GW4ALG's QRP Radio Pages

[ GW4ALG went QRT in February 2007 ]

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Elecraft K2 transceiver


The K2 QRP transceiver is available as a kit from Elecraft of Aptos, California. 

I completed the construction of my K2 (serial number 2454) in February 2002, and am delighted with:
- the quality of components;
- the 'fit' of the mechanical components;
- the detailed instructions and circuit information;
- the after-sales/helpdesk support; and,
- the performance of the completed transceiver.

The picture below shows a K2 (with a K1 transceiver on top).

k1_k2.jpg (23499 bytes)


More pictures of the K2 can be seen by clicking on the thumbnails below:

k2_front.jpg (43472 bytes)                           k2_rear.jpg (39887 bytes)

The basic K2 is very nice to use; has lots of functions brought out to front panel controls; and many built-in features.  I have also fitted the following options:160 m module; automatic ATU; and the RS-232 interface. 

For 60 m (5 MHz) operation, I use an external VXO transmitter and a receive converter.

When operating CW contests with the Elecraft K2, I use the 'SD' computer logging program (DOS version) on an old Toshiba laptop (Model T1850).  The Elecraft RS-232 interface provides rig control; and a homemade computer interface is used for keying the K2 from the parallel port.


Basic Features

The basic K2 is a QRP CW transceiver that is packed with features.  A partial feature list follows:

  • Twin VFOs with selectable Band Up/Band Down

  • Direct frequency entry and ten memories

  • Independent receiver & transmitter tuning (RIT/XIT)

  • Variable VFO tuning rate

  • ‘S’ meter, power meter, and digital frequency readout

  • Variable output power (0.5-10 watts)

  • CW operation on 8 bands (10/12/15/17/20/30/40/80 m)

  • Full QSK/break-in operation

  • Built-in electronic keyer with nine 255-character memories

  • Variable bandwidth IF filter

  • SSB receive mode

  • 12 V operation (10 –15 VDC)


Internal Options

The basic K2 was designed with lots of upgrade options in mind.  Here are some of the options available for the K2:

  • SSB Option

  • 160 m board + second receive antenna port (works on all bands)

  • Audio Filter + Clock

  • Noise Blanker

  • Internal Automatic Antenna Tuner

  • Internal 2.9AH Battery

  • AUX I/O RS-232 Interface



[1] K2 Product Review: (QST, March 2000)

[2] K1 Product Review: (QST, March 2001)

[3] Building & Using The Elecraft K2 HF Transceiver by Neill Taylor G4HLX (Practical Wireless, December 2002, p38).

[4] Some Experiences with the Elecraft K2 HF Transceiver by Dave Sergeant G3YMC and Bob Whelan G3PJT (RadCom, March 2003, p28).

[5] Elecraft Contact Information:

Phone: 831-662-8345
FAX: 831-662-0830
Elecraft Web Site:
Email (sales):
Email (support):
Address: Elecraft, Box 69, Aptos, CA 95001-0069

a) 'QST' is the monthly journal of the American Radio Relay League (ARRL).
b) 'RadCom' (Radio Communication) is the monthly journal of the Radio Society of Great Britain (RSGB).


Q1.  What gauge solder did you use?
A1.  I used 'Multicore' 60% tin/40% lead, 0.9 mm (20 SWG), but it is not critical. The components supplied with the kit are first class, having leads with excellent solderability characteristics.

Q2.  Have you carried out any modifications to your K2?
A2.  Yes.  Here is a summary:
1) installation of an audio network in the receive audio path (to provide more roll-off at high audio frequencies);
2) during construction, I drilled two 7 mm holes in the RF board (so that I could screw the PA transistors directly to the heatsink).  This was fairly high risk, because I had populated most of the board by the time that I decided to provide a more positive thermal contact between the PA transistors and the heatsink;
3) AGC modification (to prevent receiver overload in the presence of very strong local signals);
4) VFO modification (to cure the 'walking VFO' problem);
5) Volume control modification (to cure the 'scratchy potentiometer' problem).




Computer Keying Interface for the K2 ]