Showing posts with label PowerPole. Show all posts
Showing posts with label PowerPole. Show all posts

June 18, 2016

Project: Hacking the Nomad 7 Solar Panel for Amateur Radio Use

In our earlier article, "Backpacking Amateur Radio Power: Alternatives" we explored various solutions to powering electronic devices (iPhone and an amateur radio HT) while backpacking.  The Goal Zero Nomad 7 solar panel met our requirements the best.

Goal Zero Nomad 7 Solar Panel folded up is about the size of a book
Goal Zero Nomad 7 solar panel

In this post, we explain step-by-step how we modified the Nomad 7 solar panel to make it more convenient to use in amateur radio applications.

Goal Zero has made a very handy little solar panel in the Nomad 7.  It provides power via a USB port and a 12Vdc port.  This makes it possible for us to recharge our iPhone (5V USB) and Kenwood TH-F6A (12Vdc) from the Nomad 7.  One of the great things about standards is how many of them there are. There are innumerable standards for 12v power connectors.  We prefer the Anderson Powerpole connector for our 12Vdc applications.  Unfortunately, the Nomad 7 provides 12Vdc via an 8mm connector.

Nomad 7 solar panel with its 8mm connector
Nomad 7 12Vdc via an 8mm connector

Nomad 7 with its built in USB port
Nomad 7 5Vdc via a USB connector
In order to connector our Kenwood TH-F6A to the Nomad 7 we would need to make a pigtail.  We considered purchasing Goal Zero's 8mm female to 4.7mm male pigtail assembly for $4.99 and then cutting off the 4.7mm connector and replacing it with an Anderson Powerpole.  However, this seemed like unnecessarily complex solution that would add weight and cost.  Weight comes at a high cost for backpackers.
Commercial 8mm female to 4.7mm male pigtail assembly.
Goal Zero's 8mm female to 4.7mm male pigtail assembly
After talking this over with our friends at Santa Cruz Electronics we came to the conclusion that the simplest, least weight, and lowest cost approach would be to simply cut off the 8mm male connector from the Nomad 7 and solder on an Anderson Powerpole.

Replacing the 8mm male connector with an Anderson Powerpole

Step 1: Cut off the 8mm male connector
  • Leave enough wire on the Nomad 7 to comfortably solder on an Anderson Powerpole connector.
  • Leave enough wire on the 8mm connector to solder on an Anderson Powerpole later if needed.
Step 2: Strip the coaxial cable
  • Carefully strip the black plastic sheath about 1 inch.  Take care not to cut any of the copper wire.
  • Twist the copper braid into a single wire for soldering.
  • Strip the white wire to the same length as the Powerpole connector.
  • Slide on a short length of heat shrink tubing over the coaxial cable.
Step 3: Verify the positive and negative contacts
  • Place the Nomad 7 in full sun and verify the positive and negative contacts using your volt meter.
  • Our Nomad 7 produced 15.15 Vdc in full sun (open voltage).  The Kenwood TH-F6A has a specification limit of 16V.
Nomad 7 open voltage of 15.15Vdc as displayed by a digital volt meter.
Nomad 7 open voltage (15.15Vdc)
Step 4: Solder (or crimp) on the Anderson Powerpole contacts

  • We prefer soldering the contacts to minimize resistance and assure good contact.
Soldering the Anderson PowerPole contacts

Step 5: Insert the contacts into the red/black Anderson Powerpole housing
  • Be sure to install the red side on the positive connector.
  • Use your volt meter or your Anderson Powerpole Polarity Checker to confirm that the red connector has been installed on the positive contact.
Step 6: Shrink the heat shrink tubing
  • Slide the heat shrink tubing up so it is snug with the Anderson Powerpole.
  • Using a heat source, carefully shrink the tubing so it tight around the wires.
  • This dresses the construction and provides some strain relief for the connector.

Voila!  The 8mm male connector has been replaced with a much more useful Anderson Powerpole connector on the Goal Zero Nomad 7 solar panel.  We can now connect our Nomad 7 to a wide variety of devices and cables that we have fabricated using Anderson Powerpole connectors.  This seems like such an obvious design choice it makes us wonder why Goal Zero didn't choose the Anderson Powerpole instead of the 8mm connector to begin with?  Come on world, it is time to rally around the Anderson Powerpole for 12Vdc applications.

