This second version of my K2 Travel Kit is a complete QRP station in a salvaged Samsonite hard-sided equipment case. (The original version of the K2 Travel Kit was carried in an old laptop PC soft-side bag.) The K2 Travel Kit is a true "Work in Progress" in that I am constantly changing the contents of the case as I learn what works and what doesn't.

The heart of the K2 Travel Kit is my 10-watt Elecraft K2, serial number 1872, revision 2.04P 1.09, with the KSB2 single-sideband, K160RX 160-meters, KAT2 audio filter/clock, and KNB2 noise blanker modules.

The K2's receiver performance, feature-mix, and low weight make it an extraordinary high-performance field rig, at least in those situations where size isn't a problem.

Batteries

Eventually, I might invest in the KBT2 Internal Battery Kit (2.9Ah gel cell) from Elecraft. Until I then, I will power the K2 and accessories with external gel cells of various sizes. When I want to travel light I carry a 5Ah battery which fits nicely in the Samsonite case. At other times, I take a 7Ah or 10Ah battery that is carried outside the case.

Solar Power

I have a pair of 5-watt photovoltaic panels and a WB8VGE Micro-M charge controller (photo | link). One of the panels is an inexpensive but relatively-large (approx. 12"x18") thin-film panel I purchased new at Harbor Freight (photo). The other panel, a Hoxan SP 5, is a polycrystalline panel (photo) and is much smaller (9"x10"). I purchased this second panel used at a hamfest but it still provides rated voltage and current. The Micro-M charge controller is wired to allow one or both of the panels to charge the battery while the battery is powering the rig. The charge controller and associated cables fit in the case but neither solar panel fits in the case.

Switching Power Supply

My old 3.5A portable switching power supply having died, I purchased a Mean Well 15v 4.4A (#P66A-4P2J) switching power supply (link) which is internally adjustable over the range of 13 volts to 16 volts. This power supply is slightly smaller than the my original one and easily fits in the Samsonsite case. I'm a little bit disappointed with this supply because it won't regulate with a very small load; this means I won't be able to use it as-is to float-charge a gel cell battery. I have added a hefty diode on the output and may eventually build an adapter that will provide a suitable load and current-limiting to allow me to use this supply to charge a battery. This power supply seems to be very quiet, RF-wise, although I have added ferrites to both the input and output leads, just in case.

Power Cable

I incorrectly thought the K2's rear-panel DC socket was a 2.5mm x 5mm coaxial power connector and I ordered a nice 24", 18AWG cable with the appropriate molded-on coaxial connector from Mouser (link; part number 172-4202). This cable works very well but I've since learned that the K2's DC socket is actually a 2.1mm x 5mm coaxial power connector, so when I need to make a replacement power cable I will look at Mouser for a cable with a connector of this size.

LDG Z11 QRP Autotuner

The K2 Travel Kit includes an LDG (link) Z11 QRP Autotuner. The Z11 is a latching-relay version of LDG's original QRP autotuner and draws no current once a match has been made. Here is a description of the Z11 from its manual:

The Z11 is a full featured low power automatic or semiautomatic antenna tuner designed for the HF ham bands (1.8 to 30 MHz). It will work with virtually any transceiver or transmitter providing between 0.1 and 30 watts continuous RF output (60 watts SSB or CW). The tuner uses the highly versatile "Switched L" configuration with 256 capacitor, 256 inductor and High/Low impedance settings to provide over one hundred and thirty thousand possible tuning combinations. The "L" network will match practically any coax-fed antenna (dipole, vertical, sloper, beam, etc). Long wires, and dipoles fed with ladder line can be matched using the LDG RBA-1 external balun, sold separately. Regardless of antenna type, tuning time is between 0.1 and 3.0 seconds, typically about 1.5 seconds.

