Tag Archives: WD8RIF

Portable Power Primer: A beginner’s guide to selecting the best battery option for your field radio kit

The following article originally appeared in the April 2021 issue of The Spectrum Monitor magazine:


I’ll admit it:  I’m a massive fan of field radio.

In 2020, I easily spent a total of 100 hours outdoors with my radios activating a total of 82 sites for the Parks On The Air (POTA) program alone. This doesn’t include hours and hours of SWLing (shortwave radio listening). It’s been great.

Taking radios into the field is so much easier to do today than it was in, say, 1985 or earlier, because we have so many more options for powering our gear in the field. Not only have radios become more efficient in operating off of battery power, but we now have so many affordable and lightweight rechargeable battery choices on the market.

In the following article, let’s take a look at some portable battery power options for your radio gear. By “portable,” I’m talking power options for those of us who load a backpack or carry case and head to the field.

To keep the scope of this article in check, I’m also going to focus only on rechargeable battery options. And rather than get bogged down in the nuances of battery chemistries, we’ll focus on the end result––the pros and cons of each battery type, and how practical they might be for your field application.

In addition, I’ll also limit discussion to batteries that can be purchased of-the-shelf rather than addressing homebrew options. While I love building things, I’m very cautious when dealing with battery charging because if not done correctly, the results can be dangerous. I prefer obtaining products from trusted suppliers who thoroughly engineer and test their equipment.

Let’s take a look at several types of batteries, and speak to their advantages…as well as disadvantages. Then––as we summarize our findings––let’s discuss how to choose the right option for your needs.

Consumer-grade rechargeable batteries

Let’s begin by talking about the lowest-hanging fruit in terms of portable power: everyday rechargeables in the form of 9V, AA, AAA, C, and D cells.

While, admittedly, these batteries are not typically an option because of their limited capacity and energy density, they can still be a very practical power source for portable receivers and even a few QRP transceivers.

Rechargeable battery chemistries have improved with time, thus I no longer purchase nickel-cadmium (Ni-Cd or NiCad) or legacy nickel metal hydride (NiMH or Ni–MH) batteries.

 

These days I almost exclusively purchase low-self-discharge nickel metal hydride (LSD NiMH) batteries, specifically, Panasonic Eneloop batteries (Amazon affiliate link).  Although they’re a pricey option compared with generic NiMH batteries, and might even be overkill for certain applications, I do love the shelf life of Eneloops.

Of course, the benefit here is Eneloops have that low self-discharge. They will maintain charge better at rest (i.e., when not in use) than legacy NiMH or NiCad batteries. From my real-word usage, I’m convinced that Eneloops also demonstrate better longevity over numerous charge/discharge cycles than many others.

All of my portable shortwave receivers that accept AA or AAA batteries are powered by Eneloops exclusively.

And although I’ve never done this myself, it is also possible to power highly-efficient QRP transceivers with Eneloop batteries, so long as you use a multiple battery holder to increase voltage and capacity to match both your rig and your desired amount of operating time.

WD8RIF’s AA battery holder

Keep in mind, though, that most transceivers will require a block of at least ten AA batteries to reach a voltage around 12 VDC. As you might imagine, it can be cumbersome after using your radio in the field to remove all ten of these batteries and charge them in a charger that can only hold, say, four batteries at a time. I personally prefer other options, but this one is certainly a fairly affordable, safe, and accessible option.

Note that in recent years, Panasonic started offering Eneloop Pros: while pricier than standard Eneloop batteries, they offer slightly higher capacity at the expense of overall longevity (roughly 500 versus 2100 total charge/discharge cycles). Since the voltage is the same, I’ve never felt the need to use higher-capacity Eneloop Pros.

Rechargeable Panasonic Eneloop AA batteries (non-Pro version):

  • Price: $2.25 – $4 US per battery, depending on the number in the package
  • Weight: 4 grams/.4 ounces per cell
  • Voltage: 1.2 V each
  • Longevity: Excellent, up to 2100 charge/discharge cycles
  • Ease of recharging: Simple via Eneloop OEM chargers
  • Solar- charging option: Eneloop originally marketed solar chargers, but doesn’t seem to do so presently

Sealed Lead Acid (SLA) Batteries

When I first became a licensed ham radio operator in the late 1990s, sealed lead acid batteries were the primary battery power source used for field radio operation.