Anderson PowerPole connectors soldered onto the Nomad 7 solar panel
Nomad 7 with Anderson Powerpole installed

In our next post (Project: Fabricating a Anderson Powerpole to 3.4mm dc connector for the Kenwood TH-F6A), we will build a pigtail for the Kenwood TH-F6A HT so we can recharge the radio's battery from the Nomad 7 via the Anderson Powerpole connector.

Good DX and 73, NJ2X

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© Michael W. Maher and NJ2X.COM, 2016.

December 31, 2012

Project: PAiA P60 Regulated Power Supply Kit

Over the  years, we have built a number of electronic devices that require a 9v DC power source.  We typically keep a box of 9v batteries on-hand though more often then not we find our cache of batteries depleted.  During a recent trip to the local grocery store we were shocked to see name-brand 9v alkaline batteries selling for nearly $5/each.  This inspired us to build a dedicated 9v power supply for use on the bench with goal of reducing our use of overly expensive 9v batteries in the coming year.  Perhaps that is a worthy New Year resolution for us all.

Regulated or unregulated?
An unregulated DC output power supply (e.g. most common wall-warts) delivers voltage without voltage control.  The DC output voltage is dependent on a couple of factors: 1) the voltage reduction transformer; 2) the amount of current used by the device receiving the power (also called load).  An easy way to identify if a wall-wart is unregulated is to simply measure the voltage without a load.  If the voltage is several volts higher than the rated voltage on the device then it is unregulated.  The typical wall-wart is often also unfiltered making it unsuitable for radio related projects.

A voltage regulator controls a power supply such that it delivers a constant voltage output over a variety of load currents (up to a maximum load).

We have a junk box full of transformers and could have had an unregulated power supply for next to nothing.  However, the ability of delivery exactly 9v for our creations was appealing and not very costly ($10 to $25 depending on the kit).  The cost of building a 9v regulated power supply is quickly recovered by simply avoiding the purchase of a few 9v batteries.

Linear or switched regulator?
Regulated power supplies can be built with linear or switched regulators.  We decided we were indifferent regarding this question.  Either would work fine for our simple needs.  We did a quick search of various kit makers to see what was offered in the way of regulated power supplies.

PAiA P60 Regulated Power Supply Kit
As a youth in the 1980's we had always enjoyed looking through the PAiA catalog of kit electronic musical instruments.  In our eyes, PAiA had the coolest looking gear hands down; though we lacked the means necessary to buy and build it.  So during our search of kit manufacturers, we were delighted to find that PAiA is still in business offering a variety of electronic kits.  A quick review of the PAiA website is all it took to find a low-cost little regulated power supply kit that fit our needs perfectly: PAiA P60 Regulated Power Supply Kit

The P60 kit provides a circuit board and all components except for the 3-pin (TO-220 package) voltage regulator.  This allows the builder to select the specific regulator / voltage that meets his needs (5v to 24v).  Input voltage can be either AC or DC and needs to be 2v or 3v higher than the target output voltage (depending on the regulator chosen).  We liked the fact that terminal blocks were provided for both input and outputs.  This would make it very easy to connect and disconnect from various projects.  We also appreciated the on-off switch and power-on LED indicator.  The power supply is rated for up to 1A which would be more than enough for our 9v projects.  We had a couple of 7809 voltage regulators on-hand so this kit would be a perfect fit.

The kit was a breeze to assemble following the guidance provided by the kit product sheet.  We decided to substitute a blue LED for the one that came with the kit out of personal preference.  We are Anderson PowerPole connector enthusiasts so it was natural to wire up an Anderson PowerPole to the input block.  This would make it easy to connect the to our 13.8v DC Astron RS-35M power supply that we use in the shack or in the car using our home-brew car power to Anderson PowerPole adapter.

On the output block we connected one of our home-brew 9v battery clips.  This would make it easy to connect to our electronic 9v creations.  To use a battery clip as a power source (simulated battery) requires reversing the polarity.  That way when two clips are married together the voltage polarity will be correct. 

The power supply has worked flawlessly in our shack since it was built.  We really appreciate the convenience and economy of powering up our 9v creations free of the hassle and expense of 9v batteries.  We are using our 9v power supply at the time of this writing to power KC2VSR's 3D Xmas Tree which gives a little holiday charm to the shack.  We haven't mounted it in a case so far.  Looking for something that is both free and suitable to repurpose.

By the way, we found an excellent resource for power supply terminology.  It is interesting to browse through the page.

Good DX and 73, NJ2X

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© Michael W. Maher and NJ2X.COM, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.

