Looking For A Air Gapped Tablet

[johnymac]

Okay folks, I am having a heck of a time finding what I am looking for and thought I would reach out to the pi forum for advise.

I am an amateur radio operator and am putting together a new field comms kit. The kit will have a small footprint and weigh less than the 6-pounds I am lugging around currently. I have the transceiver, and modem but the computer part is missing. The computer or tablet would run digital radio programs like FLdigi.

I tried a Lenovo M8 tablet but found out it will only work if you down load software from the internet. I want a tablet or small computer that will never touch the internet. I will download software via a card or memory stick direct from the manufacturer.

Does Raspberry pi carry a light weight (under 1.5 lbs) option that is air gapped and will take software from another source other than down loading it from the interwize?

Thank you,

73 & God Bless,
JohnyMac KC1FWU

[aBUGSworstnightmare]

Where do you want to get that SW from? Another PC or ...?

Looking for a tablet like RPI -> https://cutiepi.io

[RGJ-PI]

CutiePi would do the job nicely but be aware that the Compute Module 4 fitted as standard is one with WiFi and Bluetooth onboard. You could swap out the fitted one for a non wireless CM4 though.

[B.Goode]

The computer or tablet would run digital radio programs like FLdigi.

To avoid frustration/disappointment I suggest that before parting with any $$ you should check with the developers of FLdigi that it can be installed and run on your selected computer hardware. I would not be confident that FLdigi will work with Raspberry Pi boards.

Does Raspberry pi carry a light weight (under 1.5 lbs) option

Nothing in the current range of Raspberry Pi hardware approaches that weight. https://www.raspberrypi.com/products/ (But equally nothing there could be described as a tablet.)


Raspberry Pi rely heavily on the global Internet for distribution and maintenance of their Operating Systems and other tools. You might be able to get a functional OS on a microSD card from a reliable retailer.

[Undertow]

When you say "air-gapped" are you using it in the traditional "must be secured from the outside world" sense or just mean you won't have an internet connection? Also what do you mean by Lenovo will only work if you download software from the Internet? While that's the common method you can generally install and update user software on Android tablets without an internet connection. Maybe you have some specific need though otherwise? Is it permissable for the device to connect to the Internet if you explicitly allow it for initial setup or to update or do you really need to be 100% certain that bluetooth or wifi (or maybe even physical ethernet) can't be enabled by a rogue app or accident?

A quick google finds reports of people successfully using fldigi on Raspberry Pi and Android.

[johnymac]

@ bugsworstnightmare. The plan was to down load to a memory drive and have the memory drive scanned for issues. Do you have a different suggestion on this part? Cutiepi, I will check it out.

@ RGJ- Pi, Cutiepi. Thank you. I am currently working, slowly mind you, to only having one computer that has access to the net. I was up one night late, and I saw my computer doing weird things. I contacted Lenovo, and they told me that that is normal as Lenovo does a scan of my computer to gather information on how they could better serve me. I found that feature and turned it off. I noticed Microsoft doing the same and I found a way of turning that function off too.

@ Undertow, I contacted Lenovo to ask how I could download an app using a memory stick or sd card. The agent told me it was not possible. "You must download via the internet". I explained to the agent that I did not want my computer touched by the internet. She went into a long dissertation "explaining" to me that in order to better serve Lenovo customers, all information on my M8 laptop is available to Lenovo for review.

@ BGoode, I did. FLdigi sent me a list and Rpi was on the list. As a matter of fact, they understood what I was trying to do and felt that Rpi was my best solution.

Thank you all for the help. I appreciate it.

73 Brothers & Sisters.

[aBUGSworstnightmare]

You can still root your tablet ...

[johnymac]

@ abugsworstnightware wrote, "You can still root your tablet ..." After chatting with the agent at Lenovo, I sent the tablet back.

