor antenna, go for the simple ground plane or read this topic on how to use a indoor antenna outside.

Keep you informed.


Have you tried adding a quarter-wave ground plane beneath the antenna?

Didn’t tried that. But it could help indeed. Still have the antenna laying around somewhere.
Wil give it a try,

Well it should help to make the readings more reliable and repeatable as it references the coax shield at the base. Good reading.

I am in Malaysia Lumpur and I can find stuff on lazada or in the market called Pudu plaza. That area has many electronics shops and a few shops for RF and antennas :slight_smile:

does this work for 915 mhz?

lightning protection?

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no more activities on home made antenna at the moment

@jangeirnaert please read my post from 16 august 2016 above.
The design has some nasty side effects.

@ursm home made enough but not for the LoraWan area. :slight_smile: Although I have created some antennes specialy for the CH2I LoraMini module (see : Full Arduino Mini LoraWAN below 1uA Sleep Mode )

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ok, seen
I’ll use at the moment the helical antenna with good results. see
long distance tests will follow, when the program runs with downlink and ack too.

The BIG ANTENNA topic part 1 :sunglasses:

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