At the time, these batteries were one of the best options for portable radio use because they could be purchased in a variety of sizes (based on amp hour capacity), and unlike flooded lead acid batteries, they required no maintenance––and being sealed, did not outgas.

While I’ve owned everything from 3 Ah to 15 Ah SLA batteries, I found the once-ubiquitous 7-8 Ah size to be the “sweet spot” in terms of portability and capacity.

SLA batteries are still among the most accessible high-capacity batteries on the planet. No matter where you travel, it’s likely you’ll be able to hunt them down in any hardware or electronics store. Our small local hardware store has a wide selection of these at their battery kiosk.

What are some of the pros of these batteries? In terms of “bang for buck,” the SLA is still hard to beat. You can purchase a quality 7.2 Ah 12-volt SLA battery for about $18-20 US (affiliate link). This would be more than enough battery to power a typical QRP transceiver for many hours on end. Chargers are also inexpensive––you can purchase a dedicated charger for about $10-15 US. Not bad.

In addition, 12-volt batteries are nearly ideal for amateur radio use since most transceivers are designed to operate with 12-13.8 volts DC +/- a modest margin.

There are some negatives compared with more modern battery chemistries, however. For one, SLA batteries are much heavier than the batteries we’ll discuss in the following sections. After all, they’re (still) made of lead!   In addition, the battery’s longevity will be negatively impacted if you discharge it too deeply.

With that said, if you take care of an SLA battery, it can give you five or more years of service life in the field, yielding an excellent value for the modest investment. If you have an application that requires relatively little capacity from the battery, you might get a very long service life, indeed. In 2011, I built a remote antenna tuner box around an LDG Z11 Pro ATU and a discarded 7Ah 12V SLA battery. At the time, this battery could no longer hold voltage long enough to be reliable in the field, but I knew the Z11 Pro requires very little in the way of power, so I thought I’d try it as a power source anyway. Since the remote ATU box isn’t near an outlet, I charge the SLA battery with a 5-watt solar panel I purchased used at a hamfest with a Micro M+ charge controller. A decade has now passed, and that SLA battery continues to power the Z11 Pro even through seasonal temperature variances of -10F/-23C to 90F/32C. Not bad! Again, keep in mind this application works because the Z11 Pro is so flexible in terms of power requirements––it’ll operate on 6-16 volts DC at 300 mA with a 20 uA standby current.

Clearly, SLA batteries are affordable candidates for back-up power in the shack during occasional power outages.

  • Price: Most affordable option per Ah of the batteries listed here
  • Weight: By far, the heaviest of all the battery options in this article
  • Voltage: Various, but 12VDC is very common
  • Longevity: Very good if properly maintained
  • Ease of recharging: Easy, via simple charge controllers
  • Solar charging option: Multiple types of charge controllers can be used with SLA batteries; among the listed batteries, the easiest and least expensive to charge via solar

Lithium-Ion (Li-ion)

 

Without a doubt, lithium-ion batteries have revolutionized the consumer electronics world.

Why are they so popular?

First of all, their construction allows for a variety of form factors ranging from cylindrical cells to slim packs and pouches so thin they can fit in an ultra-thin mobile phone, eReader, or tablet. They’re the easiest type of battery to accommodate in compact consumer electronics, and indeed, they power most of the consumer electronics we’ve put to use in the last decade.

Secondly, they have a very high energy density, thus pack a lot of capacity for the size and weight. Indeed, if size and weight are your primary requirements, li-ion batteries should be high on your list.

In addition, Li-ion batteries are ubiquitous and affordable because they’re used in so very many applications.

