Showing posts with label APRS. Show all posts
Showing posts with label APRS. Show all posts

June 11, 2016

Backpacking Amateur Radio Power: Alternatives

In our prior post (Backpacking Amateur Radio Power: Requirements) we discussed our requirements for powering our electronics in the backcountry including an HT and an iPhone.  We defined our requirements in the form of a user story with acceptance criteria.


USER STORY: As a backpacker, I need a way to use my TH-F6A radio and iPhone 6 during my backpacking trip and not run out of battery before the end of the trip so that I can have fun with the devices during the trip and have them ready for use at any time during the trip in the event of an emergency to call for help.

ACCEPTANCE CRITERIA:
  • Must allow the backpacker to use the device a little or a lot as needed.
  • Must be flexible enough to allow the backpacker to use the solution regardless of duration (our typical backpacking adventures range from from 1 night to 15 days).
  • Must not add significant weight to the pack (i.e. < 1.5 lbs / 0.68Kg).
  • Must be able to maintain power for an iPhone via the USB connection (5Vdc USB power).
  • Must be able to maintain power for a Kenwood TH-F6A via the 12Vdc connection.

In today's post, we will explore potential alternative solutions and compare them against our requirements.

Option 1: Conserve the battery

Pros
  • Practical approach
  • No cost
  • No added weight
Cons
  • Conserving the battery means using the devices sparingly over the trip.  For the iPhone it means leaving the device powered off during the hike and powering it on when needed.  Not very convenient for snapping photos while trekking.  Keeping the HT powered off is a bit more feasible.  However, we like to use the radios in our backpacking group to keep the front and rear in communication as we go to since we tend to string out a bit.
  • This approach doesn't meet our acceptance criteria of being able to use the devices as much or as little as needed during the trek.

Option 2: Pack extra batteries

Pros
Cons
  • On longer trips, one set of extra batteries may not be enough.
  • Some conservation of battery power is still required.

Option 3: Pack a portable generator: BioLite Wood Burning Campstove

Pros
  • Claims to provide portable power (USB).
Cons

Option 4: Pack a portable generator: K-TOR Pocket Socket Hand Crank Generator

Pros
  • Possible to recharge both USB and 12Vdc batteries.
  • The weight is under the limit per our acceptance criteria (1.0 lbs/0.45Kg < limit of 1.5 lbs/0.68Kg)
  • Cost is reasonable at $54.00 on Amazon.com
Cons
  • The K-TOR Pocket Socket Hand Crank Generator had mixed reviews on Amazon.com.  From the reviews is sounds like hand cranking is laborious and takes a long long time to recharge.  This is a material consideration since backpacking can be physically exhausting.  Having difficulty imaging cranking for hours after a day of backpacking 16 miles with elevation changes.
  • Requires packing the transforms for iPhone and HT.  This adds additional weight.

Option 5: Pack a solar panel: Goal Zero Nomad 7

Pros
  • Recharges USB devices.
  • Recharges 12Vdc devices.
  • Lightweight at 1.4 lbs/0.64Kg which is less than our acceptance criteria limit of 1.5 lbs/0.68Kg.
  • Easy to use and requires no physical effort to generate power.
  • Cost is reasonable at $77.31 on Amazon.com
  • Solid reviews on Amazon.com.
  • Well made and durable.
Cons
  • Need direct sunlight to recharge.  We have sunshine in abundance here in California so this isn't a material concern.

Option 5: Pack a solar panel: Goal Zero Nomad 7 is the clear winner among our alternatives.  It fits the requirements very well.  We are looking forward to putting it to the test.


In our next post in this series, "Project: Hacking the Nomad 7 Solar Panel for Amateur Radio Use" we will show step-by-step how we modified our Nomad 7 to make it more convenience to use with our Amateur Radio setup.

We will review how well the whole setup worked on a challenging backpacking backcountry adventure in our final post in the series.


Good DX and 73, NJ2X


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

June 4, 2016

Backpacking Amateur Radio Power: Requirements

So how do you bring an iPhone and HT on a backpacking trip and use them without running out of battery before the end of the trip?  In this post, we explore this question and the related requirements.

We have been doing a lot of backpacking lately in the mountains of Northern California.  Backpacking is great exercise, physically challenging, and a great way to immerse yourself in nature.  A backpacker must carry everything needed for the trek including food, water, shelter, clothing, first aid, and personal items.  Our 3-day/2-night pack weighed in around 30 lbs / 13.6 Kg.  Weight comes at a big cost to a backpacker, so the objective is to minimize.

When trekking in the backcountry there is often no mobile phone coverage.  Mountain peaks sometimes provide a line of sight to a faraway cell tower which can yield one or two bars of signal.  In our experience, the valleys are barren of mobile phone signal.  We still carry our cell phones on backpacking trips because the phone provides a good camera and can also serve as a potential emergency communication device.  Being able to summon help when you need it most is invaluable.

