Raspberry Pi for Ham Radio – X days Off Grid

Hello Operators

At the time of writing this, it’s just about time to head out on one of the X days off grid excursions. My radio uses a headless Raspberry Pi for digital Communications. This allows me to have the same user experience connecting with my radio, regardless of the tablet or laptop I’m using access it. I very much like the idea of connecting to the radio, so I view the radio and the Raspberry Pi as a single integrated system.

UPDATE

After many requests, I published a video about the Raspberry Pi for Ham Radio.

Raspberry Pi Access Point

Operating from home, my Raspberry Pi , tablet, or laptop all use the Wi-Fi network from home. This is fine when Wi-Fi is available but in the field it is another thing entirely. Before the access point was setup, my interim solution used a 4G Wireless Wi-Fi router to create that Network away from home. Naturally getting rid of the 4G Wireless Wi-Fi was a priority for field work.

My buddy Jordan KN4CRD, sent me this easy-to-follow tutorial. It allows us to set up a dynamic access point for the Raspberry Pi when away from our home network, I’ll explain.

Normally my Raspberry Pi (when operating from home), is accessible to other devices in the same network, from the Wi-Fi access point in my home. That allows connections to it using a VNC client. The tutorial Jordan sent me does a few very cool things.

1. When I’m home, ut attaches to my home Wi-Fi network and bridges it, so I still have internet when I’m attached to the VNC client..
2. If it doesn’t find that Network, which means I’m away from home or the network is down, it creates its own network with the built-in Wi-Fi adapter on the Raspberry Pi.
3. It also creates its own DHCP server to hand out IP addresses to my tablet or laptop, so that I can connect over VNC client to my Raspberry Pi powered radio.

Here’s the link to creating an access point on your Raspberry Pi.

Raspberry Pi System clock update from GPS

Another thing required was a very accurate clock on the Raspberry Pi. Some digital modes are dependent upon clock accuracy. Normally we achieve that accuracy from NTP time servers while connected to the internet. Unfortunately with the X days off grid series, it would be ridiculous to use the internet (even if we had it) to synchronize my clock, considering the series is entirely about communications off grid. 😀

To circumvent the problem of not being connected to the internet, I’ve decided to use a u-blox GPS dongle.

Here’s my original blog post with instructions for setting up the GPS dongle as zn NMEA source to synchronize your clock. If you happen to be connected to the internet it will also use time servers from the net. If you’re out in the field away from internet access, it’ll simply use the NMEA from your USB GPS.

Setting up a USB GPS as a nmea Time server for your Raspberry Pi clock .

Portable Power for Raspberry Pi

Another popular topic is portable power for Raspberry Pi.

Here’s my blog post on building a 12v DC to USB cable adapter for the Raspberry Pi. It’s pretty simple, and requires just a few parts. This allows me to integrate the Raspberry Pi into my Portable Off-Grid Battery & Solar Power strategy for Amateur Field Communications:

Here’s the original blog post. https://oh8stn.org/blog/2018/09/27/portable-off-grid-power-for-the-raspberry-pi/

Finally, after the plethora of things I had to do for when link, updating my Raspberry Pi, setting up the GPS, access point,… There was still one thing I needed to do before I could pack up the station. That is actually making a clone of my SD card. This way if something happens out in the field, my SD card is corrupted or destroyed, I have a bootable backup to restore it to where it was after I’ve made all of these configuration changes.

NW Digital Radio DRAWS

NW Ditial Radio has just release a Hat for teh Raspberry Pi,. This is an epic change in digital communications for the Raspberry Pi power digital ham radio station. Please read my blog post on DRAWS here. https://oh8stn.org/blog/2018/11/18/digi-mode-ham-radio-hat-for-raspberry-pi/

Raspberry Pi for Ham Radio

X Days Off Grid

If you haven’t already seen the trailer for The X days off grid series they look.

Rock and roll guys

73
Julian oh8stn

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