There are negatives, though, with these power sources. First and foremost, they’re very sensitive to over-voltage and over-current events that initiate a thermal runaway. To prove this point, I’ll share some first-hand experience from the early days of large lithium-ion packs…

Li-ion Horror Story

In 2011, I evaluated a lithium-ion battery pack with integrated 5V USB chargers and even a simple one-outlet inverter from one of the big names in portable power systems. At the time, this was a new battery pack and a relatively new technology, at least in terms of the energy density and compact size. After receiving the battery, I charged and discharged it perhaps twice during testing. I had a flight scheduled from North Carolina to California, and decided I’d take it in my carry-on bag to power my laptop in flight. It worked fine on the flight to KSFO. Once there, I recharged it.  On my return flight, it simply didn’t work. I thought perhaps I hadn’t plugged it in properly, or that the hotel outlet I used didn’t work. Upon arrival I emptied my travel pack onto the bed and plugged in the battery pack; it indicated it was taking a charge.

After doing a few projects around the house, I went back up to the bedroom and was greeted with an overpowering smell––almost like the pungent chemical odor of nail polish remover. I looked everywhere for the source of the odd smell.  Finally, I located it:  it seemed to be coming from the battery pack. Upon examination, I could tell the battery had begun to swell. As I lifted it up, I noticed that the bottom portion was essentially in a state of melting. As quickly as I could, I unplugged it and removed it from the room. I then discovered that in the thermal runaway process, it had begun burning through the sheets and mattress of the bed. Shocked, I suddenly realized it could have burned down my home.

Keep in mind, I was completely new to this battery technology, and this was years before thermal runaways made the news and airlines began restricting their transport. To my relief, the company from which I purchased the pack ended up pulling that model off the market, and even reimbursed me for the mattress and bedding. But it was a hard lesson learned.

If I’m being perfectly honest, this lesson had a major impact on my willingness to experiment with Li-ion battery packs.

The problem with the model of pack I had purchased was not the battery chemistry or construction, per se, but the charge controller). The fact is, Li-ion batteries require millivolt accuracy and a number of protections to detect and stop thermal runaway. Battery packs with multiple cells need a battery management system (BMS) that also balances the cells and monitors them closely. Fortunately, most manufacturers of the technology now understand this.

Modern Li-ion cells and chargers are much safer and more stable 

Since then, Li-ion battery chargers have become both orders of magnitude safer and more effective. Still, I only charge these batteries on a surface which, should the battery be tempted to melt down, would be less likely to be damaged or serve as a fire hazard. I also never leave them unattended during charging.

With that said, I don’t think Li-ion batteries are to be feared. Obviously, many of us walk around with one tucked in our pocket all day––in our smartphones! They’re generally considered very safe now.  Of course, I’d only buy the best and would steer away from the lowest-costs units you might find on eBay and Aliexpress, as many of these products are made in places with little oversight or regulation.

Another interesting fact about Li-ion battery packs is that since their voltages are usually available in multiples of approximately 3.6 volts (e.g., 3.6, 7.2, 10.8, 14.4 and 18 volts), they are not always ideally suited for radios that require 13.8V input power. Some packs, however, have circuitry that provides an output voltage closer to your desired amount.

One Lithium-ion battery pack I’ve been using with my Mountain Topper MTR-3B, Elecraft KX2 and KX3 transceivers is a (very affordable) TalentCell rechargeable 3000 mAh Li-ion battery pack that provides both 12V and 5V USB power. It has built-in charging circuitry and is very compact. I purchased mine for about $25 on Amazon.com, and have been very pleased with it so far.

Summits On The Air operators often place priority on smaller-sized and lighter-weight power sources, and thus turn to Li-ion battery packs. Many SOTA friends have invested in high-quality balance charger/dischargers to maximize the life of their batteries, and have been happy with the performance they receive. A quality charger may costs upwards of $60, but is worth the investment if you choose Li-ion batteries as your portable power of choice.

  • Price: From affordable to pricey, depending on capacity and charger investment
  • Weight: The lightest weight portable battery options in this list
  • Voltage: Often in multiples of approximately 3.6 volts: (3.6, 7.2, 10.8, 14.4 and 18VDC)
  • Longevity: Good. Typically around 400-500 charge cycles if properly maintained
  • Ease of recharging: Simple, if a self-contained pack; more complex, if using multiple cells that need balancing
  • Solar charging option: Not advised (yet). There are a number of homebrew Li-ion solar charging projects on the web, but I believe this battery chemistry fares better with a balance charger connected to a stable AC power supply.

