DIY

How To Repair A Broken Solar Panel

Having had solar panels on the roof of my home for the past several years has proven to be a worthwhile endeavor. With my particular installation I went with Enphase microinverters which I am pleased with. One of the things I like is the Enphase app on your phone. This allows you to look at the performance of each solar panel on your solar photovoltaic system. By the way, if you are interested in the details of my solar panel installation, click here.

A while back I noticed one solar panel was not performing as well as the others. Interestingly, it was putting out about two thirds the daily wattage of the other panels. So my first question was there a problem in the Enphase microinverter or in the solar panel itself. So I swapped solar panels between the defective one and a good solar panel. Doing a solar panel swap showed me that the problem was in fact with the solar panel.

In doing some internet searches as to why I had reduced output, I learned that solar panels have bypass diodes and that if one fails, it will cause reduced output on a solar panel. I also learned that in a typical 60 cell solar panel there are three bypass diodes which are located in the solar panel’s junction box. Below is a diagram of a typical solar panel:

The purpose of bypass diodes in solar panels is to protect solar panels from overheating when partial shading occurs. When partial shading happens on let’s say one of the three strings in the panel above, the output in that string drops to zero volts. Without bypass diodes, and if there is partial shading, the individual cells will actually start consuming electricity from the other cells and also cause excessive heating, which can cause the solar panel to catch on fire. However in my case, one of the diodes in the solar panel shorted out and was completely cutting off one third of the 60 cells in the solar panel.

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How To Suppress Voltage Spikes From A DC Motor With A Snubber Circuit

Being one who likes to be as self-sufficient as possible, I purchased a hand crank style grain mill. This augmented my weekly baking of Spelt bread. Now you are asking what does baking bread have to do with suppressing voltage spikes on a DC motor? That’s a fair question. Well the first time I tried grinding my wheat berries in my Wondermill grain mill, I quickly understood what they meant by ‘its not the easiest thing to do”.

This grain mill definitely needed a motor! After doing some research on motorizing grain mills I found all kinds of options. However for me, again wanting to be as independent as possible, I wanted to use a 12 volt motor instead of a 120 volt AC motor like most people do. Since my Amateur Radio station is off-grid and powered by 4 golf cart batteries, and a solar panel this seems like a logical choice.

Additionally, I had several radiator fan motors from automobiles laying around, running my grain mill on 12 volts DC made even more sense. This called for a mini road trip to the local industrial surplus shop near me, JDM Surplus to pick up some gears, pillow blocks, and chain.

Here is a video of the completed grain mill running for the first time on a gel cell battery:

As you can see in the video above, I am using a radiator fan motor. Typically these DC motors are a brushed type of DC motor, which due to the commutating of the brushes generates DC spikes that are much higher than the 12 volts that is running the motor. These spikes need to be suppressed so as not to cause damage to sensitive electronic equipment such as my Amateur radio gear, and the solar charge controller.

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My Ham Radio Go-Box Build For Portable POTA Operations

Since getting into the Parks On The Air program a few years ago, it prompted me to build my own version of what is known in the world of Amateur Radio, a Go-Box. That is a radio station that you are able to quickly grab and go at a moment’s notice. Since Amateur Radio’s justification for our frequencies is emergency communications, or EMCOMM, it makes sense that all hams have some sort of Go-box.

There are all kinds of go-boxes out there on the internet. They all have their advantages based on the operator’s needs and requirements. Being one who likes to learn from others, I spent a lot of time searching and looking at other people’s go-boxes. I then chose various features I like and incorporated them into my own go-box.

Here is what I came up with

Go Box Requirements

Plug and Play – That is plug in power, antenna and go.
Operate on HF, VHF and UHF frequencies
Compact and reasonably light
100 watts on HF frequencies
Operate on SSB, CW and Digital modes
Computer built-in
Antenna tuner

Go Box Equipment

Yaesu FT-857D
LDG YT-100 Autotuner
Raspberry Pi Computer
Signalink Sound interface
K1EL WinKeyer
Powered USB hub
Powerwerx USBbuddy 12V to 5V converter
USB GPS Dongle for grid square / time sync

Here is a photo of my completed Go-Box:

As you can see, its not actually a Go-Box, but rather what I call a Go-Frame.

The photo above shows the Yaesu FT-857D and below it the LDG YT-100 autotuner. On the right side you can see the two antenna connections that come from the rear of the FT-857D.

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How To DIY A Shortened 20 thru 40 Meter Vertical For POTA

There is something exciting doing a POTA activation where you hike in with all your gear in a pack and activating a park running QRP power. Since my original post about my first QCX-mini QRP transceiver, I now have additional QCX-mini’s that allow me to work my POTA QRP activations on 40, 30, and 20 meters. This meant I needed to build a portable shortened vertical for these bands. This particular vertical antenna build is based on my original Shortened 40 Meter Vertical but with the addition of being able to short the loading coil at the proper tap point for resonance on the 30 and 20 meter bands.

