I've created my own companion from a Heltec V4, battery and a JCG402LR-1 SMA 868MHz antenna.
I live in an urban setting and there about 4 repeaters near me at 2 km distance according to https://meshcore.co.uk/map.html.
Here's my settings:
Frequency: 869.618 MHz
Bandwidth: 62.5 kHz
Spreading factor: 8
Coding rate: 8
Transmit power: 20 dBm
Repeat mode: off
I tried broadcasting an advert (flooded) but I didn't get any responses.
I went to the repeater (50m distance) and checked for nodes near me, and didn't find any.
Messages in the test channel don't pop up.
Ok, so I thought maybe the additional antenna is faulty.
I've replaced it with the stock antenna and drove around some more and found repeaters at 25 - 50 - 100 km who popped up in my contacts.
I didn't expect my companion w. stock antenna from inside my car to be able to pick up signals from so far away.
Because I was driving I couldn't send a test message but did see some messages from the public channel pop up.
So where I'm at now it seems that my additional antenna is faulty.
My stock antenna can pick up signals from 25 km but it can't pick up signals from repeaters "near" me ~ 2km.
This seems a bit mystifying to me. Any ideas?
EDIT: it may be unclear from the OP but I'm running this as a companion, not as a repeater.