Lithium Iron Phosphate (LiFePo4/LFP)

I typically use my 15 Ah LiFePo4 battery pack when powering transceivers like the Mission RGO One that can push 55 watts of output power. I also use this battery to power my Elecraft KXPA100 amplifier on Field Day.

The final type of battery chemistry we’ll cover here is my favorite of the bunch.

There are good reasons why Lithium Iron Phosphate batteries have become one of the choice rechargeable batteries for field radio use.

  • LiFePo batteries are inherently stable and safe
  • They offer a longer cycle life than that of other Li-ion, NiMH, NiCad, or Lead Acid batteries–thousands of charge cycles as opposed to hundreds
  • LiFePO batteries have an excellent constant discharge voltage
  • LiFePo batteries use phosphates––as opposed to cobalt or nickel, which are supply-constrained and carry heavier environmental concerns
  • LiFePo batteries have a lower self-discharge
  • LiFePo batteries are very lightweight compared to SLA batteries
  • 3.2 V nominal output voltage means that four cells can be placed in series for a nominal voltage of 12.8 V, near ideal for most field radio gear

Any cons? Yes…while they’re lightweight, LiFePo4 batteries aren’t as compact as Li-ion battery packs.  But the primary negative here is the price.  At time of print, LiFePo4 batteries have the highest cost per Amp hour of the batteries discussed in this article. With that said, due to the excellent longevity of these batteries, the LiFePo may be the most cost effective option in the long term.

LiFePo4 battery systems sport built-in battery protection modules to address concerns like over-voltage and balancing.

How do LiFePo batteries stack up?

  • Price: One of the pricier options, when you include the battery and charger
  • Weight: Very light weight, but size tends to be larger than comparable Li-ion packs
  • Voltage: Excellent match for gear requiring 12V – 13.8 VDC
  • Longevity: Excellent. Thousands of charge/discharge cycles
  • Ease of recharging: Simple, using the provided charger (battery packs have a built-in charge controller)
  • Solar charging option: Bioenno sells charge controllers designed to work with LiFePo batteries, handy for the field

Without a doubt, the best-known LiFePo battery manufacturer in the world of ham radio is Bioenno Power. I’ve purchased their batteries exclusively and have been incredibly pleased with the quality, longevity, and performance of their products.

Choosing the right battery for you

Each one of these battery types have their pros and cons, and you can find lengthy, in-depth discussions online about the nuances of each battery chemistry. At the end of the day, however, what matters is which one best suits your particular application and provides your gear with the appropriate amount of voltage.

Here’s when I would reach for each of our types of batteries…

NiMH LSD AA batteries

WD8RIF uses Eneloop rechargeable AA batteries with his Elecraft KX3 field kit (Photo: WD8RIF)

If you’re willing to use a battery pack to run 8-12 cells in series to achieve your required nominal output voltage, Eneloop batteries are relatively affordable, lightweight, and of course, power an array of electronic devices in our world.

If you plan to use QRP power for short periods of time, these may suit your needs quite well. My buddy and Elmer, Eric (WD8RIF), has used Eneloop batteries to power his Elecraft KX3 for the majority of his Parks On The Air activations.

Of course, AA Eneloop batteries are also invaluable for those of us who have an arsenal of portable shortwave radios that accept AA cells!

Sealed Lead Acid Batteries

If you’re on a very tight budget and weight is less of a concern, SLA batteries are a great choice. They’re an especially affordable option if you plan to make a solar-powered battery pack since charge controllers are quite simple and affordable.

If you’re looking for a stationary back-up battery for home, these are an excellent choice, as long as you keep the charge topped up.

Li-ion Batteries

Backpacking or flying overseas, and size and weight really do matter? Purchase a Li-ion battery system. Li-ion cells and packs offer the highest energy density of any of the battery chemistries in this list. They’re incredibly compact––and as long as you use a quality charge controller with built-in protections, and you don’t damage or puncture an actual Li-ion pack––they should be quite safe, and you’ll be pleased with performance. Note:  Keep in mind some airlines have regulations about the size of Li-ion battery pack you’ll be allowed to carry on board, so do check before departure.