The Cutiepi looks interesting. I can not find anywhere the weight of the tablet. Do you or someone else know? Thx

[Undertow]

@ Undertow, I contacted Lenovo to ask how I could download an app using a memory stick or sd card. The agent told me it was not possible. "You must download via the internet". I explained to the agent that I did not want my computer touched by the internet. She went into a long dissertation "explaining" to me that in order to better serve Lenovo customers, all information on my M8 laptop is available to Lenovo for review.

Lenovo rep was misleading. The exact method (known as side-loading) varies with recent Android but you either globally enable allow install from "unknown sources" (that is not Lenovo or Google) or give individual apps permission to do so at your request. Once appropriate permission is set you can then just directly install or update the apk (Android package format) from sd card or usb connected device. There's also the possibility to use adb to transfer and install the apk from another computer.

I also see the LineageOS Open Source build of Android seems to be available for Lenovo M8 which would allow you to completely get rid of Lenovo and Google from the setup but that's really out of scope for this forum. Edit. I see you sent it back so forget that

[Gavinmc42]

Works on Pi's
https://sourceforge.net/p/fldigi/wiki/debian_howto/

Pi400 with a tiny Cyber Deck LCD?
https://www.adafruit.com/product/4863

You could use any of the other Portable HDMI monitors.
Waveshare HDMI LCDs go down to 2.8"

On Pi's you just turn WiFi/BT off.

External battery pack made from a Cordless drill battery.
But HAM's have big 13.8V power supplies ?

Anyone make a Pi400 docking station with dual displays and battery?

A CM4 without wireless would be fun if there was a display mother board.
Hmm, there is an off the shelf Pi Terminal, in a nice case, bit more expensive.
CutePi is a bit bigger.

A Pi with small 3.5" display hat and case, most have touch screen and GoodTFT works pretty good now.
https://github.com/goodtft/LCD-show

[ame]

@ Undertow, I contacted Lenovo to ask how I could download an app using a memory stick or sd card. The agent told me it was not possible. "You must download via the internet". I explained to the agent that I did not want my computer touched by the internet. She went into a long dissertation "explaining" to me that in order to better serve Lenovo customers, all information on my M8 laptop is available to Lenovo for review.

I think your tinfoil hat may be leaking. Did you know that you are being touched by the internet right now?

Raspberry Pi do not make a device quite like what you are looking for, but they do make the parts. For example they have a touchscreen that is compatible with the Pi, so if you have the skills you can build a "tablet" or "laptop" based on that. Lots of examples on the internet (ironically) that you could draw inspiration from.

[johnymac]

@ ame, thank you for your comments. Yes, I am aware I am using the internet right now. The internet is great for many purposes. With digital comms, internet is not needed. So, why do I want it if I do not need it. Download the software and move on. Thank you for your time.

@ Gavinmc42, some great info, thank you. Thank you for taking the time to share links too. You Rock!

The goal for my field comms is a smaller footprint and less weight than my my current field pack which weighs around 7-lbs - With my Lenovo ThinkPad included.

My existing field pack.........................................My new field pack
Yaesu 817nd transceiver......................................Xiegu G90 transceiver. (this radio has a internal tuner 'ATU')
LDG Tuner.............................................................Digirig modem
Signalink modem.................................................Par Endfed Quad antenna
Par Endfed Quad antenna...................................Wires for connections
Wires for connections.........................................12V 9 Ah LiFeP04 battery
12V 9 Ah LiFeP04 battery................................... ? Under 16 oz air gapped computer to run digital comms ?
Lenovo ThinkBook

The plan once winter passes is to increase by range via my two legs. Back packing into more remote area's for SOTA (Summits on the air) QSO's (contacts). For you backpackers out there, you know that every ounce you save is crucial. My goal is to have weight come in under 5-lbs.

Hopefully, that better explains what I am shooting for.

73
JohnyMac

[AndrewPiEater]

I have a Xiegu G90, it weighs 3 pounds on its own. The built in ATU is doggo. The 9Ah battery is 2 pounds.

