I think you told me a few days ago to use a TXCO if I am limiting bandwidth to 31.25.
How can I start contributing to the documentation?
Our entire website is built straight out of GitHub.
Make a fork of that for yourself, edit your fork and submit the changes back up.
Nope not me, my expertise is antennas (like the Sirio) i not responding to other hardware unless i know what talk about. You need user Costo who talk about TXCO.
Sorry I quoted you by mistake. I’ll tag you in a new thread about antennas.
done and stored as issue 1081
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my TTGO v1.2 “T-Fox” boards have a DS3231 onboard along with pads to utilize a 1w lora module
Can you please post some photos?
Also, what frequency and antennas are you using?
Thanks
I do not know the TTGO v1.2 “T-Fox” board but I know the DS3231.
It is a RTC that is used to keep track of date and time and usually a CR2032 battery is onboard so the RTC is always powered.
DS3231 has no connection with the LoRa radio it is a I2C device on the I2C bus, just like the OLED and the PowerControllerChip.
So I do not believe that the T-Fox TTGO is ‘better’ than the normal T-beam for use with a Bandwidth of 31kHz unless it has a TCXO.
it looks like it is almost pin compatible with the v2 but throws a critical fault error, I’m assuming because of the DS3231 hanging on the bus… lower most board GitHub - Xinyuan-LilyGO/TTGO-LoRa-Series: TTGO Lora Test code. I’m trying to source the higher power modules since I have two of these boards, SX1262? the modules soldered on now are these HPD13A 868MHz|SX1276 Wireless Transceiver Module LoRa|100mW||HPDTEK|Air Conditioner Parts| - AliExpress
update… so did a bit of digging and the HPDTEK module used on this board is pin compatable with the HopeRF RFM95W, looking at their site they have the larger RFM95PW which I see matches with the pads on this t-fox board… has 27dBm @868/915
have two RFM95PW modules on the way… working on a functional build for these v1.2 boards “may need a lil help”
think it’s worth it? It seems like I bought the only two of these boards on the planet and are vaporware now. But if we can find more they would be cheap and optimal candidates for extra long range applications. here is my original amazon purchase https://www.amazon.com/gp/product/B07VQHVT3R/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1
But it’s not a 1 Watt module right?
the 433Mhz modules are good for 30dBm “1W” but the 868/915 are 27dBm “500mW”
I am porting my Compact Lora Messenger which Optimized RF Design for Maximum Coverage to meshtastic right now (loramessenger:project [Unit Engineering Wiki] ). I want to design a very thin device with PCB antenna which fit into the shirt pocket. With 14dbm TX power and PCB antenna, I got 1.5km coverage in the urban area.
Ps. I do have a question about the firmware. It seem the Lora RF band had to be specified at compile time, is it? Is it possible to configure the Lora RF band with the APP in future? I am planning to design a compact device for travelers which supports all bands with max 2W TX power and only one PCB antenna.
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The bands are defined at compile and then selected by the user on initial configuration.
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Thanks for the confirmation. Changing the RF bands in runtime is a small niche demand for global travelers which enables the device to meet regional regulations. For most users, there is no such requirement. Therefore, I am working on the US and EU bands credit card size device right now. 
I still plan to implement the single antenna (PCB helix‐loaded whips) with full bands support RF front end (433Mhz, 868Mhz and 915Mhz), after finishing the LDMOS based high power PA design, I plan to push up the max TX power to 2W to 5W. Could be few months later. 
I will continue to update the design progress~
We should talk about amplifiers. I have successfully attached a 6W PA to a tbeam with support for bidirectional signals.
I’m also holding back a device firmware change to support external amplifiers. If you’re planning on this, we should discuss some time. I could be convinced to put the change in sooner. I have some ideas on some device logic to support this but am only marginally familiar with US regulations (I’m not a lawyer) and nothing about other regions.
I did not find out the post about your 6w PA testing, do you have a link to it? According to what I know, if we want to insert a PA in the TX signal link without modifying the circuit (Of course, no need for code modification), two circulators are required, refer to the Fig.1 [1].
The major disadvantages are additional insertion loss causes by the circulators, the device’s size and weight will also be significantly larger.
After finishing the porting of my credit card size device. I plan to start to design the PA edition handheld device. The LDMOS PA will be placed between the Lora PHY and the RF switch. For the firmware, the major difference is how to control the RF switch, since almost all high-power RF SPDT switch requires 2 logic PINs for controlling the direction (Almost all current Lora design adopted SPDT switch with only one control PIN). This minor difference should not be a problem.
I am not going to choose GaN Fet but LDMOS for PA design due to the cost limitation. I finished the first stage PA design few days ago. For the first stage, the Input 1dB compression point will be around 17.125dBm. According to the load-pull data, the output power will be 34.462 dBm with 47% Power added efficiency (Fig.2).
Reference:
This what I used:
Cheap, very small and works well. I used two antennas for the proof of concept.