Changing frequency on T-Echo

I’m about to receive 2 T-Echos running on 915mhz. Can I swap the antenna and change the frequency to 433mhz in the firmware?

Or is the 915mhz board different from the 433mhz board on a hardware level (except the antenna)?

I have (8) 433mH that got shipped incorrectly and need to get rid of them.

I’m getting mine as a donation by a user of this forum so that i can start fixing bugs in the firmware.

How do you plan on getting rid of your devices?

They cost me about $31 ea. If I could get $15-20 I would be happy. I live in Arizona. Also looking to pay a Meshtastic developer to help me finish setup. Maybe trade.

I’m working on the firmware as a volunteer. I’m just looking for donor devices to fix the firmware for everyone.

As of now meshtastic is a mess on the T-Echo. I have T-Beams to which I’m adding compression.

I’d love to buy a T-Echo but my pocket isn’t allowing me at the moment. I can only donate my time and skills at the moment.

I can surely help you with meshtastic setup but given the fact you have T-Echos, I’m not sure if it’ll work. Do your T-Echos work at the moment?

Let me know if you’d like to help. Cheers!

Originally the setup went fine. I followed the Mestastic Windows tutorial. They are working and communicating. While I was waiting for the TTGO’s to
come from China, I purchased these from Etsy. I think same but no GPS and they were programmed to fairly recent update.

My issues started when I tried to get back to Meshtastic/Python with no luck after many hours of trying. I also had no luck trying to get
the CP210x driver to load/work. A Fivver driver “specialist” worked on it for two hours and finally gave up. Said it might work in Windows 7. I have
Windows 10 as most people and not going there. Today I got another Fivver Python “specialist” and he finally got me Meshtastic back and even
added the new GUI. I think I’m connected even without the CP210x, but not sure what to do as far as changing settings, updating firmware. The GUI looks nice and has these features but not sure how to make them work. You gave me a glimmer of hope when you said the TTGO’s have a lot of problems. I thought it was all me, even as a newbie who has no idea what he’s doing. Send me your address and I will send you two of the
433mH if you think they will help.

The lora radios are frequency specific.

I think, you don’t even have CP210X. I think you have CH9102.

This is a common mistake. I’m quite sure this might be the case in your situation. Otherwise a faulty cable or board perhaps?

I can help you with it over a TeamViewer session.

I’ll send my address in a private message. Thank you.

I did just try “Connect Radio” in GUI and bottom Python lines show-
Maybe connected? The radio screen does show “7b5c”

From the looks of it, something does work. I’m not sure why you’re connecting it to the PC if you only want to send messages but either way, we can setup a TeamViewer session and I can diagnose these issues for you.

Your cable seems fine.

Thanks Team Viewer at your convenience.
There is also the possibility I am connected, but cannot change board settings or update Firmware.
I think both of these functions will be needed at one point.
Are you in EU ? What is best shipper. I will start to look into it.

Sending you a private message.

As I’ve told you before, you need to change the impedance matching circuit on the RF sub-PCB to switch from 868/915MHz to 433MHz and vice versa.
Only 868MHz and 915MHz are interchangeable via software!

I have no clue how to do this. Is it possible with a soldering iron, or are we talking about something too small for a human to do with their hands?

There is no documentation on those LORA modules so you are on your own. Parts are likely 0603-0402 SMD size.

That’s 0402 … I do that by hand with a beer in the other. It’s the width of a ridge on my fingerprint.

IMG_2811 2

If you play with that with a beer in the other hand, then I bow down to you. I can barely solder LEDs well.

Where exactly is that on the board though?

It’s inside that can and if in the can, it’s probably smaller than 0402.

Pigs will fly before I’ll be able to do this :smiley:

You could also try it on the different frequency and see what happens.