Re: Now that coastal Chipworks is gone


While on the subject and I'm away from my home PC, what does direwolf use for PTT? Just a GPIO pin?
I haven't used it yet, but want to try.

On Aug 10, 2020, at 14:13, David Ranch <rpi4hamradio-groupsio@...> wrote:

Hello Tadd,

I am comfortable that Direwolf works slight better in some conditions, in 1200 Bell 202 and 9600 G3RUH modems, than the NinoTNC, but only if you get it set up correctly, but I’m pretty sure the 9600 is difficult if not impossible to get working with the $5 sound card, unless things changed again. 

I don't believe Direwolf AX.25+soundcard poses any really *different* level of difficultu for packet than a TNC (AX.25 + sound-like device).

The $30 NinoTNC is easier to operate.    

I think the Nino TNC is a great TNC but since you're asking/stating:  Why is it easier to operate compared to say any softTNC?  I think this is really more like an apples or oranges discussion but here are some responses:

  • switch configuration to select 1200, 2400, 4800 and 9600 baud. 

Direwolf, UZ70HO soundmodem, Kamal Mostafa's minimodem, Tom Sailer's Soundmodem, etc. support some of these modes as well.  For the rest of this discussion, I will focus on Direwolf since I know it better than the other soft-tnc solutions.

  • It’s a USB KISS TNC
Why does the physical vs. virtual interface matter but a soundcard can use USB too.  Adding a USB to serial adapter for serial-based TNCs is also trivially simple.

  • It has hardware loopback for testing,
Not sure what this means but with Direwolf+Soundmodem, you can do the same with audio loopback plugs on a soundcard.

  • a TX-TEST button which generates a convenient 990hz tone while
Sending a mark/space test tone is supported in Direwolf

  • keying the radio PTT through the built in Opto-Isolator
Direwolf+sound device is possibly more of a DIY effort than say a complete product like the NinoTNC but adding a opto-isolator to a Direwolf setup is completely possible to add.  I usually recommend people to just use the EasyDigi kit for $9 which also adds isolation transformers for those people who don't need to go faster than 4800bps.

  • a DE9 connector for hooking up a common TNC-radio cable
Adding a DB9 connector to interface to a TNC cable is completely possible by the operator

  • can do site to site link testing with two NinoTNCs even if the host computer is completely screwed up. 
Not sure what the use case is here since the computer needs to ultimately working for the solution to function properly

  • The LEDs on the NinoTNC as well as front panel TXDELAY and TX LEVEL controls are awfully handy.  
Direwolf+soundcard supports LED indicators like DCD and CON.  Being a more DIY project, adding an LED off the PTT circuit would be fairly simple.  Considering tuning pots vs. a I2C configuration parameter vs. a Direwolf configuration file parameter all seems about equal in my eyes.  Being open source, you can modify the code to look at a variable resistor POT through an ADC to set these values vs. use a config file.  I personally don't think this would be a worthwhile effort as you usually set it once and leave it alone for the life of the deployment.

How much comfort and simplicity are you wiling to toss out the window for $25? 

Well.. you can look at it the other way.  How much work are you willing to gain:

   - No additional hardware required if the radio has a built in soundcard and PTT support
   - Built in APRS digipeating, APRS-IS Igating, APRS-TT support, full APRS packet decoding, extensive APRS filtering support, AGW API support, TCP-KISS support, Bluetooth support, GPS support, connected mode AX.25 support, Connected mode ax.25 digi support, SDR compatibility, external inhibit support, multi-bit packet repair functionality, passall support for partial decode support
   - AX.25 v2.2 support
   - FX.25 support
   - other modem support like PSK, QPSK, etc
   - Software can be replaced using existing hardware to use other tools like WSJT-X, Fldigi, MMDVM, etc. for extreme flexibility


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