The Z11 uses latching relays to switch tuning components in the "L" network. These relays hold the tuning configuration even when power is removed; once matched, the tuner automatically enters a low-power mode where it draws only 0.8 milliamps. Placing the tuner into "Standby" reduces power consumption to zero; the latching relays maintain the tuned configuration indefinitely. During tuning, the Z11 may draw up to 300 milliamps, but only for a few seconds. These exclusive LDG features make the Z11 ideal for portable, battery-powered HF operation.

I made a 4:1 iron-core balun (photos: external | internal) to use with the Z11 to allow me to use this tuner to match end-fed wires and balanced antennas. I plan to replace this with an air-core balun at some point.

The Z11 uses a 2.5mm x 5mm coaxial power plug. I've made a parallel power cable to enable me to conveniently power both the Z11 and the K2 from one source.

UPDATE: I had discovered that the Z11 wasn't working accurately; when it thought it had achieved a better than 1.5:1 match, I measured up to 2.2:1 SWR with an external SWR bridge. I performed a calibration according to the procedure sent to me by the LDG technician but this didn't significantly improve performance. I sent the Z11 back to LDG for diagnosis and repair, fully expecting to have to pay for this service. I was shocked and pleased when the Z11 came back to me repaired and upgraded to firmware version 1.6 (memory tuning upgrade), at no charge. That's customer service!

(Here is the Z11 manual as a 1.6 megabyte PDF file as downloaded from the LDG web site and here is a link to the firmware rev1.6 memory tuning upgrade being offered by LDG.)

Eventually, I might add the KAT2 internal automatic antenna tuner option to my K2. If that happens, I will no longer need to carry an external tuner in the K2 Travel Kit.

The descriptions of field-deployable antennas are now located here.

The K2 has an excellent built-in memory keyer so I don't need to carry an external memory keyer.

To key the K2, I previously used either a beautiful brass-and-rosewood K8RA P-2jr iambic paddle (photo | link) or a lightweight Whiterook MK-44 Pocket Mini Iambic Paddle (photo | link). However, since giving up on iambic keying I now use a lightweight Whiterook MK-33 Mini Single Lever Paddle (photo | link).

I've come to realize that when wearing gloves, as I will almost certainly be during the "Freeze Your B___ Off" event (link), a straight key would be easier to use well than would keyer paddles. In this situation, I will use my Whiterook MK-22 Pocket Mini CW Key (photo | link).

I've built an adapter (photos: 1 | 2) which allows me to have a straight key and a paddle connected to the K2 simultaneously; a pair of diodes allows the K2 to auto-detect when the straight key is being used. The circuit used in this adapter can be found on page 92 of revisions C and D of the K2 Owner's Manual and on page 99 of revision H of the K2 Owner's Manual.

I would very much like to have a small, lightweight bug for portable operations. I am told by Jim Wades, WB8SIW, that the E.F. Johnson Speed-X Model 114-520 is what I want and I have begun to search for one.

My K2 came to me configured for use with a Kenwood microphone but it didn't come with a microphone. I have reconfigured my K2 mic-jack for ICOM and use an ICOM HM-12 hand-mic.

At this point, SSB operation is of very little interest to me. If this changes, I will consider getting a Heil Handi Mic HC-5 (link) or the less glamorous--but far less expensive--MFJ-290K; with either mic, I will return my K2 to the Kenwood microphone configuration.

Field-Portable Lamps

I've built a couple of field-portable battery-friendly lamps for operation in the dark. They are based on high-intensity white LEDs salvaged from $1 notebook-PC USB lamps and are surprisingly bright. One lamp has one LED and is powered by a 1300mAH 6v lithium battery from a camera that long ago died. (photos: lamp off and on) I calculate that this battery will last for about 65 hours of continuous use. The second lamp contains contains two LEDs in series and is powered by a 9v transistor battery. (photos: lamp off and on) Both lamps were inspired by the Idea Exchange Quickie #51 by Joe Everhart, N2CX, in the Fall 2004 QRP Quarterly.

---