A Quick and Easy Tablet for Field Radio Use
Setting up a cheap tablet for use in the field.
Whether you are a new Technician-class license holder looking to develop VHF/UHF digital capability or an experienced field operator looking to lighten your load for those field exercises, setting up a cheap field radio tablet is a good weekend project for you.
A couple of years ago, I was inspired by a post by NCScout to set up a tablet for field use. His concept was pretty focused on clandestine communications, but served as a basis for my own concept. What I wanted was a tablet set up to be generally useful in the field, not just for radio, but with a definite focus towards developing VHF/UHF digital capabilities. I wanted something with GPS, a lack of a cellular modem, and at a price point that wouldn’t break the bank. In addition to digital radio communications, I planned to use this tablet for offline mapping, imagery, and drone control.
The device I chose was a simple, cheap Onn 8 Pro tablet that I picked up for $50 from my local big box store (price as of 2020). I’m sure there are a multitude of better options out there now, but the features were a good value for the price. The model charges via USB-C, includes a headphone/mic jack, a microSD slot for additional storage, and front and rear cameras. I dropped a rugged case for it into my Amazon shopping cart and got to work on the tablet itself. For starters, if you’re technically savvy a good option is to Root the tablet. Rooting removes all traces of Google from an Android device, but there are unique processes to do so for each device so you’ll have to research this on your own. If you’re not able to Root the tablet, be mindful of the fact that there are several Google apps on the device capturing your data to sell to third parties. If possible, disable all of the Google applications you can on your tablet before proceeding, including the Play Store. A good replacement for the Play Store is F-Droid. Once I got that installed, I began using it to install apps onto the tablet, whenever possible. If there are any apps you want to install that are not included on F-Droid, such as AndFlmsg, just search for them followed by the phrase “APK” to find the necessary installation files. Do your own research on sites to download APK files. I prefer to use APKPure.com as my source if I cannot find a direct download from the app’s publisher. As far as apps go, I keep my tablet fairly minimal.
My radio apps consist of AndFlmsg, RadioMSG, Rattlegram, and APRSdroid. When it comes to tablet-based digital radio comms, AndFlmsg is your Swiss Army Knife. An Android-friendly version of FLDIGI, it includes support for standard ICS forms, along with custom forms such as those I provide here. The user interface isn’t intuitive for those of us used to using FLDIGI in full powered computers, so I’d recommend gaining some familiarity with it before heading out to the field. When adding custom forms, make sure to add the custom forms to both the DisplayForms and EntryForms folders in your NBEMS.files directory.
Radiomsg is a radio application developed by the same guy who programmed AndFlmsg, and provides a simple method to send text, photos, and positional data to an individual or groups over UHF, VHF, or HF.
Rattlegram is a relatively new app that allows for simple text messaging over radio, but without requiring the use of any sort of cabling between the tablet and radio. This process is called audio coupling, and the primary benefit (not needing a cable for the radio) also results in some drawbacks. You may not always want your audio broadcasting in the open (such as when hunting), and in noisy environments the radio may not pick up the message well enough to transmit it clearly.
APRS has some real utility, though I prefer to use it in special cases. I’m not a huge fan of broadcasting my location everywhere I go, but Jason (KM4ACK) has a couple of interesting videos on how to receive weather forecasts in the field using the WXBOT service. In addition, the SMS and email APRS functions are nice to have when operating outside of cell tower coverage, and APRSDroid provides a mapping capability of packets received that can be quite useful.
Using these radio programs paired with a Baofeng APRS cable allows for quick and easy digital communications with any HT that comes with a Kenwood-style microphone jack and has a VOX mode. You could also pair up a Mobilinkd TNC or a sound card interface of your choice.
My primary offline mapping is done via OsmAnd. In addition to OsmAnd, I also installed a program called OruxMaps. This is a neat program that lets me create my own maps and store them for offline use. What is nice about that is I can create a map of my area and add the names of the owners of the neighboring land, or annotate various points of interest. Additionally, I found an app called Image Markup that allows me to add notes and markers to photos on my tablet. I have found this particularly useful for making ad hoc range cards when bow hunting from a new stand, but the program has any number of interesting uses.
I then installed an app that allows me to control my drone from the tablet. Finally, I installed Paranoia File and Text Encryption tools, as well as Wire and Signal for online communications, and Anydesk so I can remote into the various Raspberry Pis and other computers used in the shack at home.
Quick and simple. If you’re looking for an easy way to set up field VHF/UHF digital communications, a cheap tablet is a good way to go. When you pair it with the potential special use utility of APRS, offline mapping, and a few other simple apps, it becomes a pretty valuable addition to your field kit.
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A big plus for the Android-based tablets is battery life. Also, at their low price point you're less likely to cry when you drop it out of a tree. It would be nice if more of them were capable of running GrapheneOS than the Pixel Tablet though. The Surface tablets are nice if you want the ability to run a full Linux system, but the more affordable ones (like the Go2) suffer from not-so-good battery life - and you'd still pay more than $50.
I don't see this tablet other than used available anymore. Any other suggestions? I have a couple cheap chinese tablets that send but won't receive. Work fine without the btech aprs cable. Trying to use andFLmsg app with an ht.