One problem I had with the original 40 meter vertical antenna, was that I used two 1/4 wave radials, which conventional wisdom says you should use with vertical antennas. On 40 meters, they are approximately 33 feet long. Which makes it more difficult to deploy the radials when in a heavily wooded POTA activation.

1/8 Wave Radials?

In doing some internet searches I discovered that it is possible to use radials that are 1/8 wavelength long — Yeah it sounds crazy to me too, but if its true, then it would greatly help the radial deployment issue on 40 meters. Granted at reduced efficiency, but I figured it was worth a shot. More on this later.

Since I already had a 20 foot collapsible fishing pole for my 40 meter shortened vertical, that is what I used for this multiband antenna. Since this was going to be for 3 bands, I wanted the loading coil low enough so that I could easily make a band change without lowering the vertical. Again, I went over to the coil shortened vertical antenna calculator page which gave me my starting points for the loading coil. Tuning this antenna for all 3 bands seemed trickier than normal. My guess is that I am using only two 1/8 wave radials.

The diagram below are my final dimensions. Your mileage may vary, but this is what I ended up with.

shortened 20 thru 40 meter vertical for pota sota activations WB8ERJ

For the loading coil form I decided to use an In Sink Tailpiece. My reasoning is this, typically people use standard PVC pipe for the coil form, which is fine, but the wall thickness of the pipe seems unnecessarily thick for my application. My main concern here was to put less stress on the wire that is the vertical part of the antenna. A toilet overflow tube is much thinner and lighter and works just fine. The outside diameter of my overflow tube is 1.5 inches. I am assuming that is a typical outside diameter. I cut the Sink Tailpiece 3 1/2 inches long, but 2 1/2″ would have worked just fine.

I used the coil shortened vertical antenna calculator based on where the coil is to be located in the above diagram and came up with a total number of turns of 33 with a tap at 13 turns from the top of the coil. If you have a different gage wire, put that in the coil shortened vertical antenna calculator instead.

Initially I built the loading coil with the calculated number of turns. As it turned out, I needed more inductance. In the photo on the next page you can see at the top of the last turn I added more wire. Lesson learned, wind more wire on to the coil than calculated.

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How To Install Equipment Into A 19 Inch Rack

I needed to install a transmitter into a 19″ equipment rack. Since it was heavy, and having installed heavy equipment into a rack I needed an easy way to do that. If you have ever installed something heavy in a 19 inch equipment rack, it is rather difficult. Even with two people. Sometimes three people are needed. This is what I came up with to make installing equipment into a rack a lot easier.

Since almost all 19” equipment racks use 10-32 screws in their side rails, get two of them and put two 10-32 nuts on the screw, and jam them together. Then clamp the whole thing in a vise.

Below is a photo of what I am talking about:

How to install equipment into a 19 inch rack

Once the screw is in the vise, take a hacksaw and cut off the head of the screw. Then cut a vertical slot with the hacksaw right where you cut off the head. The purpose of the vertical slot is so you can use a screwdriver on it. so make sure you cut the slot deep enough. You will need two of these for installing equipment into a 19 inch equipment rack.

To use them, you need to figure out which holes in the side rails you will be using for mounting your equipment in the rack. In the top most hole that you are going to use on each rail, simply screw in one these special screws.

Now its time to mount your equipment. All you do is slide your equipment’s top mounting holes on to the screws. This will properly align your holes, and all you have to do is push the bottom of your equipment up against the rack, and these two screws will hold the weight of your equipment for you. Just put in the two bottom screws first, then the rest of them into the rails of your equipment rack.

Here is a photo of one of the customized screws after the equipment is installed:

To finish the job, simply take a screwdriver and unscrew these two screws and replace them with the proper screws and you are done installing your equipment into the rack.

This article was originally posted on www.mikestechblog.com Any reproduction on any other site is prohibited and a violation of copyright laws.

DIY Your Own Equipment Rack With a Lack Table – LackRack

Recently I needed a 19″ equipment rack. But being cheap, I decided to build one. While searching the Internet, I found what is called a LackRack, which uses IKEA‘s Lack Table. However further reading revealed a couple of things that I thought were lacking in the original design of the LackRack.

Upon doing further research on using a Lack Table for a 19″ equipment rack, I found out that the legs of the Lack Table were hollow, except for the top two inches, and the bottom inch. Which would probably be ok if you only needed to rack one piece of gear, but that sort of seems to defeat the purpose of having a 19 inch rack.

What I decided to do on my 19″ equipment rack was to use metal reinforcing strips as rack rails. But first, here is a photo of the completed 19 inch equipment rack using an IKEA Lack table:

DIY 19 inch Equipment rack Lack table lackrack

I chose to mount my equipment on the inside of the legs for a neater appearance, since I was mounting metal rails on the legs of the Lack table. This also gives me a more comfortable feeling when I put my coffee cup on top of the Lack table, as coffee spills are inevitable, mounting the equipment as shown will provide more protection from such accidents.

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