[johnymac]

Thank you AndrewPiEater,

My G90 weighs a hair over 2-lbs and the battery I have weighs ~1.5-lbs. My Lenovo ThinkBook weights in at 2.75-lbs. The LSD tuner weights 13-onces. The Yaesu 817nd weights in at 2.5-lbs. If I '86' the tuner and find a laptop or tablet for around 1-lb, and go exclusively with the G90, I have eliminated 41.5-ounces or ~2.6-lbs.

I cannot speak to your experience with the ATU function on the G9., My experience coupled with the Par quad endfed antenna; the G90 works great. If you are having issues with the G90 tuning well with the internal ATU, I suggest you checkout the resonance of your antenna. You can do this with an antenna analyzer. You probably know all that, just pointing it out to the folks following this thread.

Thank you for checking in on my search for a light weight, air gapped laptop or tablet.

[AndrewPiEater]

The website claims 2.2 pounds, but I've just put the G90 on the scales. 1.6kg, without the microphone.

The built in ATU is OK on a basic diploe but will not tune my end fed, my MFJ easily does . A a stepped bank of tuners switched in by relays is never going to replace a mechanical cap.

[Gavinmc42]

The plan once winter passes is to increase by range via my two legs

I used to use these things called skis, most people don't know but Australia can have more snow than Switzerland.
That it is snowing now in summer where I used to live/ski is weird.
I did climb our biggest mountain Kosciusko with skis, but back then I was insanely fit and it is tiny.
Also still has snow/ice on New Years, busy place even then.

Understand now the weight issues, carried the radio more than a few times when I served a very long time ago.

I used to work behind a Uni firewall, no internet access for Pi's.
Manually installing C dependency files was pure pain, rarely worked well
I ended up using Ultibo, once installed there are no dependencies.
"Write once, Compile anywhere" almost true, even for baremetal applications

I have used these to power mobile Pi4's, they are common so find your "local" supplier, Adafruit, Digikey?
https://core-electronics.com.au/dc-dc-a ... a-75w.html
Hint, inductor can short to smd parts under it, so hotglue or silicone it.

Many decades ago I got a bunch of HMI devices , trackballs of every size and weird keyboards including a few cheap versions of this.
https://www.bhphotovideo.com/c/product/ ... board.html

I intended to use it for wrist mounted keyboard.
Never got around to using it, but I did find one the other day, I put it aside to try on the Pi.
Now I need to find it again
Save half the keyboard weight,

DIY keyboards and Trackballs are now easy to make, with plenty of yt vids and github code.
Pico runs the Ardunio HID keyboard code just fine, QMK too.
Keyboard on one wrist, display on the other?
Chorded keyboard, on my to do list
https://en.wikipedia.org/wiki/Chorded_keyboard.

Onscreen keyboard?
This one is a little big but has the cables out the side, makes it easier to go up the arm.
https://core-electronics.com.au/hdmi-5- ... creen.html
Add a case with flip up cover/sunshield.
I prefer mechanical keys

No compromise on display width resolution and cables out the side, comes in case too.
https://www.waveshare.com/product/raspb ... onitor.htm
You would only need some velco arm straps.

Wow has speakers too, I want.
Been working on my own projects now, this would be great for one of them.
https://github.com/BabbageBrassWorks/scenicus
Now I have to check the rest of the Waveshare range.

[johnymac]

Wow! Thank you Gavinmc42 some great stuff for sure.

Funny story, I just tried to fire up my new Xiegu G90 transceiver. Well it will not fire up. I monetarily push the power key and lights come on for about 1-second and then it shuts down. Hold the on/off switch and it fires up as it should but, once I release the power key, it shuts right back down. LOL.

I checked polarity, fuses, etc. and all are correct oh well.

Dropped the vendor an email and since it is Sunday, I am sure they will get back to me tomorrow.

"The best laid plans of mice and men..." I love Robert Burns

Thanks again and 73 Brother

[g4bch]

Loot ak the sBitx on https://groups.io/g/BITX20/wiki/2316 , not exactly what you are looking for but it uses a RPi and may give you some ideas