Welcome, Guest
You have to register before you can post on our site.

Username/Email:
  

Password
  





Search Forums

(Advanced Search)

Forum Statistics
» Members: 108
» Latest member: on6dp
» Forum threads: 39
» Forum posts: 255

Full Statistics

Online Users
There are currently 4 online users.
» 2 Member(s) | 1 Guest(s)
Google, ea5gvk, elms

Latest Threads
M17 Reflector
Forum: Technical
Last Post: ea5gvk
2 hours ago
» Replies: 12
» Views: 1,471
Fragment LICHs
Forum: Technical
Last Post: tarxvf
3 hours ago
» Replies: 5
» Views: 54
M17 abuse mitigations
Forum: Technical
Last Post: tarxvf
Today, 12:08 AM
» Replies: 4
» Views: 119
M17 and multiple repeater...
Forum: Technical
Last Post: md
Yesterday, 10:02 PM
» Replies: 2
» Views: 37
Test and verification dat...
Forum: Technical
Last Post: tarxvf
Yesterday, 08:53 PM
» Replies: 1
» Views: 23
NONCE field
Forum: Technical
Last Post: SP5WWP
10-18-2020, 04:40 PM
» Replies: 0
» Views: 22
M17 - SDR & GNU Radio
Forum: Technical
Last Post: pthrr
10-17-2020, 07:37 PM
» Replies: 10
» Views: 2,431
Distinguishing between fr...
Forum: Technical
Last Post: G4KLX
10-16-2020, 05:28 PM
» Replies: 5
» Views: 93
SYNC
Forum: Technical
Last Post: tarxvf
10-16-2020, 10:57 AM
» Replies: 1
» Views: 55
TR-9 PCB, 4-layer
Forum: Technical
Last Post: SP5WWP
10-11-2020, 01:46 PM
» Replies: 2
» Views: 482

 
  TR-9 gerbers
Posted by: SP5WWP - 07-23-2020, 08:43 AM - Forum: Technical - No Replies

All gerber files are now available for download at our github. I have already ordered HMI and mainboards, 30 pieces of each.

https://github.com/sp5wwp/TR-9/tree/mast.../fabOutput
https://github.com/sp5wwp/TR-9/tree/mast...I/fabFiles

Print this item

  2FA problem
Posted by: F4GRX - 07-16-2020, 11:34 AM - Forum: General discussion - No Replies

Hello, I cant activate 2fa on my account.

I get this error message:

The following errors occurred when trying to save your profile:

    You did not enter your password
    The password you entered was not correct


But I entered the correct password of course. I tried this several times with no success.

Can it be fixed?

Thanks!

Print this item

  "Review (kind of)", ideas and questions on TR-9 hardware.
Posted by: HB9DNN - 07-13-2020, 03:32 PM - Forum: Technical - Replies (8)

Hi everybody,

I finally found some time to read the TR-9 schematic. I take the freedom to comment a little bit on my findings. It is by no means thought as general critique on the concept. Nor is it a formal review as I don't think this is necessary in this stage of the project. So please accept my comments as positive feedback and food for thoughts.

1. Requirements specification
There is no top level requirements specification (at least I could not find anything). I understand that this kind of hassle is very often avoided (also in commercial projects) but I think it is very important. I might be a good idea to shortly sketch the design goals, most important interfaces (e.g. energy sources planned in the design), overall structure of the hardware.
This does not need to be a novel sized piece of art, a few lists and / or tables with requirements and maybe some diagrams are sufficient. This document will grow with the project.

2. Power requirements / consumption
So far I understand this should be a handheld device with limited battery size. Overall power consumption is quite important therefore. Now the definition of "low power" is somehow relative. If You ask somebody who works in the motor driver business he considers everything below a few tens of watts low power. If You are designing a LoRa module with 5 years+ battery shelf life You start to count electrons. My experience with several projects of the second kind taught me that permanent consumers are the ones to concentrate on. I found several possible candidates in the schematic which may severely limit battery life.

3. So lets turn to the schematic. I follow the pages and list (without specific order) my findings and / or questions:

3.1.
a: OS1 is a "low power" (guess You expected the "" :-) ) oscillator. As used here it runs continously so the around 4mA are consumed no matter if its precision is needed or not.  The STM32 processors have a sophisticated clocking unit which, should the external oscillator fail will automatically switch to the internal oscillator (datasheet chapter 2.15). This could be used to save a considerable amount of power. The external oscillator can be disabled via pin 1. If its accuracy is not needed just turn it off. The internal oscillator will take over automatically if needed.
b. USB: The STM32 processor is ready for USB-C. Why not use it? Maybe something to postpone but USB-C is the future: high speed, higher power capability, batteries could be charged through it, etc.

3.2: well. Clearly under construction. May I make a suggestion?
- 2 18650 LiIon cells in series. Charger through USB-C, two DCDC converters for 7.5V (PA, Preamp) and 3.6V to 4V as preregulator for 3.3V LDOs for the rest. 7.5V DCDC converter can be disabled if not used to conserve power.

3.3: 5V really needed? I assume the TFT display chosen may need it, but this could be generated locally with a tiny step up converter.