LiFePo Batteries

The 9V 3Ah Bioenno LiFEPo4 pack is very compact and pairs beautifully with the Mountain Topper MTR-3B as this particular transceiver prefers voltages at 12 volts and below.

If you’re looking for a simple, effective portable battery solution that is almost custom-designed to power radio gear, invest in a LiFePo4 battery and charger. I have everything from a 15 Ah 12V LiFePo4 battery that can power my 50 watt Mission RGO One transceiver, to a 3 Ah 12V pack I now use for 2-3 hours in the field at a time with my QRP transceivers. Bioenno has recently sent me a 9 V 3 Ah battery pack to test with my Mountain Topper MTR-3B––it’s incredibly compact, since it only needs three 3.2V cells in series. LiFePo batteries are also the ones I suggest for those who are new to the world of battery packs and want something that is hassle-free and simply performs.

 

I admit, I’m being transparent here about why I own a total of three LiFePo4 batteries from Bioenno Energy––they’re amazing and I know I can rely on them.

In summary…

…I would offer this final piece of battery-usage advice: whatever you do, don’t “cheap out” on your battery and charging system. No matter what chemistry you decide to purchase, buy the best quality you can afford. If using any variant of a Li-ion battery, heed my tale, and be sure any separate charge controllers you employ will protect your battery (and your home)!

And now…Go out there and have fun. I assure you:  when you take your radios––whether portable shortwave radios or ham radio transceivers––to the field, you’ll find you can escape all of the noises that so often plague us indoors. And out there, you, too, may find your radio bliss.

Guest Review: CW Morse Single-Lever Keyer Paddle

On October 10, I took delivery of a CW Morse (https://cwmorse.us/) “Red Single Paddle Morse Code Key With Base” (https://cwmorse.us/product/red-single-paddle-morse-code-key-with-base/) which Tom Witherspoon, K4SWL, had sent me to review for this website. CW Morse had sent Tom several keys to review and Tom, knowing I am a fan of single-lever paddles, sent me the CW Morse single-lever paddle to review.

CW Morse "Red Single Paddle Morse Code Key With Base"

CW Morse "Red Single Paddle Morse Code Key With Base", inside view

I will admit it: I wasn’t expecting much from a 3-D printed CW paddle, but I was very surprised by the quality of the build and the feel of the paddle.

The “Red Single Paddle Morse Code Key With Base” is a nice mix of 3-D printed frame, lever, fingerpiece, and cover with steel ball bearings, metal contacts, steel centering springs, and a heavy steel base. (See photos, above.)

The mailman delivered the paddle on October 10  and I started using it almost immediately as a cootie-key / sideswiper to hunt Parks on the Air (POTA) activations. (A cootie-key or sideswiper is a manual key in which the operator moves a paddle alternately side-to-side to manually create the dots and dashes of Morse Code.) The paddle worked very well as a cootie and I made six POTA QSOs using the paddle on the afternoon of the 10th. Unfortunately, when I tried to use the paddle for my nightly ragchew-QSO with K8RAT, the paddle stopped centering properly and I had to switch to another key to finish the QSO. A day or two later, I studied the CW Morse key and found that I was able to loosen the nut at the lever pivot-point a little bit to reduce drag. After this simple adjustment, the paddle has worked beautifully without further need for adjustment.

The “Red Single Paddle Morse Code Key With Base” features adjustable gaps on both sides of the lever. These gaps are easily adjusted using the supplied Allen wrench or with bare fingers. The spring tension is not adjustable and the paddle’s feel is pretty light.

The steel base, while small, is quite heavy and the four rubber feet provide excellent traction on my radio desk. I have a pretty heavy fist and this paddle is almost heavy enough that I can send with my right hand without holding the paddle with my left hand.

Now, a disclosure: I have been using semi-automatic bugs and fully-manual cootie keys so long now that my keyer fist is absolute rubbish. I did use the paddle to drive an electronic keyer for one ragchew-QSO and the paddle worked very well in that mode and it had a nice feel–any mistakes made in keying were not the fault of the paddle but of my own inability anymore to judge how long to hold the dash-paddle.

I’ve been using this paddle as my go-to cootie-key for over half a month now and as a cootie key the “Red Single Paddle Morse Code Key With Base” excels. The gaps were easily adjustable and the feel of the paddle as a cootie is just fantastic. This key has, at least for the moment, become my favorite hamshack cootie-key.

