Many thanks to Steve (KV4AN), who shares the following article about his portable field radio kit, which will be featured on our Field Kit Gallery page.  If you would like to share your field kit with the QRPer community, read this post.

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KV4AN’s MTR3B-V4 Field Kit

by Steve (KV4AN)

The convergence of Solar Cycle 25, lots of great new equipment offerings, many active participants in Parks on the Air (POTA), Summits on the Air (SOTA), and compatible family outdoor activities make this a great time to be a portable High Frequency (HF) QRP ham radio operator.  To take advantage of this happy situation, I was recently able to purchase a MTR3B-V4 “Currahee” Mountain Topper transceiver, shown in figure (1).  The MTR3B-V4 is a miniature three band (40, 20, and 15 meters) CW only QRP transceiver made by LNR Precision.

Naturally, I had to form a kit around the new radio.  My three goals for the kit were: small size, lightweight, and self-contained.  Let’s see how I did.  You can comment below if I left something out or if there’s a better choice.

The kit consists of the following items, as shown in figure (2)–links to these items are at the bottom of the page:

1. MTR3B-V4 “Currahee” Transceiver – 40, 20, and 15 meter QRP CW Transceiver.
2. Custom Faceplate Cover – A practical and reasonably priced custom faceplate protective cover.   I accidentally ordered the cover for the previous version of the radio, but Joshua had no problem with me changing the order to the new one.
3. Morse Code paddle – This is a reasonably priced paddle with a fairly good feel that I had lying around when the capacitive knobs didn’t work out.  I plan to replace it in the future with the CW Morse SP4 POTA/SOTA N0SA design paddle, which is smaller and field proven.
4. 3.5mm Stereo Cable – A 1.5 foot, 3.5mm to 3.5mm stereo (TRS) cable.
5. Koss Earbuds – Nice quality stereo earbuds.
6. Earbud Cord Organizer – I hated to add the extra item, but I got tired of untangling the  wires of my earbuds.  This clever item has solved that problem and is color coordinated with the slick line.
7. All-Weather Notebook – All-weather notepad for copying QSO information in the field.
8. Miniature Pen – This is a miniature pen that says it writes on waterproof paper.  It will also write upside down, although that may not be a feature you need during normal activations.
9. Koss In-line Volume Control – An in-line volume control for use with the earbuds.  The MTR3B-V4 has a rudimentary volume control, primarily used to set the maximum volume level.
10. Battery Pack Pouch – A small pouch that perfectly holds the battery pack and keeps all the components together and protected.  If you use Icom BP-307 or BP-272 battery packs, they fit perfectly too.
11. Battery Cell Holder – An eight “AA” cell holder with a 9V-style clip.  Eight “AA” NiMH batteries will provide a nominal 9.6V to the transceiver.
12. AA NiMH batteries – Eight 1.2V “AA” NiMH 2800 mAh Low Self Discharge (LSD) battery cells.
13. 9V Snap Clip – These are good quality 9V snap connectors that also have the coaxial power connector required by the MTR3B-V4 already attached.  They are more durable than the ones with exposed thin red and black wires.
14. Coaxial Adapter – SO-239 to BNC adapter for use when using other antennas with coaxial cables which have a PL-259 connector.
15. Reliance EFHW “Bugout” Antenna – A very small and sturdy 40, 20, 15, and 10 meter End-Fed Half Wave (EFHW) resonant antenna.
16. Slick Line – High visibility slick line, which ties to the arborist throw bag to get the antenna into a tree and then suspends it.
17. Arborist Throw Bag – A well-made arborist throw bag with a good all-around weight.
18. Gerber Mullet Keychain – An all-in-one minimalist tool kit.  Better than a sharp rock, as they say.
19. Rothco Shoulder Bag – A military-style shoulder bag, just large enough to hold all the kit components.
20. Battery Charger – The battery charger (not shown) is an eight cell NiMH charger.  It does not fit in the shoulder bag and is left at home.

Of course, it all had to fit in a tacticool bag.  I selected the small Rothco Excursion Organizer, The shoulder bag, shown in figure (3), has all the items from figure (2) in it (trust me).  Use the orange pen as a reference for the size of the bag.  Clipped to the “D” ring on the left side is the Gerber “tool kit”.  The pocket on the front left has the CW Morse paddle, the pen is in its place, and the zippered pocket on the right has the earbuds.  The back zippered pocket has the antenna and battery pack, and safely nestled in the main area is the MTR3B-V4 and an arborist throw bag.  There is a zippered sleeve in the main pocket that contains the cable for the keyer paddle, an adjustment Allen wrench, and the SO-239 to BNC adapter.

Conclusion

One thing you may have asked yourself is why I included a Morse Code paddle when the MTR3B-V4 has a set of capacitive touch knobs.  The answer is simple – they didn’t work for me.  I really wanted them to, but the pad of my thumb will not activate the “dit paddle” without moistening it first.  Even then, I have to press the knob hard at a point almost to the joint, which is not a natural code sending motion or feel and results in very sloppy code.

Another item I purchased, but decided not to use was a pair 9V 500 mAh Lithium Ion rechargeable batteries.  The voltage of this battery right off the charger is below the specified input voltage for the MTR3B-V4.

