- On this episode I'm back
and we're starting the build project
on the Raspberry Pi field computer.
This the the Field Radio Podcast.
(upbeat music)
Hello and welcome.
My name is John Jacobs W7DBO
Whiskey Seven Delta Bravo Oscar
if this is your first
time hearing the show
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Thank you for clicking and tuning in.
On this podcast, we cover and explore
operating amateur radio in the field.
You can find more information
about the Field Radio podcast
at fieldradiopodcast.org.
Over the past year I've
had the opportunity
to drop in as a guest on the
Ham Radio Workbench podcast
with George and Jeremy.
This has allowed me to keep my
podcasting membership active.
I figure with the new year
that I would restart this
podcast and move forward
with some exciting new topics and content.
I wanna thank those who reached out
with words of encouragement
to take back up
podcasting program.
2019 was an interesting year
that made putting the
podcast on hiatus for a bit.
I'm excited to get back to
regular podcast schedule
and this is where you come in.
The hardest part of running a program
is finding guests to come on
the show and tell their story
or share experiences.
You can only listen to me talk for long
before needing a second voice.
So I'm putting out the call for guests.
If you're interested in coming on the show
or coaxing a Ham buddy
to come on the show,
please reach out to me at
fieldradiopodcast all one word
at Gmail.com.
A goal for this year is
to build the ultimate
Raspberry Pi field computer.
I've been on and off
with the Raspberry Pi.
In my side business with CommsToGo,
I developed several
Raspberry Pi to go cases.
I have been mostly off
because of the complexity
of building and maintaining
the software side of the Pi.
Well, the past several years,
there's been great developments
in making the Raspberry Pi
a viable option for a field computer.
Two giants who have contributed
to moving the ball forward
is Julian Oscar Hotel
Eight Zero Tango November
with Survival Tech Nord
and Jason Kilo Mike
Four Alpha Charlie Kilo.
Julian has demonstrated
the viability of a Pi
in the rugged outdoors
and Jason has paved the way
with very simple set-up procedures
to remove some of the mysteries
surrounding software installation.
Also the emergence of
digital modes to communicate
in the field has worked
nicely into operating portable
with low transmission power
which is a great for
extended field operations.
So with this convergence of contributors
such as Jason and Julian,
teaching us and the digital
modes being more prevalent,
now is a good time to
take up this journey.
So a few episodes this
year will be surrounding
the build project
of several different
Raspberry Pi field computers.
Getting started in this project
after pulling a Pi off the shelf,
blowing off the dust and
loading up the basic software
was experimenting in the shack
on what the capabilities are
and how would this best
be deployed in the field.
One thing I like to do is go on Google,
hunt for Raspberry Pi
cases others have built,
watch their videos or look
at photos posted online
and take notes on what were
some good design elements
and some bad design elements.
It is great to see innovation in this area
and how I can incorporate
this into my project.
As I have mentioned before,
when looking at building a Go Box or Bag,
there are five main questions to ask.
Asking these questions upfront
helps you save time and money.
After going through this thought exercise
on several projects
and presenting at club
meetings and Hamfest,
I've added a question or two to the list.
So let's go over these five questions.
First, what is the goal?
It may seem obvious to ask this question
but many times it is
unfortunately overlooked.
We skip the first step in
putting something together
based on what others are doing
and forget to ask the question.
So for my build project, the
goal is forked several ways.
So which one will need to
be addressed individually?
Goal number one is to
operate weak signal modes:
FLDIGI and Winlink in the field.
Goal number two is to use
this computer to log contacts
in the field when using different
modes including the phone.
Goal number three is to use the computer
to work satellites
including Ham satellites,
weather satellites and the
International Space Station.
Goal number four is to
operate and experiment
with SDR applications that
can be used for many uses.
Now that I have identified
my goal for this box,
the second question is
what does success look like?
I've defined four parameters.
First, the rapid field deployment.
I want the system operational
with as little connecting
of components as possible.
The second item of success is
the ability to get on the air,
meet the defined goals of digital modes,
login contacts, working
satellites and SDR operations.
The third item of success
is the unit will be able to
maintain extended operations
such as a field day deployment.
The fourth item of success
is the Pi makes operating
in the field more enjoyable
and fun to operate.
I'm not interested in frustrating set-up
and operation in the field.
Now these four items may
sound like a familiar pattern.
That is because it follows
my four overarching goals
at field operations.