The “Red Single Paddle Morse Code Key” can be removed from the steel base for field or portable use and I did remove the key from the base to try it in this configuration. Unfortunately, I didn’t like the feel of the paddle in my left hand, primarily because the two mounting rails make the key feel awkward in my hand. CW Morse does offer a dual-lever field paddle (https://cwmorse.us/product/pocket-double-paddle-morse-code-key/) and I think a similar design with a single lever would make an excellent field paddle or cootie key. (Read about Tom Witherspoon’s experience with the dual-lever field paddle here: https://qrper.com/2020/10/pota-field-report-pairing-the-icom-ic-705-with-the-elecraft-t1-and-cw-morse-pocket-paddles/.)

Bottom Line: I have been very pleased with the “Red Single Paddle Morse Code Key With Base” and I can recommend it for any CW operator who needs an inexpensive but well-made single-lever paddle.

Eric’s DIY Cootie: “Levon”

Many thanks to Eric (WD8RIF) who writes:

Well, if K8RAT is going to tout Hermione, I guess I need to tout Levon.

My cootie/sideswiper was inspired by an article (http://sideswipernet.org/articles/w9ok-modernization.php) by W9LA about how hams in the 1930s might have constructed a cootie/sideswiper using a ceramic DPST knife switch. I didn’t have a ceramic DPST knife switch, but I did have a nice Leviton ceramic DPDT knife switch which I used as the basis for my cootie/sideswiper. Instead of using tape for the fingerpieces as described in the article, I used Fender guitar picks.

This cootie is the key I use most often for home-based operations.

While operating in the field, I usually use an inexpensive and lightweight Whiterook MK-33 single-lever paddle as a cootie key.

Levon is a handsome sideswiper, Eric! Thanks for sharing his story and your photo!

Thanks to both of you, I feel inspired to make my own “cootie” this winter. Perhaps I’ll try to find some historic context/inspiration as well!

Any other homebrew sideswipers, straight keys, or paddles you’d like to share? Please contact me and we’ll feature your creations!

I’ve got a very special one that’ll be featured later this week. Stay tuned!

A Photographic Tour of Universal Radio’s New Location

In October, 2017, Universal Radio moved from their large Reynoldsburg, Ohio retail store and warehouse to a smaller retail store and warehouse at 651-B Lakeview Plaza, Worthington, Ohio. This is actually Universal Radio’s fourth location in its 75 year history. In 1942, Universal Service opened on North Third Street in downtown Columbus. In 1977, Universal Radio moved to Aida Drive in Reynoldsbutg. In 1992, Universal Radio moved to Americana Drive in Reynoldsburg. Finally, in 2017, Universal Radio moved to the current location in Worthington.

On Friday, November 17, I had the opportunity to visit the new location of Universal Radio  for the first time and I prepared a photographic tour of the new location.

The new location is smaller than the previous location and instead of consisting of one large showroom space, the new location consists of several smaller rooms. (Indeed, the new layout reminds me the layout of one of my all-time favorite bookstores, the Book Loft in Columbus’s German Village neighborhood, which now has 32 (!) rooms of books. No, Universal Radio’s new store does not have 32 rooms!) As can be seen in the following photographs, these rooms are densely stocked. Universal Radio still offers all the items that were available in the previous store location. Of course, just as at the previous, larger, location, some items aren’t on immediate display but are available upon request.

