Folding Solar Panel

I own a 120W solar panel which is great for recharging my batteries when I'm camping and doing outdoor radio activities. The problem with it is that it's too big. I cannot get it into my car easily. So the obvious thing would be to get a smaller panel. OK, but smaller means less power and oddly, they are more expensive than larger ones when converted to "$$ per Watt".

The obvious solution was to buy a folding solar panel. It would deliver the power I want and also fit into the car. However, have you looked at the price of folding panels? They run about 3 times the price of a non-folding one at the same power output. No thanks.

So what to do? How about I build my own!

So that's what I did. I was able to source some 40W panels from Amazon for $55 each including shipping. A continuous or "piano" hinge, a pair of sash window locks and a handle were all that was needed to complete this project.

Here we see the back side of the panels. I used the hinge as a template to drill holes for the rivets I used to secure the hinge to the panel. Once the hinge was installed it was on to the wiring. The panels had a nice box on the back where the connections were made. Opening the box revealed 2 screw terminals. It was a simple job to add a pair of ring terminals to one of the wires and connect it to the other panel's junction box.

So what was the point of making this? Look at the picture below. This is me and my telescope equipment. I took my family to see the Great American Solar Eclipse (August 21st 2017). Powering their devices and all of my telescope gear, laptops etc took quite a bit of power. I was able to do this by using a large deep cycle marine battery and this solar panel (and the relevant charge controllers etc). Look closely just below the bottom left corner of the black box housing the laptop. You can see the panel on the ground.

Solar powered GMRS repeater

I recently made a solar powered GMRS repeater for use on a remote farm. The largest building on the property is the barn and so this was chosen as the home for the machine.

So this is the almost finished repeater mounted onto the wall of the barn. There are still a few jobs to complete such as running the antenna coax and mounting the solar panel outside. We ran out of time before the summer storms came and we had to go home. Luckily we'll be back there shortly so can finish it up.

It's a simple setup consisting of 2 UHF Motorola SM50's, a "mobile" cavity filter, Raspberry Pi 3 running SVXLink repeater software, solar charge controller, 35 Amp lawn mower battery and various wires and connectors. Oh, and a solar panel and antenna. Total cost for this machine was about $325.

ACME fails again ...

Here in the DE/MD/NJ/NY/PA area of the US we have a supermarket chain called ACME. I swear to Bob that it is run by idiots!

I spotted this in my local store recently.

It's a recall notice. It tells of a product recall for a chicken nugget food item. But look behind it on the shelf (click the pic to enlarge). It's the very same item that has been recalled!!!!

3D printed Anderson Powerpole distribution box

I have a Robo3D 3D printer which I'm having a lot of fun with. I'm also trying to build a GMRS repeater for use on a farm. I laid out all the hardware only to discover that I needed a tidy way to distribute the power to the various devices.

The repeater being laid out on a 2'x2' piece of 3/4 plywood

Meet the Parametric PowerPole Breakout Box which can be found here on Thingiverse. The Parametric part comes from the way in which you can create anything from a 2 port to an 8 port box.

I printed a 4 port box. As you can see, it has 6 ports. No my printer did not do it wrong. The ports at either end allow the power to be connected to the box without loosing one of the 4 ports. One can also stack the box together to make larger boxes. In the above pictures I've assembled the connectors the wrong way - DOH. Luckily I caught it before I soldered it all together.

That is #12 solid electric wire connecting the PowerPoles together. I pulled the ground wire from a small run of Romex household electrical wire and used it to connect things together. The joins were wrapped and soldered and the ends were crimped and soldered.

Depending where you get them from PowerPoles can be as much as $2 a pair so using that price as a guide (I buy mine in bulk and have them on hand) I managed to construct this box for about $15 including the price of the PLA 3D printer material, electricity etc. Not too shabby!!

Schrodinger's Cats?

What is it about cats and boxes. Every time you put an empty box down onto the floor it becomes immediately inhabited by a cat. Or does it? 😉 Perhaps this was what captured Schrodinger's imagination and shaped his ideas on Quantum Physics?

For the cat lovers out there, here is a collection of just a few of the cats that inhabit my apartment. Please understand that they are not _my_ cats. Indeed, one of the cats has another cat as his pet.

Elvis

Gracie

Boots AKA Orange Dog

Gracie

For his next trick, Boots will make a girl disappear

Rascal. He's a Lhasa Apso with a Doberman complex. The cats are bigger than him.

Wash my clothes in what?

Found at the local Korean supermarket

My girlfriend asked if they had any Dragon dung but this was the closest they had.

Programming the Motorola SM50 under Linux

The Motorola SM50 and SM120 are quite a common radio and pop up on eBay all the time for modest prices. As with all Moto gear they come in a variety of models; wideband, narrowband, 2 channel, 16 channel, 40 watt, 4 watt etc etc etc. There are various model decoders available around Al Gore's Interweb Tubes so we won't be covering that here.

I am the proud owner of quite a pile of SM120 M44DGC20C2AA (40W UHF high wideband) models which are ideal for a repeater blabber box, GMRS or FirstResponder use such as your local Ambulance Squad.

Programming them back in the early 90's (yep, they are even older than that!) was by way of a DOS program running on a lowly i286 PC. But hold on, we are on Linux. How's that gonna work? Take a quick look at this youtube video ...

Things you'll need:

A Linux box (DUH!)
DosBox emulator software (apt-get install dosbox)
SM50 programming software (can't help you there but it's not hard to find)
Motorola GM300 style programming cable or "RIB" (I use a USB one from ebay)

How to do it:

Using your favourite terminal program (I use Yakuake) fire up the dosbox emulator by typing 'dosbox'. If you have a Z: prompt then that part works.

Unpack your SM50 software into a folder. Navigate to that folder and then fire up your favourite text editor. we'll be making a config file called 'sm50dosbox.conf'. Mine looks like this ...

[cpu]
core=auto
cputype=auto
cycles=191
cycleup=10
cycledown=20
[serial]
serial1=directserial realport:ttyUSB0
serial2=dummy
serial3=disabled
serial4=disabled
[dos]
xms=true
ems=true
umb=true
keyboardlayout=auto
[autoexec]
# Lines in this section will be run at startup.
# You can put your MOUNT lines here.
mount C /home/g7ltt/raid/Filestore/DOS
mount M /home/g7ltt/raid/Filestore/motocd/SM50/R030000
m:
m:\SM50.EXE

Adjust the 'serial' lines to match your USB port. Also adjust the 'mount' lines to reflect your path. In my case 'C' becomes C: and holds a few DOS utilities. The 'M' becomes M: which contains my SM50 software. 

Save your file and the type 'dosbox -conf sm50dosbox.conf' and watch it all fire up. You'll have to configure the dos software to use COM1 but otherwise you'll be programming in no time.

In theory this should work for other Motorola DOS based programming tools for other radio's. However, I've not been able to get the GM300 or Maxtrac software to communicate with the radio. It seems that (for USB cables at least) the serial speed of 930bps is not supported by either the OS or the emulator.

If you get one of the other DOS programs to work please do drop me a line.