The battery is the area in which I am most concerned.  I’m concerned that the 9.6V NiMH pack may not provide enough voltage over an activation to keep the voltage above the specified minimum voltage of 9V.  I may have to go to a 12V LiFePO4 battery, but that will not fit in the current shoulder bag.  I may have to go with a larger bag or use a MOLLE system where I can strap together several pouches.

I think I’ve came close to achieving my three goals of: small size, lightweight, and self-contained.  I’ve not completed an activation with this kit yet, so I’ll see how it all works together in a few weeks.  I’m also looking forward to reading your comments and suggestions.

72,

Steve

KV4AN

Gear List Links

[Note: Most Amazon and CW Morse links are affiliate links that support QRPer.com at no cost to you.]

1. MTR3B-V4 “Currahee” Transceiver (MTR3B V4 Currahee Mountain Topper)
2. Custom Faceplate Cover (LNR MTR-3B-v4 Currahee Magnetic Protective Cover – Tufteln)
3. Morse Code paddle (Black Pocket Double Paddle Morse Code Key – cwmorse.us)
4. 3.5mm Stereo Cable (Amazon.com: Aux Cord 1.5ft, 3.5mm Aux Cable – Nylon Braided Audio Cable 3.5mm Male to Male AUX Cord Compatible with Car,Headphones, iPods, iPhones, iPads,Tablets,Laptops,Android Smart Phones& More (1.5FT) : Electronics)
5. Koss Stereo Earbuds (Amazon.com: Koss 191651 KE5 Earbuds (Black) : Electronics)
6. Earbud Cord Organizer (Amazon.com: ELFRhino Cord Organizer Earbuds Holder Earphone Wrap Earphones Organizer Headset Headphone Earphone Wrap Winder Cord Manager Cable Winder Green : Electronics)
7. All-Weather Notebook (Amazon.com : GLORYFIRE Waterproof Notebook Tactical All-Weather Spiral Memo Paper Notepad with Waterproof Grid Paper for Outdoor Activities Recording 3″x5″ (5pcs) : Office Products)
8. Miniature Pen (Amazon.com : Tombow BC-AP54 Pressurized Permanent Ballpoint Pen (Can Write on Wet Paper/Back), Air Press to Squeeze Ink Ink, 0.7, Orange : Rollerball Pens : Office Products)
9. Koss In-line Volume Control (Amazon.com: Koss 155954 VC20 Volume Control, Standard Packaging, 39-Inch Cord, Compatible with Cell Phones and Headphones : Volume Control: Electronics)
10. Battery Pack Pouch (Amazon.com : TRIWONDER Tactical Cigarette Pouch Molle Small Military Bag Battery Cigarette Case EDC Utility Card Holder Lighter Slot Mini Cigar Waist Pack (01 Green – 2 Pack) : Sports & Outdoors)
11. Battery Cell Holder (Amazon.com: QTEATAK 2Set 8 x AA Thicken Battery Holder with I Type Wired Battery Clip Standard Snap Connector : Electronics)
12. AA NiMH Batteries (Amazon.com: WENJOOP Rechargeable AA Batteries, 2800mAh High-Capacity NiMH AA Rechargeable Battery Long-Lasting Power, 8 Pack Double A Batteries Size for Household and Office Devices – 1.2 Volt Low Self Discharge : Health & Household)
13. 9V Snap Clip (Amazon.com: CHANZON UL Wire 9V Battery I-Type Power Supply with Center Positive 2.1mm x 5.5mm Male DC Connector Holder Clip Converter, 5 Pack for Arduino, LED Strip : Electronics)
14. Coaxial Adapter (Amazon.com: Ahoaepy 2PCS UHF to BNC Adapter, Low Loss SO239 Female to BNC Male Coaxial Cable Connector Adapter for CB Radio,Radio,Antennas.Extension Coax Cable : Electronics)
15. Reliance EFHW Antenna (EFHW Bugout 56:1 40-10M Antenna – Reliance Antennas)
16. Slick Line (Amazon.com : LiteOutdoors Guyline & Tensioner Kit – 1.8mm Diameter – 60 or 100 feet – Ultralight Reflective Tent Cord, Lightweight Non-Slip Cord Adjusters. Camping, Hiking, Paracord : Sports & Outdoors)
17. Arborist Throw Bag (Amazon.com : SOB Outdoor Throw Weight Bag 250g Arborist Durable Climbing Rope Bag Multi Throw Bag Tree Rock Spelunking : Sports & Outdoors)
18. Gerber Mullet Keychain (Gerber Gear Mullet Keychain – Multi-Tool Keychain with Pry Bar, Bottle Opener, and Wire Stripper – EDC Gear and Equipment – Stonewash – Amazon.com)
19. Rothco Shoulder Bag (Amazon.com: Rothco Excursion Organizer Shoulder Bag, Olive Drab : Clothing, Shoes & Jewelry)
20. Battery Charger (Amazon.com: EBL AA AAA Battery Charger, 8-Bay Individual Charger for NiMH NiCD Rechargeable Batteries with AC Plug Fast Charging : Electronics)