The new Universal Radio storefront at 651-B Lakeview Plaza Blvd, Worthington, Ohio
The new Universal Radio storefront at 651-B Lakeview Plaza Blvd, Worthington, Ohio. There’s more than ample parking.
The sign and entrance to the new Universal Radio store
The sign and entrance to the new Universal Radio store.
Books, with Barb stocking the shelves with the newest "The Worldwide Listening Guide"
Immediately upon entering the store, one will find hundreds of book titles. Here, Barb is stocking the shelves with the newest, just-released, “The Worldwide Listening Guide”.
Magazines
And, of course, Universal still offers several issues each of the two major American amateur radio magazines.
Antennas, shortwave receivers, HTs, scanners + VHF/UHF mobiles
In the main showroom: antennas, shortwave receivers, HTs, scanners, and VHF/UHF mobile transceivers.
HF transceivers
In the same showroom, the HF transceivers, available to operate.
The Heil microphone display
The Heil microphone and headset display.
Used equipment
The Used equipment display: HF transceivers, shortwave receivers, VHF/UHF transceivers, handhelds, and accessories.
Antennas!
Antennas!
More antennas!
And more antennas!
The warehouse area, with Barb and Cathy
Just as with nearly any other modern retailer, Universal Radio’s bread-and-butter is internet and telephone orders. This is just a small portion of the new warehouse and shipping area, with Barb and Cathy busily filling orders.
The warehouse area
A small portion of the warehouse and shipping area.
The well-equipped service area
Universal Radio still has a nicely-equipped service area.

Just as at the previous Reynoldsburg location (and at the even earlier Aida Drive location), the new Universal Radio store is home to several cats which, sadly, I neglected to photograph.

The new store is staffed by the same friendly and helpful people we’ve come to know from the Americana Drive location. During this visit, I saw and spoke with Josh, Eric, Barb, and Cathy.

National Parks On The Air (NPOTA) activations today

IMG_20160519_105823050_HDR

En route to the 2016 Dayton Hamvention, I’m doing a few National Parks On The Air (NPOTA) activations with my my buddy, Eric (WD8RIF).

Eric is currently the number one activator in the state of Ohio.

NPOTA is a great excuse to get outdoors and play radio.

For me, it’s a great excuse to test the LNR Precision LD-11 and my new QRP Ranger portable power pack.

IMG_20160519_101759179

I am loving the new QRP Ranger power pack–it is the solution I decided on after publishing this post a few weeks ago. It’s a little pricey, but it’s built like a tank, very lightweight, includes a charge controller made specifically for the LiFePo cells, and made here in the USA. It also had a very readable LED display that my buddy Eric says is, “reminiscent of the displays on the Apollo 11 module.” He’s kind of right!

It’s so nice to have both a volmeter and ammeter on the front panel.

IMG_20160519_111039495

 

We just finished activating the Hopewell Culture National Historical Park (I’m writing this post while Eric drives us to our next activation). I made 12 contacts running SSB at 8 watts. Eric made 16 contacts via CW at 5 watts.

We have planned two more activations this afternoon:

  • Charles Young Buffalo Soldiers National Monument at 16:30 UTC
  • Dayton Aviation Herital National Historical Park at 21:00 UTC

I’ll be calling CQ on 14.290 MHz and 7.290 MHz +/-.

Please hop on the air listen and/or answer my call if you’re a ham!

Of course, tomorrow through Sunday, you can find us at the Dayton Hamvention in booth SA0359 in the Silver Arena.

Hope to see you there!

A KX3 Build

Elecraft KX3
Elecraft KX3 by WD8RIF

I recently built an Elecraft KX3 kit and took photographs of the process as I went along. Your host of QRPer.com, K4SWL, thought others would benefit from seeing how simple the process of building a KX3 really is. My thoughts and the photos of the process can be seen here on my website:

http://home.frognet.net/~mcfadden/wd8rif/kx3.htm

An External Battery for the KX1

NOTE: I am embarrassed to admit that I made a significant error in my original measurement methodology and the numbers originally listed below were inaccurate. I’ve redone all the measurements and the text and tables below reflect the corrected measurements. *

Your host, K4SWL, asked me to share my experiences in trying to find a small, lightweight, battery pack for use with my field-portable QRP station. While I’m looking for a battery pack specifically for my Elecraft KX1, what I’m learning should be useful for users of any low-current QRP transceiver.

original 10-cell battery-holder -- click to enlargeCurrently, I’m experimenting with a pair of ten-cell AA battery-holders, one of unknown provenance (photo) and a new, more rugged one from Batteries America (p/n 10AAT, photo). When filled with ten AA NiMH cells, the resulting battery-packs provide about 14v at full-charge. At the 2012 Flight of the Bumblebees, my KX1 generated an indicated 2.6w on 20m and 4w on 40m while being powered by one of these packs; the nearly four hours of low-stress operating during this event did not discharge this pack of 2,000mAh cells very deeply. The use of two AA dummy-cells will also allow the use of eight lithium primary or alkaline cells in an emergency.

new 10-cell battery-holder -- click to enlargeI became concerned about using this style of spring-contact battery-holder when I found an article (link) by Phil Salas, AD5X, in which he reported that this sort of battery-holder is likely to display significant voltage drop under load.

