Hello all.
My project contains two devices based on moteino.
one device is "server", it is located outside, under a lot of snow and has several thermosensors.
it has UFL connector soldered to PCB.
UFL connected to pigtail with SMA connector.
to SMA connected feedline - coaxial cable (lenght about 3m) and on other side of cable - N-type connector which connected to DIY GP antenna also based on N-type connector.
another device is "client" and it is portable device which I use to receive data from server device.
it is small case with moteino + ftdi adapter which I connect to my smartphone via OTG cable and get data from server via UART.
client also has antenna, but this is antenna from old broken meteostation.
it looks like monopole antenna but when I disassembled it I noticed that inside it has PCB instead wire.
then I assembled it and soldered pigtail to Moteino PCB. In manual to meteostation stated that it use 915MHz as my LoRa RF module.
I think this antenna is dipole but I'm not sure.
So, this client works as expected - receive data from remote servers. Maximum range is about 5 km.
I have issue with second client device.
it similar to first client but antenna is different:
https://www.amazon.com/gp/product/B01HHPK7KS/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1also I soldered UFL connector on Moteino PCB and connect antenna via pigtail:
https://www.amazon.com/gp/product/B01CWJ5JS4/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1and this client doesn't work as expected. I can't receive data on point where I succesfuly receive data with first client.
I can receive data only if I stay very close to server.
And I think issue with antenna.
I disassembled it, and inside it has wire with spring. Lengh of wire is about 8cm from begining of spring till end of wire.
then I started read a lot about antennas, how they works and about radiation patterns, but still don't understand why first client works better than second.
Seems my new antenna has very low range but I don't understand why.
My main questions:
- do I need install new antenna on metal ground plane? I suppose no, because for example a lot of wifi access points and routers with detachable antennas doesn't have metal ground plane at all.
their antennas just installed in plastic case and connected to PCB via pigtail like I did.
now it just connected to SMA connector and placed in case.
- what exactly name of my new antenna? how it should be placed/located for good working? what is the spring in my new antenna?
- I would like to make good DIY antenna for client - would someone please advice some manual for my needs?
I think monopole antenna not good for my needs, because it shouldn't be used in hand, close to body - I usually put client in my jacket pocket.
Thank you in advance.