Get on the air, stay on the air,
be an effective communicator and have fun.
So now that we have identified the goals
and defining what success looks like,
next we look at defining what the box is
and more importantly, what it is not.
It is a field computer.
It is not a radio.
It does have a battery but
will not power a radio.
It can be charged via solar
however it will not have an
onboard solar charge controller.
It is going to be
lightweight computing option
and not a regular power hungry laptop.
Putting down what it is not
helps you keep your build
project from becoming
a shack in the box.
Lastly, the new item to look
at is under what circumstances
will the box be used?
Or how will the box be deployed?
This new item will help you in
your decision making process
because a field computer in
an emergency command center
is going to be vastly different
than a computer on a solo operation.
So for this box, it will
be used in the field
alongside my Icom 7200
and my Kenwood D-710GA.
These two are not lightweight items
so we are not counting grams on this one.
Also the Icom 7200 has
USB sound card built in
so the case does not need
something like that on board.
The Kenwood D-710GA does have a TNC
but will need a serial
port to pass that data
to the computer.
Also, my Kenwood box already
has a signal link on board
so check that off the list also.
Lastly for solar recharging,
I already have in a small case a LiFePO4
solar charged controller
and array of solar devices.
So the box just needs to
accept charging input.
So check solar off the list.
Okay so going through this process
is defining some parameters
for the build project.
From this point, it is
safe to gather your notes
from observations of others
that have gone before you
and start building a list of components
and rough layout to see what
size of box will be needed.
The goal of all field deployment equipment
is to be portable, organized, tested,
modular and understood.
As we work through the
design and build process,
these five items will
drive decisions being made
in the design to build
and in the spring when things warm up,
a bit of the testing of the project.
So here's some early conclusions
to start dealing the ball
rolling on the build out
version of Raspberry Pi.
The future proof, the project,
and to get the most out of the set-up,
I'm going to get the Raspberry Pi Four.
Wile I have some other three's around,
I'm using those for other lesser projects
such as 3D printing or my
future APRS weather station.
For reasonable redundancy,
I've decide to go with Dual
Raspberry Pis in the box.
They're small enough and cheap enough.
The two is one and one is none
can be reasonably accommodated.
So two Pis in the box.
This will also help in multitasking
such as logging and operating modes
or listening in on weather satellites
while doing other tasks.
Display interface.
For the display, I have done
some research in the area
and some experimenting on my own.
There is a popular opinion
to do what is called
a headless Pi.
Meaning instead of hooking up a monitor
directly to the HDMI output,
you can use software and
WiFi to broadcast the signal
to a tablet.
There are some great
advantages to using this option
but a few downsides.
Advantages that you do
not have to be tethered
to your gear.
However, the downside is,
that if there is any
issue in this process,
you have no way to
diagnose what is happening.
I had a Pi that would just blink
and never connect over SSH
to even get the command line.
Had I not had a monitor,
mouse and keyboard,
I would not been able to
look at the boot screen,
see what the issue is and fix it.
Furthermore, having a
tablet is one more device
to keep charged and keep running.
So while the headless Pi
would be a nice addition,
it will not be the primary
source of connecting
to the Pis interface.
And one last item from the
other build observation.
The screen needs to be a usable size.
My eyes are not the best
and these little four-inch monitors
are not going to fit the bill.
For me at least, I will need
a substantial size monitor.
Keyboard and mouse.
For the keyboard-mouse interface,
I have also found that
using the headless option
takes some getting used to
and having to drag and drop
the mouse around the screen,
opening and closing the virtual keyboard,
lastly the lag in response.
These things at least so far
have been a bit frustrating.
Taking me back to this being
a fun device in the field
and not something complex and frustrating.
So I do need some type
of mouse and keyboard.
Perhaps a touchpad so
a desk is not required.
Battery and power.
The Pi runs five volt and we like 12 volt.
So we'll need some power
conversion in the box
to make this happen.
An energy efficient field monitor
should also be some form of DC
that may need some conversion
Overall, you're really
sipping, not guzzling amps
with the Pi.
So a large source is not needed.
A six amp hour LiFePO4 battery
from our friends at Bioenno
power should work quite well.
I was given external port in all my boxes
to drive power from an external source
such as another battery or a power supply.
But the battery should last on its own
for quite a long time.
Field testing will bear this out on
is what to be expected on processing power
and monitor amp drop.