Amateur radio VHF/UHF repeater coverage in the backcountry is more readily available than cell phone coverage in the places we have been hiking.  This makes the amateur VHF/UHF HT a valuable companion on a backpacking trip.  In an emergency situation, communication can make a tremendous difference in the outcome.

We programmed our Kenwood TH-F6A tribander radios with as many repeaters as we could covering the areas we like to travel and backpack in Northern California.  The TH-F6A transmits 5W on the 144 MHz, 220 MHz, and 440 MHz amateur bands. We also programmed them with the various simplex calling frequencies.  We bring them on every trip.  Sometimes we also use our TH-F6A with our TinyTrak4 TNC and GPS for APRS tracking.  The TH-F6A has a wide-band receiver which allows us to listen to broadcast radio in camp (AM/FM).

Kenwood TH-F6A hand held transceiver
Kenwood TH-F6A Triband VHF/UHF HT is perfect for backpacking

The challenge with bringing electronic devices on a backpacking trip is using them without running out of power before the trip ends.  We don't simply want to throw the devices into our packs powered off during the trip in order to save the battery.  So what are the requirements for the solution?  We defined our requirements in the form of a user story with acceptance criteria:

USER STORY: As a backpacker, I need a way to use my TH-F6A radio and iPhone 6 during my backpacking trip and not run out of battery before the end of the trip so that I can have fun with the devices during the trip and have them ready for use at any time during the trip in the event of an emergency to call for help.

ACCEPTANCE CRITERIA:
  • Must allow the backpacker to use the device a little or a lot as needed.
  • Must be flexible enough to allow the backpacker to use the solution regardless of duration (our typical backpacking adventures range from from 1 night to 15 days).
  • Must not add significant weight to the pack (< 1.5 lbs/0.68Kg).
  • Must be able to maintain power for an iPhone via the USB connection (5Vdc USB power).
  • Must be able to maintain power for a Kenwood TH-F6A via the 12Vdc connection.

Now that we understand our requirements, we are ready to explore potential solutions in the next article.


Good DX and 73, NJ2X

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

February 23, 2014

Project: Tiny Mint Tin Switched 9v Battery to Anderson Powerpole

We enjoy using a Byonics TinyTrak4 as an APRS TNC when operating portable with an HT in the back country.  This remarkable device, when coupled with an HT, transmits GPS position to amateur radio APRS receivers that pass the information along to the Internet.

http://www.byonics.com/tinytrak4/
Byonics TinyTrak4 TNC


The Byonics TinyTrak4 can run on 9v to 12v and the adapter cable is wired with Anderson PowerPole connections.  We prefer to keep our pack weight to a minimum when hiking so a 9v battery is an excellent choice.

Our first design was to simply solder a 9v battery clip to a pair of Anderson PowerPole connectors.  This worked well; however, we found it was also rather fragile and it didn't take long for the whole thing to fall apart.

While rummaging around our junk box we noticed a diminutive mint tin slightly larger than a 9v battery and this became the inspiration for an improved battery pack design.  The basic idea is to use heavier gauge wire for the Anderson PowerPole connectors and hide the battery and fragile 9v clip inside the tin.  Adding a switch would provide a convenient way to switch power on/off (there is no switch on the TinyTrak4).

NJ2X - mint tin transformed into a switched 9v battery to Anderson Powerpole


NJ2X - mint tin open revealing 9v battery and connections

 Steps:

  1. With a 9v battery in the enclosure, layout where to place the exit holes for the wires and switch
  2. Drill a hole large enough for the two wires plus a little margin for heat shrink tubing
  3. Drill a hole for the switch.  If necessary, drill a semi-circle on the lid edge so it will close with the switch installed (see picture).  Remove the burrs.
  4. Solder the positive wires to the switch
  5. Solder the negative wires together
  6. Wrap all the contacts in heat shrink or electrical tape to prevent short circuits with the case or battery
  7. Tie a simple knot using the black and red wire that will exit the box
  8. Pass the black and red wires through the exit hole leaving the knot on the inside of the box.  This will prevent strain on the battery clip and contacts.
  9. Slide a short length of heat shrink over the two wires exiting the box
  10. Solder the Anderson Powerpole ends on the wires and clip into the Powerpole connectors
Correct configuration of Anderson Powerpoles: "Red Right Up"


Voila!  A handy little 9v battery to Anderson Powerpole device.  Perfect for powering up a Byonics Tiny Track4.


NJ2X's portable APRS setup Kenwood TH-F6A, Byonics TinyTrak4, Byonics GPS2, and home brew 9v to Powerpole battery pack

Good DX and 73, NJ2X

By Michael W. Maher


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© Michael W. Maher and NJ2X.COM, 2014. 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.

August 8, 2013

FCC Technician Exam Question Of The Day (T8D02)

Q) What does the term APRS mean?

A) Automatic Position Reporting System

NJ2X Notes:
APRS (Automatic Packet Reporting System) is a system developed by Bob Bruninga (WB4APR)  which uses amateur radio to transmit position reports, weather reports, telemetry, and messages between users.  A very useful APRS related tool is Google Maps APRS.