915MHz LoRa Antenna with SMA Male Connector for Meshtastic LORA32 915MHz ESP32 LoRa OLED Board + 15cm IPEX Extension Cable（2 Sets）, Eifagur

Was struggling with the stock antennae for my heltec v3’s and decided to take a gamble and buy this 2 pack. The vna dipped right at 906.875 on the first one with a 1.088 swr and the second was a bit lower at 1.2:1 , but still a respectable match for my needs on such a cheap antenna.

I put these on my VNA and both were near-perfectly tuned at 915MHz; the SWR was almost exactly 1, and just above 1, respectively. Bending the elbow caused a radical hike in SWR, but they're fine for vertical applications.These inexpensive antennas have a reputation for being improperly tuned, so I recommend having a VNA available.These work well on the Meshtastic LongFast frequency of ~908MHz.

The antennas I got - both of them - show SWR over 4 - yes four - in the 900mhz band. They appear to be tuned for 360mhz, and seem also functional in the 800mhz band, but are NOT SUITABLE for transmission in the 900mhz band.**Why is this bad**: SWR is a measure of how much of a transmitted signal is broadcast into the air versus how much is reflected back into the transmitter. Transmitters generally don't like having power reflected back into them. At an SWR of 4, over 1/3 of the RF energy is bounced back to the transmitter. Generally, for safe transmission, an antenna should have an SWR of 2 on the frequency one wishes to transmit on.**Why this is worse**: Most users don't have a Vector Network Analyzer or RF power meter to check SWR, and most LoRa modules don't automatically check SWR. The average user buying this antenna has no idea that it is gradually killing their LoRa module if they're using it to transmit. I literally got a NanoVNA yesterday on something of a whim and was going to test this antenna by the time honored process of FAFO, I am glad I did not.**Defect or Error?**: Other users show reasonable, even good SWR figures - I suspect I was shipped an antenna for the wrong band. It is not marked what frequency it is designed for. But, from a radio's perspective this is "sorry what we told you was water and gave you in an unlabeled bottle was actually poison". The antenna I was shipped is potentially damaging to transmit with, and most users wouldn't know that, and it really can't be known without specialized test equipment.**Bottom Line**: If you have a VNA sure try your luck maybe you'll get shipped the correct antenna. If you don't, buy an antenna with the frequency clearly labeled on and spare yourself the cost of a dead transmitter module. Whatever I was shipped, for 915mhz, it's worse than garbage because -- I can make a far better antenna out of garbage. In fact, I will attach a photo of a far better antenna literally made out of garbage.

These whip it real good. (Eg. They work)

Out of the test antennas tested at 908 mhz, one has SWR at 1.2, the other at 2.1.