I am using these Adafruit LoRa radio microcontrollers: M0 radio paired with these parts to make up the antenna system: antenna connector cable

And for some reason I am unable to get much further than 50 meters away before I am out of range. When I use a simple 3 inch strand of wire to create an antenna, I am able to get about 200 meters of range. These parts appear to be compatible with each other, but I am obviously missing something here.

I have double-checked that the connector is soldered to the board by doing a continuity test from the connector to the end of the coax cable, and there is perfect continuity. I will post my entire code if it's helpful, but I feel at this point it is something hardware related because the simple 3 inch whip antenna somehow works 4 times better than the purchased antenna.

Here are the important sections of the code:

#include <RH_RF95.h>
#include <RHReliableDatagram.h>
#define RFM95_CS 8
#define RFM95_RST 4
#define RFM95_INT 3
#define RF95_FREQ 915.0

RH_RF95 rf95(RFM95_CS, RFM95_INT);
RHDatagram manager(rf95, SERVER_ID);

void init_radio(void)
  pinMode(RFM95_RST, OUTPUT);
  digitalWrite(RFM95_RST, HIGH);

  // manual reset
  digitalWrite(RFM95_RST, LOW);
  digitalWrite(RFM95_RST, HIGH);

  while (!manager.init()) 
    Serial.println("LoRa radio init failed");
    while (1);
  Serial.println("LoRa radio init OK");

  if (!rf95.setFrequency(RF95_FREQ)) {
    Serial.println("setFrequency failed");
    while (1);
  Serial.print("Set Freq to: "); Serial.println(RF95_FREQ);

  rf95.setTxPower(23, false);
  • $\begingroup$ Are you using the same antenna polarities (vertical vs. horizontal, etc.) and ground plane (or lack thereof) in all cases? $\endgroup$
    – hotpaw2
    Jul 18 at 21:10
  • $\begingroup$ I have both antennas vertical. One of them is about 2 feet from the ground, and the other is about 6 feet off the ground. Will that make a very big difference? I can try and get them on the same elevation and see. $\endgroup$
    – MattG
    Jul 19 at 1:01
  • $\begingroup$ You might want to add those details, and any other differences, to your question. Those differences in antenna positioning, and ground counterpose, could be significant. $\endgroup$
    – hotpaw2
    Jul 19 at 2:44
  • $\begingroup$ Hello and welcome to ham.stackexchange.com! $\endgroup$
    – rclocher3
    Jul 19 at 13:35

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