Glass fiber antenna 3dBi is not good

Issue:
Hi all, I tested to compare this antenna 3dBi


with small antenna attached with RAK2247 module

When I put same distance node and gateway board (about 1m) then small antenna show RSSI from -28 to -31 while fiber antenna show -70 to -80. Why glass fiber antenna is not better than small one.
Setup:

Server:

Details:

You cannot conduct meaningful tests over such short ranges.

There’s a fairly high chance that in the weak case, what you are actually seeing is the receiver being overloaded and detecting the signal on a different channel than it is actually being transmitted on. Typically it will also be received more strongly on the correct channel at the same time, but allegedly there are situations where it would not be.

If you want to do something meaningful, put the source hundreds of meters to a few kilometers away.

Of course another possibility could be a problem with cabling/adapters, such that the “better” antenna is not actually getting connected to the receiver.

1 Like

Dear cstratton,
I implemented testing with long range. I only archive about 400m. But I found that when I change fiber antenna to rak811 then i get better range and rssi at rak2247. My concern do we need change any configure at gateway side with fiber antenna? I saw in 3 location:
/opt/ttn-gateway/packet_forwarder/lora_pkt_fwd/global_conf/global_conf.eu_433.json
/opt/ttn-gateway/packet_forwarder/lora_pkt_fwd/global_conf.json
/opt/ttn-gateway/global_conf/global_conf.eu_433.json
“SX1301_conf”: {
“lorawan_public”: true,
“clksrc”: 1, /* radio_1 provides clock to concentrator /
“antenna_gain”: 0, /
antenna gain, in dBi */
antenna gain default is 0 dBi. what does it mean? do we need change suitable with dBi of different antenna?
which file is correctly?
thank and regardss,
Tuyen

Dear all,
anyone else to help?

thanks,
Tuyen

@hairuitao
As for Fiber Glass Antenna, there is no better performance, do you have any suggestions?

Wait correct me if I am wrong, however this is lorawan, so a couple of dB gain more or less mea s jack s…
The most imports thing would be that your antenna is well matched so don’t loose a ton of the output power. Seeing how the fiber glass antenna has a decent VSWR, atleast mine does asi measured it with a nano Na, there should be no such bad performance degradation, right?

Hi Hobo, I can’t clear clear your mean. My project need distance over 5km. But my tested in the field is so short only about 400m, even though used fiber antenna for rak2247. So what can i do in order to archive long range? Or I missed any configure for gateway?

thanks,
regards,
Tuyen

To attempt to bridge the language gaps here I believe @tuyenpham has TWO antennas for his RAK2247:

  • The small iPEX coil antenna (that shipped with the board)
  • And a RAK Fibre Glass antenna

When he swaps over to the Fibre Glass antenna, he sees a drop in performance.

First three questions - where are you in the world, what frequency are you using and what is the frequency of the fibre glass antenna (from the label on the antenna) please.

Next two questions: what cable are you using to connect the fibre glass antenna and where is it placed? Pictures would be preferable.

You should see better performance from the properly connected & mounted fibre glass antenna straight away without any changes to the config.

For 5km line of sight, the antenna will need to be at least 2m off the ground - but always preferably above all large buildings in the vicinity - or at the top of them.

Thanks Nick for bridge,
First three questions - where are you in the world, what frequency are you using and what is the frequency of the fibre glass antenna (from the label on the antenna) please.
===> My fiber antenna is 433MHz, I took a picture
image
Next two questions: what cable are you using to connect the fibre glass antenna and where is it placed? Pictures would be preferable.
==> I am using ipex to sma connector
image
I can confirm my connection is good, because I also tried with another 433 antenna, performance same as coil antenna. This is kind of antenna i tried
image

thanks,
Tuyen

Two questions missed.

And one more

Bit hard to tell from the picture, but you have a uFL to SMA showing and then an SMA to N-Type cable to the antenna? Can you check the pin on the SMA connector is still in place?

Thanks Nic,
I come from Viet Nam, so using 433MHZ
I put gw above 3m, gw in the room and node in the car. Is it must LOS between node and gateway to archive maximum distance?
I found my problem, it was wrong ipex to sma cable. Just used another one and can expand to 1.3km. will test more to check

Tuyen