The Enhanced KX3 Travel Kit is a small but complete low-power HF+6m station in a small, weather-resistant LowePro Traveler 150 photography backpack. The Enhanced KX3 Travel Kit is an enhancement of the original KX3 Travel Kit and is designed for rapid deployment following transport by foot or motorized transport.
The Enhanced KX3 Travel Kit is under continuous development. Photos may not represent the current state of the station. This page will change as various ideas are tested and accepted or rejected.
The heart of the Enhanced KX3 Travel Kit is an Elecraft KX3 low-power transceiver equipped with the KXAT3 Internal Automatic Antenna Tuner module, the KXFL3 Dual-Passband Roofing Filter module, AK6Q Side KX Endplates, and VE7FMN Cooler KX Lite heatsink.
The trail-friendly KX3's all-band (160-6m) coverage, all-mode (CW/SSB/AM/FM/data) capability, competition-grade receiver, truly generous feature-mix, small size, low weight, and battery-friendly design make the KX3 an extraordinary field-radio.
The KX3 can operate over a voltage range of 8vdc to 15vdc. Internally, the KX3 can accomodate eight AA cells. A coaxial power socket is provided for connection to an external power source. When internal batteries are installed and external power is connected, the rig will use the source having the higher voltage.Internal Batteries
The KX3 internal battery holders accomodate eight AA cells. When filled with 1.2v NiMH cells, this produces a nominal 9.6-volt battery-pack. Because of reports from W8MHV of poor battery life when powering his KX3 with internal NiMH cells1, at this point in time I have decided against keeping NiMH cells in the KX3 or purchasing the KXBC3 Internal NiMH Charger / Real-Time Clock module.
It's possible I might decide to keep a set of lithium primary cells (1.5v, 2.8 - 2.9Ah) installed in the KX3 in case of an emergency. If so, I might choose to install just seven cells and use a dummy cell in the eighth position to ensure that an external power source (see below) always measures higher in voltage than the internal battery.
For most operations with my KX3, I will rely on an external battery.
For short-duration field operations, I have a rugged ten AA-cell holder (Batteries America p/n 10AAT, photo | link) I can fill with ten 1.2v NiMH cells or, in a pinch, eight alkaline cells (1.5v, 2.2 - 2.7Ah) or lithium primary cells (1.5v, 2.8 - 2.9Ah) plus two dummy cells. Either way it's configured, this pack is a nominal 12-volt pack. I am currently using a set of ten Sanyo Eneloop 2000mAh NiMH cells with this battery-holder. (See KX1 Mini Travel Kit for a discussion on spring-type AA-cell holders.)
For long-duration field operations, I use an existing 2.2Ah or 5Ah 12v gel-cell that can be float-charged by a photovoltaic panel while in use (see below). Either one of these batteries fit nicely within the Traveler 150.
I would love to try a Lithium Iron (LiFePO4) battery pack for field operations with the KX3. The 13.2vdc 4S1P (2.5Ah) or 4S2P (5Ah) LiFePO4 packs by A123 (link) have very high power density and are much lighter than comparably-rated SLA batteries, but the A123 battery packs are also significantly more expensive than NiMH or gel-cell batteries of similar capacity and require a special charger. The 10Ah and 7Ah "LiFePO4 Upgrade" batteries offered by Dakota Lithium Batteries (link) are each the same size as a 7Ah SLA but weigh about half as much as the SLA, can be charged with existing SLA chargers or a constant-voltage current-limited 14vdc source, and cost considerably less than the batteries by A123.
I have a pair of Powerfilm (link) FM15-300 5-watt foldable photovoltaic panels (photos: 1 | 2) which I use with a WB8VGE Micro-M charge controller (photo | link, ARRL Members Only) to charge the above-mentioned 2.2Ah or 5Ah gel-cell batteries. One of these panels plus the associated cables fit nicely in an outside pocket of the Traveler 150. (These FM15-300 panels are "blems/seconds" I purchased at a greatly discounted price directly from PowerFilm at the 2012 and 2014 Dayton Hamventions.)