I tested my original battery-holder with ten 2,000mAh NiMH cells and my KX1 transmitting into a dummy load. In addition to measuring whole-pack voltage-drop, I measured the voltage-drop of each of the individual 2,000mAh cells as I transmitted into the dummy load on 20m.

Original Battery-Holder / 2,000mAh cells
Band ΔVpack ΣΔVindiv.
20m 0.76v 0.52v
30m 0.79v
40m 0.75v
80m 0.70v

The sum of these individual drops was 0.52v, so I’m losing 0.24v in the spring-contacts and/or battery-holder’s “transistor battery” output connector.

After replacing the original nylon connector with a pair of Anderson Powerpoles, I tested the same 2,000mAh NiMH cells in the new, more rugged battery-holder, this time only on 20m:

New Battery-Holder / 2,000mAh cells
Band ΔVpack ΣΔVindiv.
20m 0.73v 0.53v

I’m losing about 0.20v in the battery-holder’s spring-terminals, slightly less than with the older battery-holder.

The 0.20v ~ 0.24v drop from the spring-terminals doesn’t seem excessive to me and the difference in these measurements between the two battery-holders is probably not significant. I am more concerned by the 0.53v ~ 0.54v voltage-drop I measured in the individual cells. It is likely that these older 2,000mAh cells, which have been cycled many times, are exhibiting greater voltage-drop than new cells would. To test this theory, I purchased new 2,100mAh cells to measure.

I measured the new cells as above, again on 20m into a dummy load, and found that with each of the battery-holders, the sum of the individual cell voltage-drops was 0.22v, so my speculation appears to have been correct–the new cells do have lower voltage drop under load than the old cells do.

Orignal Battery-Holder, 2,100mAh cells
Band ΔVpack ΣΔVindiv.
20m 0.48v 0.22v
New Battery-Holder, 2,100mAh cells
Band ΔVpack ΣΔVindiv.
20m 0.47v 0.22v

The new 2,100mAh NiMH cells are marketed by Polaroid and cost $6 per four-pack at Big Lots; the least expensive AA NiMH cells available at Batteries America, 2,500mAh Sanyo cells, cost $3 each at the time of this experiment. I don’t know if the Polaroid cells will last for as many cycles as the probably-higher-quality Sanyo cells would but trying the significantly less expensive Polaroid cells seemed like a a good gamble.

As indicated above, the new battery-holder (Battery American p/n 10AAT) is more rugged than my original battery-holder; it holds the AA cells more securely and and doesn’t use a “transistor battery” connector to connect to the load. I replaced the original nylon connector with a pair of Anderson Powerpoles. This battery-holder will be my preferred battery-holder for field operations with the KX1.

In his article (link), Phil Salas, AD5X, recommends foregoing battery-holders in favor of soldered/welded battery packs but I will continue to experiment with battery-holders. I prefer to charge my NiMH cells individually, using an intelligent MAHA charger, rather than charging an entire pack. In addition, my KX1 draws significantly less current on transmit than Phil’s IC-703 does so the the IxR losses I’ll experience will be less significant than that which Phil experienced.

Visit my website to learn more about my QRP operations or to learn more about my KX1 Mini Travel Kit.

* What had I done wrong? I discovered when testing my new battery-holder that the previous measurements of the old and new NiMH cells in the original battery-holder had been made with the KX1 transmitting into a 50Ω dummy load with the KX1 autotuner configured in tune mode instead of in bypass mode; because the KXAT1 autotuner doesn’t sense a mismatch and automatically tune, this meant that transmitter current–and the measured IxR voltage losses–might be also be significantly different than with the KX1 transmitting into a matched load. Comparisons of my original numbers to measurements made later of the new battery-holder wouldn’t be meaningful, so I had to do all the measurements again.