December 28, 2012

Project: Anderson Powerpole Polarity Checker

Ward Silver's (N0AX) article, "Hands-On Radio: Experiment #120: Power Polarity Protection", in the January 2013 issue of QST included a circuit diagram for a 12v polarity checker.  Inspired by the diagram, we headed to workshop on a Friday evening to fire up the soldering iron and fabricate our own Anderson Powerpole polarity checker using junk-box parts.

Schematic of a polarity checker with a 1k Ohm resistor and two LED's one red and one green
Powerpole Polarity Checker Circuit Diagram
From Hands-On Radio: Experiment 120: Power Polarity Protection, January 2013 QST; copyright ARRL

We are big fans of Anderson Powerpole connectors and recabled our radio gear with the connector sometime ago.  A polarity checker would be a very useful item to have around the shack and in a go-kit.

Step 0: Round up the parts and tools

A well-stocked junk box and workshop will likely yield all the necessary parts needed to build the polarity checker.  A few minutes of scrounging around our workshop is all it took to find the parts for this project.
  • Green LED
  • Red LED
  • 1k Ohm resistor 1/4W
  • Pair of Anderson Powerpole connectors
  • Junk box plastic part to turn into an end-cap
  • Hot glue gun
  • Soldering iron
  • Shrink wrap tubing (small diameter)
  • Wire snips

Step 1: build the circuit on a solderless breadboard

We find it helpful to first build a circuit on a solderless breadboard prior to assembly and soldering.  This approach helps confirm the junk-box parts are still functional, the circuit works as advertised, as well as verifying the orientation of parts having polarity (e.g. the LED's in this project).  This circuit is very simple.  The key is to make sure the LED's are wired together in opposite polarity.

Anderson PowerPole polarity checker circuit being tested on a solderless breadboard prior to assembly.
NJ2X first built the polarity checker on a solderless breadboard as a test

Step 2: Prepare the end-cap

We found some sort of plastic cap in our junk box that would marry up perfectly to the back side of a pair of Anderson Powerpole connectors.  We drilled four small holes in the top of the cap to pass the LED's leads through.
Anderson PowerPole polarity checker cap - four holes being drilled for the LED wires to pass through.
NJ2X drills four holes in a small cap for the LED leads

 Step 3: Solder the components together

Insert the leads of the two LED's on the top of the cap.  Solder the leads and resister together per the wiring diagram.  Use shrink wrap tubing to insulate the leads from each other to prevent a short.  Solder a short red wire and back wire to the leads.  Again use shrink wrap tubing to insulate the connections.  Solder the Anderson Powerpole connectors onto the wire ends.  Be sure the Powerpole positive and negative are tied together in the correct configuration, "Red Right Up".  Test the circuit to confirm it is working before proceeding with final assembly.

Anderson powerpole polarity checker in a vice while be fabricated
NJ2X testing the soldered polarity checker prior to final assembly

Step 4:  Final Assembly

Fill the cap with a generous amount of hot glue.  You want enough glue to assure a solid mechanical connection and prevent the wires from moving or being stressed during use.  Press the wire and Anderson Powerpole connectors into the cap and hot glue.  Let the glue cool and harden.  Test again to confirm the circuit is functional with both correct and reversed polarity.  We used a label maker to add our call sign to the outside.

Fully assembled Anderson PowerPole polarity checker.
NJ2X's Anderson Powerpole polarity checker fully assembled

We shared a picture of the finished product with N0AX and he pointed out that it looked a little like a rabbit.  My son, KC2VSR gave the polarity checker a funny bunny face to really set off the effect.  We had a good laugh and decided to call the polarity checker, "Bunnicula".  Ham radio is really a wonderful hobby to share with kids.

fully assembled Anderson PowerPole polarity checker with a cat-face drawn on it for humor.
NJ2X's Homebrew Anderson Powerpole Polarity Checker

Voila!  There is our build of a very handy 12v Anderson Powerpole polarity checker.  Use the polarity checker before plugging into an unverified Anderson Powerpole connector.  This simple test may save your equipment from damage.  A lit green LED denotes correct polarity and lit red LED indicates reversed polarity.

There are at least a couple of potential failure modes that would cause the polarity to be reversed on a pair of Powerpole connectors.  One potential failure is that the red wire terminating at the power supply was accidentally connected to the negative terminal.  Another possibility is that the Powerpole connectors were snapped together with the incorrect orientation.

