Meshtastic

Tbeam with SX1262

Anyone experienced working with TTGO’S newcomer?
I just ordered the Tbeam with SX1262 but we might to add another board type to Meshtastic then!
It’s for 868-915 MHz and hooks up a Neo6M.
https://m.fr.aliexpress.com/item/4001286458852.html

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Nice find! That’ll become the preferred board I’m sure. Also has reverse polarity protection.

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Yeah! Great that the screenprint now warns for polartiy and on this board version 1.1 the 2 amps monolithic fuse has been replaced by a mosfet. A red LED is added on io4.
Also, by looking at this 1.1 board (i’ll have to wait 2 weeks until it arrives) it seems, if we solder the display onto the I2C lines, this LED and the blue charging LED are no more visible as in previous versions (but so wasn’t the gps LED).
Think I’ll order a second one, found out that Liligo is also selling a TTGO Tbeam 1.1 + gps N8M + SX1262 !
Can’t wait to test things out, now I’m getting a bit along with PlatformIO.

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What are the differences with the sx1262 chip versus the “unknown chip” with the label TTGO-868/915MHz-modle: LORA32" that is on my T-beam T22_V1.0 boards ?

I found this comparison to the sx1276/1278 but don’t know what is under the TTGO label
http://www.ebyte.com/en/new-view-info.aspx?id=303

Edit: I counted the pins on the v 1.0 board … it has 8 pins on two of the sides. in what I think is an RF shield over the lora chip ,

Edit 2: I found schematics of t-beam and sx1262-t-beam but it doesn’t help much
see module HPDTek series v1.1 HPD16A_830~945MHz (referred to as U22)

Edit 3: I think I found some answers at this forum…

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Supposedly ttgo is sending me a few. When they get here I’ll add support (it will be a very quick and easy add)

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From a ‘radio’ point of view… all I can find is two subtle differences
sx1262 has better frequency stability and add support for lora SF 5, and different lora data rates up to 62.5Kbps@ xx.

Oh… yes I ordered two just for fun !

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The sx1262 Rx sensitivity is much better also (which is probably a big win).

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hello ac8dg

The “unknown chip” labelled Lilygo Lora32 on your version of the Tbeam 868/915 will be SX1276. For a 433 MHz board it would be a SX1278.

See my regularly updated excel sheet of Meshtastic compatible ESP32 LoRa boards where I just added the new SX1262 based T-beams. So you can compare all existing hardware versions.

Note that, for the SX1262 T-beam, from Liligo’s T-SX1262 datasheet i can’t clearly deduct whether the HPD16A contains onchip 433 MHz compatible output matching circuitry, as the chip label sticker mentions it’s a 868/915 version.
From graph nr 7 one could assume there would be 2 different versions, though: HPD16A_400~520 and HPD16A_830~945MHz, which would be logic for good antenna matching.
Online Chinese translation could confirm their operating frequency range is between 400 and 945 MHz as the SX1262 has this wide band operating range. But, for now, I can only guess if there is a remark in this datasheet saying ‘use 433 MHz version with 433 MHz sticker’…
So I have forwarded the question to LiliGo’s engineers.

Also inserted a new column in my spreadsheet for the SX1262-version of TTGO’s Lora32v2 (T13_V1.6 with T-SX1262 or HPDTeK’s HPD16A in the 830-945MHz version) after I read an older post in TTN’s BigESP32+Sx127x topic i had missed out. Never seen one of those for sale, though.

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Just ordered a couple of these: LILYGO®TTGO T-beam V1.1 SX1262 LORA 868 / 915MHZ ESP32 WiFi Wireless Bluetooth GPS Module NEO-M8N IPEX 18650 battery holder.

Hope they arrive before the end of time! My last order took a little over two months.

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I just received (a couple of the first?) TBEAMs with SX1262. They are really nice (and thanks to TTGO for gifting them to me :grinning:). I’ll be including support for this board in this week’s device release.

The SX1262 is much nicer than the 1276 based radios that are on most of the existing boards. Much lower power consumption and better receive sensitivity (which should mean longer range). It also has a TCXO which should mean better frequency stability. (datasheet here)

I added the support so we now dynamically probe for the radio, so there is no new “board type” in the build. Instead we first try to talk to a 1276, if that chip doesn’t answer correctly we then try to talk to it as a sx1262. We can do this for any of our supported boards, but for now I’ve only turned this on for the TBEAM 1.0 (and later) boards.

Once someone who is not me reports success with this new board, I’ll probably change the recommended board on the website to be this version of the TBEAM.

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these modules look gorgeous

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I found SX1262 version of the T-Beam V1.1. I leave the link below

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I have each of sx1262 on order, the neo-6m and n8m versions.

They are listed ’ Despatched to overseas (Country code: US) ’ on 11/08/2020
which is August 8,2020 . Hopefully they will arrive in the 5 to 8 weeks, so
I expect them by October 1.

I will be anticipating a firmware release that supports these :slight_smile:

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I received two of them today M8N and sx1262 868MHz.

I flashed device-0.9.2 and have android-0.9.04 and successfully integrated them into my mesh with two Heltec devices.

I left them outside and got a gps fix in about 20 minutes.

Nice, except that I broke one display while soldering. I broke the bottom left glass corner and now every second line is dead.

Also the signal strength is only at 80% while on Heltec it is always 100%. They are all in the same room. What a pitty, i bought them because of the better signal overall. Soon my Moxon antennas will arrive, and I hope it will get better. Could not do a range test yet, still printing a cases.

Greetings

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It would be ideal to measure their power with a spectrum analyzer to see their real power compared to older TTGOs.
In theory they should be more powerful and more sensitive than -147dB. I don’t have them, so if someone can run tests with a Spectrum analyzer it would be nice

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hmm - where were you measuring the received signal strength (SNR)? From the heltec or from the other sx1262 board? I’ve noticed the heltecs “center frequency” is a bit off so they might not be optimally receiving from non-heltecs.

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@TitanTronics unfortunately I do not have access to a spectrum analyzer.

@geeksville
Hmm, on the two Heltec all devices show 100% while clicking through the screens. On the t-beams all devices show 80%.

I also noticed that the names are toggling on all “device screens”. Is this behavior expected?

BTW, how do I properly name the devices? My procedure is always to flash the device, pair it all with the same phone and give every node a separate name. One after the other. After that all devices are in the mesh and then I connect a second phone to one node to test text messaging.

But I think the names are not really applied, and a bit confusing both in the app and on the screens. Some are the same name and some an old name.
In the message tab within the app the names are correct so far.

Hmm in that case I bet the problem is just that we are possibly not calculating SNR correctly on the 1262. If someone could put a GitHub bug in for this it would be great.

To measure their power, a RTL-SDR TV stick with the antenna included would also be enough. You can put the two TTGOs close to each other and a meter away from the antenna and you can send a message to each of them looking at the difference in power between them with SDR-SHARP. But I’m sure the SX1262 will pull out 22dB ~ 158mW. the old TTGO transmits around 18dB.

I don’t have them for the moment, but I will order a two of them to compare their transmission power and their difference, to better see their real power

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A post was split to a new topic: Setting/displaying node names