Hi friends! I just arrived in the community and i will make a base repeater for my city on the top of the hill, using the local ham club’s tower. However i was trying to test my Heltec ESP32 V3 just purchased and i have noticed that the output power when transmitting is much lower than the other device i have (Lilygo T3 S3). I put both with exact same configuration in my Spectrum analyzer, and i got the average output peak around 5.6dBm while the Heltec V3 at around -26.6dBm, which is a crazy difference, taking into consideration that both usd the 1262 LoRa chip. The setup was exactly the same, cables, connectors, all the same. Does anyone have any idea of what may be going on? Thanks!!
i bought 3 and they all suck ( thought was another issue ).
how did you measure output power?
I bought a NanoVNA because the internet says its the antennas… and the antennas are all fine. I even used parts from my FPV gear and made an antenna. still can barley get across the yard. How Can i use the NanoVNA to test the output power ?? ( i was thinking the pigtail wires maybe shorted, i am not wondering if they are just poorly manufactured or went thought a test that messed up the radio)
Edit to my post:
1 of the 3 was bad ( maybe is output-ting 10 mW , it can barley get across the yard)
1~2 of my pig tails for my antennas also eat signal.
I had to make my own pigtail and antennas. and test alot.
Do need a way to test output power. like a standard test or some sort.
There are RF power meters that are cheap, just take a look on Ali.
OK, they might not be precision devices, but you can ‘calibrate’ them against a known good working node. You would need some test software that could send out a packet that was a few seconds long.
The alternative could be a standard test where you look at the RSSI of a packet over a short distance, so 50M, in a standard environment. That could just be a large flat open space with nothing around such as a footbal pitch. The transmitter would need a ‘referance’ antenna, which could be an easy build 1/4 wave vertical with radials. Record and publish the packet RSSI at the 50M. The results on a field in Europe should be the same as on a field in the USA. You can also use this method to compare the real world performance differances between differant antennas, no VNA or SWR meter needed.
Trying to figure out if I have this problem or not.
Done some range testing around my neighborhood and got around 5-6km at best. Seem ok to me on a relatively flat area with some obstructions.
Then I’ve done a longer range tests with a friend, around 20km many times where I can rx just fine but not a single message went through from me. Ive done this multiple time and in slightly different locations.
Ive also done this where the other party has an identilac setup to me. With this its the same story. So naturally I’m thinking maybe I have a bad Heltec chip or not getting full tx power.
…or maybe its just a terrain thing? Can the terrain effect the signal that it goes the other way just fine but not the other?
Hi Pedro!
Did you figure this out in the end?
I have a V3 with almost no output power measured using a TinySA.
I don’t know how sensitive the TX is for incorrect load when at full power out. I have managed to forget to attach the antenna a few times while experimenting… Is the 1262 blown if no load is present perhaps?
Hi!
In my case, the radio was really dead. I got another one and all right.
Thanks!
It could be blown.
When ‘experimenting’ its a good idea to keep the power real low.
Thank you for a good advice!
I have a four new Heltec V3s on the way from Amazon and will set the power out low before being sure the antenna works great. I did receive a lot of nodes when my temporary GP antenna connected though so should be able to get in contact with at least a few of them. At least the one 600m from my house. It had a measured SWR below 2:1 which should be quite ok.
I have a LiteVNA to test my antennas with as I plan to build my own.
Bjorn
My best result with Heltec V3 plastic case and 2dB antenna and TX of 20dB was 17km traceroute. Not so bad …
Hi Bjorn, I wonder how you are getting on ? Did you find the problem ? I have a similar problem, receiving many nodes but virtually all Traceroutes and outgoing messages fail. (Unless extremely local) I understand the Tx ouput power should achieve a max of +22dbm (not the +27dbm, as indicated in the Lora Config). However, on checking my module output power on an RF Explorer spectrum analyser, found it to be only -17dbm. (May be higher as there is probably some induced loss through the connecting cables and adapters) So this is clearly a significant cause of my problem. It seems several users have reported this type of issue with the Heltec V3 and like you, I wonder if I inadevertently ran the unit without an antenna connected, (I don’t think so) or is there indeed a low output power problem with some of these modules ?
Hi, after reading this thread, I thought I’d check my Heltec V3 Wireless Stick Lite on a spectrum analyser. The measured power out was +20dBm, and there might have been a dB lost in the coax adaptor plumbing.
I have also noticed that I can see nodes but can’t traceroute them quite often.
So far my longest single hop link is 89km, when there was a slight temperature inversion.
Glenn.
have you tried setting it to ham mode and set output power to 30 ? and measure output?
there was a firmware problem before: very low output on some hardwares, that was solved…
maybe you could try different firmware versions… something older like 2.1 …
i have theree wsl lite here, that perform quite well on newest firmware version , connected to a RAK-pcb antenna (that comes with rak modules)
be sure to have antenna connected to the right ipex connector !? (the “V3-side”-connector)