For example, when volunteering during an emergency and you need to recharge your HT's battery from the HQ emergency power via a Powerpole.  If you plug into it without checking polarity you may end up with a dead HT if the cable was wired incorrectly to the supply.

Not all cars are wired so the center of the cigarette lighter connector is positive.  If you use an Anderson Powerpole to Cigarette Lighter adapter on an unfamiliar vehicle you may be in for an unpleasant surprise when you connect your rig and the reversed polarity causes damage.

An additional use of the polarity checker is a quick power cable or connector continuity checker.  We plan to put our polarity checker to good use in the shack testing all new cables and Anderson Powerpole connectors that we build for mechanical contact, continuity, and polarity.  In the past, we have simply used a multimeter which didn't confirm that the connector makes proper electrical contact when connected mechanically to another Powerpole.

Good DX and 73, NJ2X

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© Michael W. Maher and NJ2X.COM, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.

October 14, 2012

How To: Lock Together Anderson Powerpole Connectors

Anderson Powerpoles are a wonderfully useful invention for radio amateurs.  They are connecting power to more and more amateur radio equipment every day and have become the defacto standard for 12v power connection.  Interestingly, radio manufactures are still catching up on this trend.

When two Anderson Powerpole connectors are connected together they snap together but are not locked.  This allows quick connect / disconnect and works just fine in many situations.  However, there are several situations where locking the connectors together is required.
  • The power cable is subject to movement which could work the connection apart.
  • The power cable with a vertical orientation and connection where gravity could pull the connection apart.
  • The power cable and connection is being pulled during routing which could cause a disconnect.
There are commercially available retention clips to lock Powerpole connectors together.  These cost around $0.60 / clip.  Hams are nothing if not thrifty.  Why buy expensive clips when there is an alternative way to lock together Anderson Powerpole connectors for next to nothing?

The secret is to use a suitably sized wire tie.  Wire ties are cheap, fast, easy, and work perfectly to lock Powerpoles together.

Select a wire tie slim enough to pass through the small holes on the Anderson Powerpole connectors.
Anderson PowerPole connectors and wire tie

Just slip the wire tie through the holes on each Anderson PowerPole. 
Anderson Powerpole connectors locked together with aid of a wire tie

Voila!  The two Anderson Powerpole connectors locked together.  To disconnect just give the wire tie a quick snip with wire cutters.


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January 29, 2012

Project: Anderson Powerpole to 2.1mm Connector Pigtail

When building our KN-Q7A Single Band SSB Transceiver Kit we realized after starting that we lacked the necessary power 2.1mm connector to supply 12v to the power jack.

From a design standpoint we decided to construct an Anderson Powerpole to 2.1mm connector pigtail.  This was a natural choice since we previously converted our radios and cabling to Anderson Powerpoles.  A 2.1mm connector to Anderson Powerpoles will give us maximum flexibility to move the radio from one power source to the next (e.g. battery, car power, shack power supply, bench power supply, ....).  The commercially available Anderson PowerPole to 2.1mm cable costs at the time of this writing about $5.00 plus shipping. 

We decided it would be more ecconomical and far more fun to build the pigtail cable ourselves.  A home-brew cable would also give us an opportunity to incorporate a few improvements in design over the commercially available cable.
One of the improvements we wanted to include on the cable was an RF choke.  We decided to add a ferrite (from the junkbox) to the pigtail to help minimize RF travelling over the power cable.  This would potentially be useful when running the radio from a car or other noisy source.

Pigtail construction in progress with ferrite bead
To protect the ferrite bead and assure the wire loop would stay nice and tight we added heat-shrink tubing around it.  We also added a section of heat shrink tubing to the end next to the Anderson Powerpole connector as a strain relief and to dress the cable nicely.

Finished 2.11mm to Anderson Powerpole Pigtail with ferrite bead for RF supression
After completing the wiring we ran a quick series of continuity tests with our multimeter to verify that the cable was fully functioning and without any shorts or other defects.  For our project, we needed the 2.1mm center to be positive.
The final product came out really looking and functioning perfectly and cost very little.  Having a completed cable enabled us to continue on building and testing our KN-Q7A Single Band SSB Transceiver Kit - Step 2: Audio Amplifier.

By Michael W. Maher (NJ2X)
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© Michael W. Maher and NJ2X.COM, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.