3.4 Not many questions. I am not the expert on RF power amplifiers. What might be something for a future design is using a class-E design for its higher efficiency. But as we are talking about UHF here this may be just marginally more efficient.
I have a question though about the bias circuit. Does this opamp need 5V or would 3.3V be sufficient? If not could it run from +BATT? (again to get rid of the the 5V supply).

3.5 Audio output. The LM386 is an ancient amplifier chip. Certainly ok of the purpose it was designed for but as an audiophile I shiver from the sound it produces. I think it was Rick Campbell KK7B who first urged designers to use high performance circuits in the audio path. Not because Your squeeking signal will then sound like an opera singer but because it does not *add* further "squiekiness".
Apart from that the LM386 has quite a high quiescent current.
The STM32 used here has a digital audio interface (including I2S). It might be possible to use a class-D audio amplifier chip. Eg. the SSM2518 is a complete stereo amplifier with exceptionally high efficiency. Volume could either be set with a rotary encoder or reading a potentiometer value with one of the ADC channels.
Again maybe something for future iterations.

3.6: just a question: what is U11 intended for?

3.7: Looks like You want Wifi? Why not use an ESP32 in RMII mode? The STM32 does have such an interface and all the logic needed for Ethernet. Again: maybe even further in the future.

4. HMI Board: Is X1 needed at all? (power  consumption). Maybe this functionality could all be handled by an ESP32?

Just a few last notes on the overall structure. I like the fact that HMI is separated as much as possible from the rest of the system. This may allow to operate the radio "headless" through Ethernet in a later stage. I think of using the radio through a web interface (be it over a PC or smart phone) might be a nice use case.

Do You guys already have some experience on EMC problems of the design? What I am missing somehow are shieldings for sensitive parts (e.g. for RX and TX, particularly PA part).
I definitely expect some side effects from DCDC converters, no matter what topology is used. So it might be a good idea to shield the power supply section as well.

A last idea on the protocol: would it make sense to have some slow acting automatic TX power setting (using some nifty QOS data exchanged between the two stations involved)? This may help to keep radiated power as low as possible and additionally conserve power.

Puuh, that was quite a lot of babbling. I hope this was not too wooly and unconnected.

Questions always welcome :-)

Best regards und 73 Robert HB9DNN

Print this item

  M17 & ARISS
Posted by: SP5WWP - 06-27-2020, 08:02 AM - Forum: General discussion - No Replies

We have contacted ARISS guys some time ago. Looks like they might be interested in developing M17 and the TR-9 handheld for ARISS use (with an emphasis put on SSTV and APRS). Take a look at the last page of this presentation. There is a size limit for attachments, so I had to upload it somewhere else.

[url="https://m17project.org/files/download.php?id=34&token=f6mhRSkfy2vSgRIuBrVyEmzqA2LEumBK"]ARISS-I E2E 2020 FRIDAY 26 JUN, 2020[/url]

Print this item

  m17project.org certificate has expired
Posted by: N6NZ - 04-05-2020, 04:02 AM - Forum: General discussion - Replies (1)

Just noticed today.  Firefox has gotten whiney.  Need a new cert. -n6nz

Print this item

  M17 Reflector
Posted by: AD8DP - 02-10-2020, 06:55 PM - Forum: Technical - Replies (12)

Hi,

I'm really interested in this project.  Are there has been any plans for an Internet reflector yet?  I saw the hostpot project and talk about tests sending/receiving UDP frames on Github.  Maybe it's too early for this, but I'd like to add M17/Codec2 support to my DUDE-Star/DroidStar software (details on QRZ) that allows network based RX/TX, similar to BlueDV and friends. It would be a good way to get a thorough understanding of Codec2 and the M17 protocol, before I get my hands dirty and start building some hardware.

-Doug AD8DP

Print this item

  Why is M17 better? -- Maybe it can have RSSI / Power Control information
Posted by: WA4OSH - 02-07-2020, 04:50 PM - Forum: Technical - Replies (2)

I'm really tired of people connecting to repeaters asking for a signal check?  How well are you making the repeater?  Kerchunk the repeater or hotspot should and it should be able to tell you during the squelch tail how well you are being received and your radio should be able to set the minimum needed power out to make the trip at full quieting.

Can those "empty" bits in the voice stream in the squelch tail be filled with RSSI measurements and power control information?

Print this item

  Podcasts
Posted by: WA4OSH - 02-07-2020, 04:13 PM - Forum: General discussion - Replies (1)

I discovered this project through a very interesting Podcast...

Ham Radio Workbench - HRWB093  M17 Open Source Digital Radio System
https://www.hamradioworkbench.com/podcas...dio-System

--Konrad, WA4OSH/7

Print this item

  ADF7021 problem
Posted by: SP5WWP - 02-01-2020, 05:58 PM - Forum: Technical - Replies (1)

Does anyone have mmdvm board and can help me? I have a problem with writing to ADFs registers. I can provide a hex for STM reflashing.

Print this item

  TR-9 Frequencies?
Posted by: N6NZ - 01-29-2020, 05:53 AM - Forum: Technical - Replies (3)

I have been poking around the FAQ's, etc, but can't seem to uncover what frequencies the TR-9 is targeting?  The AD7021 looks like it could hit US ham bands at 144, 220, 440, and 900 MHz. It looks like it just misses the 4m band that some of Europe has. What is the project going for as a first target?

Print this item