This second version of my K2 Travel Kit is a complete QRP station in a salvaged Samsonite hard-sided equipment case. (The original 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, KAF2 audio filter/clock, and KNB2 noise blanker modules.

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 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 PV 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. The other panel, a Hoxan SP 5, is a polycrystalline panel 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

The 3.5A switching power supply (photo) I had been using while indoors with the QRP Station in a Bag and other portable rigs died while sitting on the shelf--it now blows the internal fuse in a spectacular fashion when power is applied. There's no hope of finding a schematic for this device which was manufactured in 1991 but I have attempted to troubleshoot and repair it using guidance found here. Update: I've been able to trace the fault to a shorted transistor, an ST HV82, but am unable yet to find a source for a replacement.

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 old one and easily fits in the case. I'm a little bit disappointed with this supply because it doesn't seem to regulate with a very small load which means I won't be able to use it as-is to charge a gel cell battery. I have added a hefty diode on the output and I will 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

Initially, I thought the K2's rear-panel DC socket was a 2.5mm x 5mm coaxial power connector. I ordered a nice 24", 18AWG cable with the appropriate coaxial connector molded on 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 Z-11 QRP Autotuner

The K2 Travel Kit includes an LDG (link) Z-11 QRP Autotuner. The Z-11 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 Z-11 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 have made a balun (photos: external | internal) to use with the Z-11 to allow me to use this tuner to match end-fed wires and balanced antennas.

Conveniently, the Z-11 and K2 use the same DC power plug. I've made a parallel power cable to enable me to conveniently power both devices from the one source.

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.

(Here is the Z-11 manual as a 1.6 megabyte PDF file as downloaded from the LDG web site and here is a link to a memory upgrade being offered by LDG.)

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.

I carried a Whiterook (link) MK-44 iambic paddle (photo) in the old QRP Station in a Bag. The MK-44 paddle is very lightweight and inexpensive and works surprisingly well. However, the K2 seems to be just too nice a rig to key with a plastic MK-44, so I now have a beautiful, brass-and-rosewood K8RA (link) P-2jr iambic paddle (photo) to use with the K2 in the K2 Travel Kit.

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 not very important to me. If I find that this changes, I will seriously consider getting a Heil Handi Mic HC-5 (link) to use with the K2.

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.

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