I also have a pair of glass-and-aluminum 5-watt photovoltaic panels. One of the panels is an inexpensive but relatively large (~ 12"x18") thin-film panel (photo) I purchased new at Harbor Freight. The second panel, an old Hoxan SP 5, is a polycrystalline panel (photo) and is much smaller (~ 9"x10"). I purchased this panel used at a hamfest but it still provides rated voltage and current. Either of these glass-and-aluminum panels would be the better choice for long-term operations or for operation when rain or severe weather is expected because Powerfilm recommends my foldable panels not be used while wet. (It is my understanding that newer Powerfilm foldable panels can be allowed to get wet.) Unfortunately, neither of the glass-and-aluminum panels can be carried within the Traveler 150.
The Micro-M charge controller is configured to work with any of my photovoltaic panels and to allow me to charge a gel-cell battery while the battery is simultaneously powering the rig.
I would like to find a way to charge my ten AA-cell NiMH battery-pack using one of my solar panels. NiMH cells, it turns out, aren't as easy to charge as lead-acid or NiCD cells. Note to self: Powerstream offers instructions on charging NiMH cells (link) and sells a charge-controller for 8-, 9-, or 10-cell NiMH packs (link).
1 The KX3's power-output control doesn't directly set the transmitter output power. Rather, it tells the radio what power-output the operator wants and the radio makes sure that output-power is generated. Since P=IxE, lower supply voltage (E) means more current (I) must be drawn to produce a desired power (P).
The KX3 covers all bands 160m through 6m. It would be very challenging (or, more likely, impossible) to find a single easy-to-deploy field antenna that works well on all of these bands. Fortunately, I am primarily interested in operating on the bands 80m through 10m while in the field, making the task of finding a single field-deployable antenna that's small enough to pack easily much more manageable.
Currently, for 10m-40m, I carry a 28½' end-fed wire and three 17' counterpoise wires which I connect to the KX3 through a BNC-to-dual-banana-socket adapter. This antenna served me well throughout my National Parks on the Air activations in 2016 although there were a few rare situations in which the KX3/KXAT3 wouldn't tune the antenna on one band.
For 80m, I've tested a 58' (source) end-fed wire. The low-hanging 58' wire tuned well on 80m only when the (then) 28' wire and two of shorter wires were connected as a counterpoise. This antenna was connected to the KX3 using a BNC-to-dual-banana-socket adapter. (Note to self: N7RR reports that a 58' radiator with one 13.1' counterpoise loads on all bands 80m-6m on his KX3 with KXAT.)
For 10m-80m, I've tested a 42' W3EDP Jr. antenna (link). During my initial test, with the antenna connected through a 4:1 balun, my KXAT3 found a good match for all bands 10m-40m but didn't find a match on 80m.
I plan to experiment with replacing the BNC-to-dual-banana-socket adapter and the 4:1 balun with a 4:1 unun (links: 1 | 2). I'm hopeful that the unun will improve the performance of the 28½' end-fed wire and allow the W3EDP Jr. to be used on 80m.
To hang wire antennas in trees, I carry a length (~66') of very small parachute cord in a camping-style clothesline reel; I typically spool the line fully out of the reel, tie the free end to a half-full disposable water-bottle, and lob the bottle over a tree-branch or, if the tree is small, over the whole tree. I also carry a 100-yard spool of dental floss and a couple of large fishing weights to use in a similar fashion. Note to self: Consider painting the fishing weights highway-safety orange.
For my 2016 National Parks on the Air activations, I carried an MFJ-1910 33' fiberglass telescoping mast, a re-purposed roof-top tripod, stakes, and a hammer in a canvas military-surplus antenna-bag. I quickly found that erecting this mast assembly to support the 28½' end-fed wire is usually quicker and easier than throwing a line over a branch—and it works when there isn't a tree or branch available. This mast isn't tall enough to support the entire W3EDP Jr. as a vertical but can support it in an L, inverted-L or inverted-V configuration.