November 11, 2011

Project: Car power adapter to Anderson Powerpole

Conservation is the act of preservation, protection, or restoration of the natural environment.  We hams are conservationists as we tend to be a thrifty lot and regularly re-purpose and reuse materials for our hobby.  Why throw something into a landfill when it can be made into something useful?  Through creativity and technical know how we conserve materials (and funds).  The smell of solder and a few minutes in the workshop is great fun too!
In this article we share a useful and simple project to convert an unneeded car power cable to an Anderson Powerpole adapter.  We cabled all of our radio gear for Anderson Powerpoles sometime ago and have been glad we did so ever since.  Anderson Powerpoles offer many compelling reasons for adoption:

Flat Wiping Contact System
  • Minimal contact resistance at high current, wiping action cleans contact surface during connection/disconnection.
Colored Modular Housings
  • Provides visual identification of proper mating connector.
Molded-in Dovetails
  • Secures individual connectors into "keyed" assemblies which prevents mis-connection with similar configurations.
Defacto Standard
  • Anderson Powerpoles have emerged as the defacto power connector standard in the amateur radio community.
  • This means it is easier to power your equipment at hamfests, club meetings, field day, emergency communications, ....
Unfortunately, vehicles provide power for passé "cigarette lighters" and not Anderson Powerpole connectors.  Come on Detroit, time to get with it and provide Anderson Powerpole outlets in your vehicles.  A boring solution would have been to buy a couple of  vehicle power to Anderson Powerpole adapters which typically sell for about $15.00 at ham fests.  However, a quick survey of our junk box revealed several unused vehicle power cables which could be readily adapted to Anderson Powerpole connectors for very little cost.

Materials and Tools
1 - pair of Anderson Powerpole contacts (black and red)
1 - 2-inch length of suitable heat shrink tubing
1 - vehicle power cable (AKA cigarette lighter power cable)
Wire cutters
Wire stripper
Soldering iron
Rosin flux
Electrical Solder

Step 1: Prepare the cable by snipping off the unneeded end.

Step 2: Strip both wires about 5/16 inches (7.9 mm).

Step 3: Brush on rosin flux and tin the wires.  Be careful not to apply too much heat and melt the insulation.  If you do melt the insulation a little, just trim up the exposed wires to maintain the 5/16 inch length.

Step 4: Slip the cable through the 2 inch length of heat shrink tubing.  This provides a nice dressed looking cable.  Additionally, the heat shrink tubing will provide strain relief.

Step 5: Melt rosin flux into the Anderson Powerpole connectors.  Solder the connectors onto the tinned wires.

Step 6: Using the multimeter, determine the vehicle adapter's center contact.  Install the red Anderson Powerpole's by inserting the contact and wire into the housing from the rear. Position contact and push forward so that contact slips under the barrier and snaps over the end of the retaining spring.  Tug slightly to make sure contact is locked in place.

Step 7:  Install the black Anderson Powerpole's by inserting the contact and wire into the housing from the rear.  Position contact and push forward so that contact slips under the barrier and snaps over the end of the retaining spring. Tug slightly to make sure contact is locked in place.

Step 8: Using the multimeter, confirm continuity of red contact with the vehicle adapter center conductor.  (and no continuity with the outer spring contacts).  Confirm continuity of the black contact with the vehicle adapter out spring contacts (and no continuity with the vehicle adapter center conductor).

Step 9: Dovetail the two connectors together and interlock the red and black Anderson Powerpole by slipping the keyed parts together as pictured above.

Step 10: Slide the heat shrink tubing forward as close to the Anderson Powerpole connectors as possible.  Use a blow dryer or other heat source to gently shrink the tubing until snug.  Avoid burning or melting the heat shrink tubing.

Voila!  That is all it takes to make a vehicle power / Anderson PowerPole cable adapter.  This is a fun and easy project that has the added advantage of saving money.

A few other considerations.
  • Since it is possible that vehicle manufacturers may reverse polarity of the power output, be sure to use your multimeter or Anderson Powerpole Polarity Checker to confirm that red Anderson Powerpole connector is indeed positive on your vehicle prior to using the cable.
  • We built our cable for use with low power devices.  Be sure to use a cable suitable for the current your device will draw. 
  • An in line fuse or fuse integrated into the tip of the vehicle power adapter is a good idea. 
  • Adding a ferrite bead or two can do wonders with keeping RF off the power cable (our junk box cable came with a ferrite already installed).

By Michael Maher (NJ2X)
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© Michael W. Maher and NJ2X.COM, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.