Antennas, Operation – Elecraft KX3-4M User Manual

Page 4

 Turn the KX3 power off, then on again by tapping the

B AND–

and

AT U T UNE

switches

simultaneously for the changes to take effect.

1) Do not turn off your power supply. Always use the front panel switches to turn power

on and off. Although disconnecting your external power supply when no batteries are
installed in the KX3 will often cause no harm, certain parameter changes may not be saved
and it is possible to corrupt some data that could require you to reload the firmware.

 After cycling power hold

ME NU

to re-enter the menu and then turn the VFO knob to

BND MAP.

Tap the

B AN D–

and

B AN D+

switches as needed to display

144

for the 2 meter module or

for

the 4 meter module and then turn the VFO knob, if needed, to display

In.

 Tap the

M E NU

switch to exit the menu.

Antennas

Connect your 2 or 4 meter antenna to the female SMA connector mounted on the KX3’s right end plate.
Note that when you select the 2 or 4 meter bands,

ANT2

appears on the LCD indicating that the SMA

connector is in use (see Figure 1 on page 5). The BNC connector is used only for the 160 through 6 meter
bands.

The antenna system must present a load very close to 50 ohms (have a low SWR) for full power output and
efficient operation. The KXAT3 Automatic Tuner option, if installed, does not function on 2 or 4 meters.
The 2 or 4 meter RF output is completely separate from the KXAT3 signal path.

Antenna polarization (vertical or horizontal) has more effect on signal strengths in the VHF range than it
does on the HF bands. Vertical polarization is normally used for FM communications to match the
polarization of mobile whips and ‘rubber duck’ antennas on hand held radios. Horizontal polarization is
most common for SSB, AM, CW and Data modes.

Operation

Complete operating information is included in your KX3 Owner’s Manual. The following is specifically to
help you get the most from your KX3-2M or KX3-4M in FM mode. Additional information about your
KX3-2M or 4M may be found in the FAQ on the Elecraft web site:

http://www.elecraft.com/manual/KX3-2M%20FAQ.htm

Frequency Stability

The standard (uncompensated) frequency stability is sufficient for FM or AM operation. For CW, SSB or
Data use, it will be necessary to perform the KX3 extended VFO temperature compensation procedure,
providing typical stability of about ± 10 Hz on 2 or 4 meters. This is compatible with 170-Hz-shift RTTY
but may not be compatible with some narrowband modes such as JT65 or WSPR. The extended
temperature compensation procedure is available on the Elecraft web site:

http://www.elecraft.com/manual/KX3%20Custom%20VFO%20TC%20rev%20A9.pdf

VHF Operating Frequencies

The VHF bands are typically organized by operating mode and type of communications, with frequencies
set aside for beacons and sub bands reserved for weak-signal work to avoid interference from local stations.
Also, frequencies are set aside for FM communications along with input-output frequency pairs for FM
repeaters to avoid interference with other modes. More information about the band plans can be found at

www.70mhz.org

for 4-meter operation and

www.arrl.org/band-plan

for 2-meter operation.

This manual is related to the following products:

KX3-2M