ELECRAFT K144XV Especificações descarregar pdf (Página 18)

Using the K144XV

The K144XV 2-meter option adds full coverage of the 2-meter band (144-148 MHz) to the K3. The K144XV is

a transverter, taking RF in the 28-30 MHz range from the K3, converting and amplifying it to provide up to 10

watts RF output in the two meter band. Two meter signals received by the K144XV are down-converted to the

28-30 MHz range and passed on to the K3 receiver. (The 28-30 MHz range is referred to as the I.F., or

intermediate frequency.)

To provide full 144-148 MHz coverage, the K144XV has two tuning ranges: 144-146 MHz and 146-148 MHz.

Both ranges use the same 28-30 MHz I.F., thanks to the use of two different conversion oscillator crystals (116

and 118 MHz). As you tune across the 146-MHz boundary, the K144XV automatically switches between the

two crystals.

The K144XV is fully-integrated into the K3, so most of the K3s controls behave exactly the same as they do on

the other bands. Differences specific to two meter operation are described below.

VFO Tuning

Tapping BAND selects the 2-meter band in normal rotation after the 6 meter band and before returning to the

160 meter band. Optionally, you can use direct frequency entry to select any frequency in the 144 – 148 MHz

range. You can store 2-meter frequencies in any of the K3’s 100 general-purpose memories as well as the per-

band quick memories as described in the manual.

If you use a number of different repeaters on 2 meters, you may wish to store information for each one in a K3

memory. You can assign up to 5-letter labels to each memory, such as an abbreviation of the repeater’s location

or call sign. If you want to designate a sequential group of memories for “channel hopping,” use ‘*’ as the first

letter of each label in that memory range. See Channel Hopping in the K3 manual.

When tuning across the 146 MHz boundary, you may hear a “click” from a relay in the K144XV module as it

switches tuning ranges. That is normal. You should not set up continuous scanning across this boundary, as it

would switch crystals rapidly, reducing the life of the relay.

The accuracy of the K3 frequency display on 2 meters depends upon entering the correct offset values into the

K3’s configuration menu (see Frequency Calibration on page 19). A small amount of frequency drift during

warm-up, or when switching from one range to the other, is normal.

Output Power Adjustment

PWR controls the K144XV output power. The 144- MHz output power is not measured directly. Rather the

28-MHz drive power is measured and displayed in mW and dBm, just as when using an external transverter.

The K3’s bar graph shows the drive power in tenths of a mW, so 1 on the bar graph indicates 0.1 mW drive and

10 on the bar graph indicates 1.0 mW drive.

The drive power has a range of 1.5 mW down to 0.1 mW. The K144XV has a gain of about 40 dB, which means

that typically 1.0 mW of drive will produce the maximum 9 to 11 W output. If 1.0 mW drive does not produce

at least 9W output as measured by a known, calibrated 144MHz wattmeter, first calibrate your K3’s 1.0 mW

output using the K3 Utility program and a 50-ohm dummy load on the K3’s rear-panel XVTR OUT jack.

Consider using more than 1.0 mW of drive only if the output is still below 9 W after completing the 1.0 mW

calibration. Many wattmeters have no more than 10-20% accuracy at 10W, so a reading of 7 to 10 watts is not

unusual.

NOTE: The left side panel of the K3 may become very warm to the touch during continuous key-down

operation at full power. This is normal.

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