Building a Portable Digital HF station for use in various activations I have planned for summer/fall 2021. Hope to have the DRAWS/RADIO set up and running before this summer. I am NOT going to drag a FlexRadio Flex-6000 to some of the places I hope to operate from.
On the digital side I am using a Raspberry Pi (4B) with a specialized add-on bit of hardware, the North West Digital Radio DRAWS that will add a GPS/on-board clock and the necessary interfaces.
Initial intention is to us a SGC-2020 transceiver, but I may drag a TenTec Jupiter to my activations instead. I will use a keyboard and mouse to control the actual digital software for the activations, WSJT or perhaps fldigi.
The DRAWS is a neat bit of kit that should streamline my station and reduce the component count. That said it is as best semi-documented and a bit of a work in process intended for those willing to roll their sleeves up to get it configured, wired and going. Not very plug-n-play at all.
Some courtesy definitions:
DRAWS = Digital Radio Amateur WorkStation developed by North West Digital Radio http://nwdigitalradio.com/draws/
Raspberry Pi = the series of small single-board computers developed in the UK by the Raspberry Pi Foundation along with Broadcom. https://www.raspberrypi.org
Raspberry Pi HAT = Raspberry Pi extension board, both because it sits like a “hat” on top of the Raspberry Pi microcomputer and as the original meaning apparently was “Hardware Attached on Top” https://github.com/raspberrypi/hats/blob/master/README.md
A bit about the DRAWS lifted from the NWDR website:
DRAWS is a platform with multiple components.
First, it is a Raspberry Pi HAT. This is a purely hardware solution that puts several components that are useful for amateur radio projects on a single board; namely a high-performance sound chip (CODEC), a GPS with pulse per second (PPS) that includes an embedded battery backed real-time clock (RTC), and a 12VDC power circuit to power the onboard devices and the Raspberry Pi from a single power supply. It has two mini DIN-6 audio sockets that match the ‘TNC’ specification found on many radios designed for amateur radio, an SMA connector for a powered GPS LNA antenna, power connection socket, and a small GPIO array for additional I/O.
Secondly, the DRAWS Workstation, which is the HAT plus an SD Card, Raspberry Pi, and an optional metal case, which creates a self-contained unit. The Raspberry Pi provides the computing power for the workstation to run the drivers for the HAT components and applications to provide various functions. Those functions are mostly in the realm of packet radio (Direwolf modem, AX.25, APRS, etc.), other digital modes (fldigi, WSJT-X, etc.), and digital voice (D-STAR, etc.), and ancillary utilities and applications such as a Stratum 1 timeserver, GPS location, and so forth.
NOTE some of the devices on the DRAWS HAT run on 12vdc. So you will need to fabricate a cable using the provided pigtail to either use the 12vdc your radio uses, or a separate 12vdc power supply. Since you can configure things without the 12vdc I deferred the cable making for another day.
BATTERY NOTE – the DRAWS HAT takes a CR1220 3v lithium coin-cell battery. You can run it without, but if you want your DRAWS to keep time when not using the internet or the GPS – unless you plan to leave it powered on all the time – the onboard clock will lose time sync without the battery.
SD Card Note – get an extra 16GB (or bigger) SD Card to build your system on, that you can dedicate to this build.
You need a Raspberry Pi 3 or 4, the DRAWS unit itself, and all the cables.
PLEASE NOTE – most of the NW Digital Pictures show an EARLY version of the DRAWS, where the GPS antenna connector comes out the side of the HAT where the DIN connector cables are. If yours looks like the picture, you have an EARLY ADOPTER version, if the SMA GPS comes out the end where the white 12v DC outlet and the black accessory outlets are, then your have the LATER version of the DRAWS.
Electrically they are are the same, but if you want to buy one of NW Digital’s neat aluminum enclosures you need to know which type of DRAWS you have. I made the mistake of presuming NW Digital would show the actual version of the product they are selling, but that wasn’t the case in March 2021. [Edit 29MAR21 – NWDR does have pictures, buried deep in a blog post titled “DRAWS Cases Have Shipped” – http://nwdigitalradio.com/draws-cases-have-shipped/ which confirms that NWDR is showing the EARLY version rather than the PRODUCTION version everywhere else. Would have been nice if they would have linked the blog post to the product descriptions in the online store area.]
If you order a DRAWS now you won’t have my mismatch problem. Actually I shouldn’t have the problem either, as my DRAWS shipped a few weeks after the so called cut-off, but such is life.
[Edit 29MAR21 – the more I dig into the various information channels NWDR uses (found their Wiki, Website, Blog, Repository, and Groups.io so far) more information is out there, but is neither all in one place nor cross-referenced/linked. Curation also is in short supply, as obsolete information is left in place without an notes indicating that there is newer information available. Suggestion for NWDR would be make one single reference primary (would have to be their website as that is where people start) to either contain or offer the latest links to all the DRAWS information. As it is the project wouldn’t past muster to be included at someplace like Instructables or Make Magazine because of the scatter locations and loose ends.]
First step – from the Wiki print the “Getting Started” guide. You can do from online, but I used my copy to make notes and check off the steps as completed.
Head’s up – the Getting Started Guide skips some steps that could bring you to a halt pretty early on.
Also you need to be comfortable enough to follow directions using a Terminal Console window. If that isn’t your scene see if you can line up some help before you come to a grinding halt.
Now you create the SD card that your system will boot from, so downlead the latest image and directly create your DRAWS SD card, but ignore the Getting Started Guide by using the Raspberry Pi Imager app from RaspberryPi.org Makes quick work of the job, including verifying the card.
Next you have to use an ethernet cable to connect the project Pi to the internet to do updates. While you might be able to command line enable your Pi’s wireless, the directions ask you to not configure the stuff that the wizard usually does until you have done several DRAWS specific steps.
Your DRAWS HAT may have a different card number the First Boot section – mine is card 2
Updating the NWDR image configuration scripts wasn’t possible because of certificate problems blah blah blah… so I skipped that stage as I had downloaded the supposedly absolutely latest version with the image moments before.
Some of the Raspberry Pi OS updates/upgrades had dating issues
You can type reboot to force the reboot.
Second Boot is important as it puts your callsign in the right places, gives you options to diddle some AX.25 things and toward the very end of the scripts helps you rename your Pi to something like DRAWS-Callsign.
Third boot you are supposed to configure radio specifics for your particular radio. As it says that the default is what you want if you intend to run an HF app (I plan to run WSJT-X or WSJT-Z) I breezed through this part hoping I left it in default mode.
Everything in 4 is about packet, AX.25 and a section on restoring to default to change back to plain old HF program usage. There is an option to turn off the on board DRAWS HAT sound if you wanted to. And a section of making your own image, but since you already did that at the start I neither did that step nor figured out why it is even there.
Now you verify that your have your DRAWS configured. Unless you are doing packet you skip the test of direwolf and UDRC.
I stopped at this point with everything except as noted successful.
Next session I need to have a radio ready, have an internal battery for the clock, make up the 12v cable for the HAT and have things ready to actually run.
I ordered the correct enclosure for my Early Adopter DRAWS HAT right when I found the issue, so I can build up a nice package for the portable uses I am planning for this summer. When I get my setup running, I will order a new DRAWS which can go into the first case I bought. I often build a duplicate setup for backup.