Also having the external
solar charge controller
will allow me to throw out some panels
to fill backup the battery or the case.
Looking at the case, I know I
will have a good size monitor.
I like seeing some of the briefcase build
where the monitor is in the lid.
I know the case does
not need to be too big
knowing that the basic components
would be a battery, monitor and two Pis.
The rest are components to support it.
So a nice small Pelican
or Harbor freight case
should do the trick.
A fliptop lid dry box
would be over the top
for this build.
In all my builds, I have freely
drilled holes in the case
to mount plates and batteries.
I have no issue with drilling holes
however on this build,
I would like to have
a free floating system
to access the components
behind the face plate easily.
So this box there may be fewer
screws penetrating the box.
Required components.
Knowing I'm going to be doing
weak signal digital mode
such as FT8 and GSA Call,
I know from Julian that we
need to have good, precise
clock time on the Pi.
To make the Pi affordable initially
and to fill the purpose of teaching code,
the clock on the board was sacrificed
but a simple chip with the battery
puts the clock back on board.
Adding the GPS receiver lets
the clock update in real time
over GPS and give GPS positioning
for APRS and other items.
To interface with my Kenwood,
I would love to go native serial
and not have to deal with
the USB to serial adapter.
So I want the Pi to
have a serial interface.
Lastly, having some room in the box
for an SDR receiver,
filters, amps et cetera
would be nice to have already connected
and not an add-on accessory.
Dual Pi components.
With the Dual Pi set-up,
I do not want to have to build something
with two monitors, two
keyboards, two touchpads.
So adding a USB switch
will allow me to switch
a single keyboard and
trackpad across both devices.
Also an HDMI switch will
allow me to change inputs
on the monitor as needed
between the two Pis.
Possibly I might look at adding ports
to allow for an additional
external monitor to be connected
for items like field day
where a second monitor
is helpful for logging.
Optional components.
With every project, I
like to throw in some
additional components and connectivity.
A few USB ports for charging a phone
or putting the USB light
are always welcome.
Perhaps if room some PowerPole
out to run some additional
external components like
an external monitor.
This like all my recent builds
will heavily depend on 3D
printing for the plate design
and mounting brackets.
This allows me precision
in placement of components
and ability to keep everything
inside the closed box.
I do not mind the occasional
drill hole in the side
for a nut and screw placement.
However, I continue to
see the use of ports
on the outside of boxes for
antennae, power and switches.
After my first few builds years ago,
I saw the dirt build up
on these external items.
I moved to put in everything
on the inside of the box
where the dirt and
moisture cannot wreck havoc
on the long-term
sustainability of the gear.
So next steps.
Source the gear and start to
do some CAD drawing layouts
of the components
and see what will fit and where.
But having defined the project scope,
we now have sound footing
to start building the box.
Now I'm sure I've already made
some missteps in decisions
and many more sure to come.
But I hope through going
through this thought exercise,
these can be minimized.
Defense Secretary Donald
Rumsfield was quoted as saying
"We know there are knowns;
"there are things we know we know.
"We also know there are known unknowns;
"that is to say we know
there are some things
"we do not know.
"But there are also unknown unknowns,
"the ones we don't know we don't know.
"The unknown unknowns
are the hardest ones."
So I'm sure there are some
things that I don't even know
that I don't even know about
and that is the fun part of this process.
One last item that I
have picked on this idea
of using a Raspberry Pi in the field.
There are many items that require
command line instructions.
There are points where
you need to break away
from the mouse click and type code.
I see this not as a
negative but a positive.
It is fun to get your hands
a bit dirty in computer code
to build a stronger, more
stable system than you would get
with the traditional PC.
So there are some learning
curve to this process
but that is also part of the journey
and part of the fun.
I hope you join me on this
process over this next year
and perhaps work on your own project
as we move down this road
and gleam some insight.
I hope you can share with me on Facebook
or via email some ideas
to help me on our way.
That will do it for this episode.
I hope you join me next time where we
take this build project
one step down the road.
Thank you to those on Patreon
for continuing to support the
podcast in YouTube channel.
Thank you to those who watch my videos
or click on the affiliate
links to help fund this channel
and thank you to those
who share this content.
You too are supporting this channel.
Show notes and additional
content can be found
at fieldradiopodcast.org.
As always, please send me
your comments, feedback
and show ideas to
fieldradiopodcast@gmail.com.
73.
(upbeat music)