Descriptions of field-deployable antennas I've used with the larger K2 Travel Kit are located here. Any of the antennas that worked well with the K2 Travel Kit should work well with the smaller Enhanced KX3 Travel Kit but may need to be carried externally.
The KX3 has a perfectly adequate built-in memory keyer so I don't need to carry an external memory keyer with the Enhanced KX3 Travel Kit.
Having given up on dual-lever keyer paddles, I chose not to purchase the otherwise excellent Elecraft KXPD3 Precision Iambic Keyer Paddle for use with my KX3.
I have purchased the AME The Porta-Paddle Leg Mount (link) for use with the Mini-B but have not tried it in the field. The Leg Mount fits nicely in an outside pocket of the Traveler 150.
UPDATE: During the 2016 National Parks on the Air year-long event, the Mini-B got intermittent, as if the contacts were dirty. Cleaning with DeOxit and light burnishing restored performance for a while but the problem kept returning. I finished NPOTA using my Whiterook MK-33 Mini Single Lever Paddle (photo | link).
I would dearly love to have the gorgeous Begali Adventure Mono paddle (link) to use with my KX3 but at a price of €258 for the key plus €28 for the KX3 mounting bracket, I am unlikely to be able to purchase one anytime soon.
I've come to realize that when wearing gloves, as I almost certainly will be doing during the annual "Freeze Your B___ Off" events, a straight key would allow me to send better CW than would a small keyer paddle. In this situation, I will use my lightweight Whiterook MK-22 Pocket Mini CW Key (photo | link).
NOTE: Elecraft transceivers require a three-conductor (stereo) jack for the CW key connection. As purchased, the Whiterook MK-22 requires a two-conductor (mono) jack. I've modified my MK-22 to use a standard stereo audio cable so I can more easily use it with my KX3.
My primary microphone for voice modes (SSB/AM/FM) with the KX3 is an Elecraft MH3 Hand Microphone. I have received reports of excellent audio quality when I've used this microphone during SSB and AM QSOs. I seldom use voice-modes on HF so this microphone won't usually be part of the Enhanced KX3 Travel Kit.
Using Acrobat Reader X and an available duplex color printer, I printed the KX3 Owner's Manual in half-size "booklet" form. This booklet, log sheets, and paper for CW copy are carried in the Traveler 150's front pocket.
The KX3 has a small built-in speaker but I prefer to copy CW through stereo headphones, particularly since the KX3 provides very useful simulated stereo audio effects for CW reception. I carry an inexpensive pair of stereo headphones in the Enhanced KX3 Travel Kit.
For some field operations, I've been carrying a home-made custom clipboard to allow easy CW sending, CW copying, and logging (photo). The clipboard is larger than a usual clipboard and features a spot of 3M Dual Lock material for securing the AME Mini-B CW paddle. This clipboard does not fit within the Traveler 150, of course.
I built the Enhanced KX3 Travel Kit to encourage me to engage in impromptu field operations via foot or motorized-vehicle.Hiking
I hiked with the Enhanced KX3 Travel Kit up to Lookout Point in Athens, Ohio, for the QRP Afield 2015. The station carried well and performed well.
During 2016, I optimized the Enhanced KX3 Travel Kit for ARRL National Parks on the Air (link) activations. One optimization was to also carry an MFJ-1910 33' telescoping fiberglass mast, a tripod, stakes, and hammer in military-surplus antenna-duffle. The mast was used to very quickly support the 28' end-fed wire antenna when a suitable tree wasn't available.
I have found the Enhanced KX3 Travel Kit to be easier to carry in an automobile or other motorized transport than the original KX3 Travel Kit was. The original KX3 Travel Kit was so small that for anything other than a minimal operation I almost always had to carry a box or bag of other things—a gel-cell battery, a solar panel and charge-controller, maybe a second antenna. The Traveler 150 is large enough that I can fit everything I need into the one bag.
More details on transport of the Enhanced KX3 Travel Kit will appear here as I begin to work out the transportation and deployment logistics.