Meshtastic to connect isolated villages

Hah! That’s really good to know @Bunplugged and @Hugobrr thanks. I’ll try removing the chip next time. I’ve already sent them back and ordered new ones, which will hopefully be better (?).

Or you can just cut the plastic in half and squeeze it in.

Just arrived!

Now we can finally build fully autonomous nodes. The smaller pannels are 5W and output 5V, the larger ones are 10W, and will need a controller.

Update: currently looking at these 2A 6V controllers. Looks alright?

The new batteries are the right size and are supposed to be Sanyo 2600mah batteries. How can I test their cappacity? They came with terminals, should I just strip em off?

2 Likes

Energy autonomy test - day 1 :zap:

I’ve been testing a T-Beam with one of the new batteries attached to the 5W 5V pannel.

Charged it to 100% yesterday at 6pm. This morning it was at 33%, no messages actually being sent.

Today at 6pm, the battery was 100% charged by the panel.

1 Like

Did you connect the panel directly to the board and use the onboard charger?
I suspect the panels drain the battery at night if you don’t use a proper charger. a 70% loss in six hours is abnormal.

I had some problems with my ttgo with that setup. My TTGO kept switching off when the charge current was greater than the panel could deliver, But I havent re-tested with the new firmware yet. here has been some power adjustments recently.

I see my TBeam battery drained to 50% in a day depending on circumstances, for example no gps sats inside home appears to drain more then when it does have sats. Also when it is the only active board in the mesh it seems to drain more (more call outs to find another nodes? Is there something like that in the code?).

Hmm. Let me take a look tomorrow, I think we might be accidentally leaving the gps on.

1 Like

If it isn’t too much trouble I think a nice step in the relay node direction is providing more control of on device GPS. An option to use the phone GPS even if hardware GPS is present may be useful, as well as turning GPS off completely.

1 Like

It’s been happening every day since. Charged too 100% with the pannel, and discharged to around 30% by next morning.

@Bussemann

Did you connect the panel directly to the board and use the onboard charger?

Was doing that, but also tried without the board being connected to the pannels at night, and same result.

Besides the possible overuse by the gps, could it mean my batteries aren’t really the 2600mah they say they are?

I bet the problem is a bug that crept in recently. I think tbeams are burning too much power. I’ll investigate/fix later this week.

I unplugged my TBeam this morning, its been 6 hours now and Im at %43. Mine was in a bag, indoors with no GPS at all and no other radios in range.

I can say though the Bluetooth Range is impressive. My bag was in my steel locker and Im at my desk with 2 cynder block walls and a couple of drywall walls w/ steel studs between here to there about 15 Meters away. I opened Meshtastic only to find it was connected and updating the battery levels.

2 Likes

Building antenna and using vector analyzer to test and tune

The N type chassi mount and the sma cables for building a simple ground plane antennas arrived. I followed this video and used a ground plane calculator to make sure the measurements were correct. In the case of 915Mhz all 5 radials should measure 7.8cm. We cut them with 8cm so we can better tune them later.

The Nano VNA v2 also arrived, and by following this and this video, I was able to calibrate, set the right scales and learn to navigate the device, which is much more complex them it seems.

I still haven’t soldered the copper rods to the chassi-mount, as I believe there are still some tuning to do. But it’s been enough to get some measurements from the vector analyzer.

With the factory omni antenna:

If this is calibrated well the SWR is quite high at 3.25, from what I learned it should be bellow 2. There also a logmag which has -46db, but I’m not sure what that means.

With the DIY ground-plane antenna and a 10cm cable:

The SWR is at 1.63 , which as far as I know is ok, and the logmag shows -67Db , which at first seems worse then the factory antenna.


I believe that will get better results after soldering the radials, but still not sure how to use this to tune.

Tips on how to interpret this @geeksville @skyde @TitanTronics @dafeman @Spor7biker ?

1 Like

See if I can find you some info how to calibrate the device and how to measure the antennas correctly :wink:
But don’t go crazy with that device, on youtube there are a lot of people showing how to do it :grin:

(I’m sending you a link in a private message to not incentivate YouTube channels here on the forum)

When measuring the antennas always use the same position and do not touch the antennas with your hands because their reflection changes. You have to measure the antennas inside the house not outside, sett the frequency range correctly
Set the frequency value from - to the one assumed to be right
You should see a hole in the yellow graph where the antenna has its resonant frequency
Deeper the hole in the graph, better the antenna is.IMG_20201005_204022

You will see something like this

1 Like

Thanks for the tips @TitanTronics! Re-watched the video with more attention, and I think I’m getting something closer to expected:

This is with the stock antenna. Well calibrated?

It is my pleasure to help if I can :grin:

You did everything perfectly.
Only one thing to do again, if you look carefully above the yellow graph there is a yellow triangle
that you have to move to the bottom of the hole in the graph
You have to center it correctly so you can read on the right side the values ​​of the antenna, such as the response frequency of the antenna and other values ​​in right way.

(for the return loss it is fine in the upper part but to know the resonant frequency you have to move it to the center of the hole in the graph)

1 Like

Yay :tada: So this factory antenna’s resonant frequency is at 760Mhz? Needs some tuning huh?

2 Likes

Yep :smile:
Except, to modify that antenna is not easy.
You have to open it to change the length of the internal components which is usually complicated.
However, for 868Mhz it is fine even if it would lose one dB in efficiency.
It is better to build an antenna from scratch.
I’ll send you some parameters of 868Mhz or other frequencies if necessary



3 Likes

That’s really awesome. Is that an application? All my devices are actually 915Mhz, so 760Mhz is really off. Would like to get those parameters for 915.

Ordered a nine element GSM 824-960mhz yagi, the 5 elements I got last week was already pretty good, looking at swr and signal amplification, considering they cost 10 usd from China.

1 Like

That’s awesome @PA7John, I’ll look into them for future implementations.

Congrats for the release @geeksville and @mc-hamster. I’m testing out and seems to be working well. I have a few questions:

  • How do I enable the WiFi mode? meshtastic --set wifi_ap_mode true --setstr wifi_ssid mywifissid --setstr wifi_password mywifipsw

  • I have two Rak4600 boards, since it’s an nRF52832, is it supported already? There’s no official build is there?

  • Can I already test router mode? Update the meshtastic cli tool and with the device connected thru usb run meshtastic --set-router.

Amazing work :+1: