Auteur Sujet: Annual tips for getting the most out of your rig at Field Day - Spécial Elecraft  (Lu 5600 fois)

Hors ligne VE2UGO Hugo

  • Membre guru
  • *****
  • Messages: 871
  • Rapid Deployment Amateur Radio
Wayne Burdick, vient de publier ce texte afin de faciliter les opérations lors de Field Day.

Bonne lecture!

Here are my annual tips for getting the most out of your rig at Field Day. (Some are Elecraft-specific--thanks for the bandwidth!)

1. BATTERY LIFE: To conserve battery life, use hunt-and-pounce rather than calling CQ, and use lower power output when possible. This is especially practical on a very quiet band, such as on 15 or 10 meters in the afternoon and early evening. You'll be amazed at how many stations you can work with one watt when these higher bands are open.

- Lower power can also keep the rig cooler. (As will operating in the shade! At least keep the heat sink in the shade, if you can. On the KX3, the heat sink occupies the back edge and bottom of the enclosure. On the KX2, it's the right side panel.)

- To reduce supply current in receive mode, use headphones rather than the internal speaker, and if lighting conditions permit, turn off the LCD backlight (MENU:BKLIGHT).

- The KX2 has an amp-hour monitoring feature. Tap DISP and rotate VFO B to obtain this reading. To clear the AH value to zero, go into the AMP HRS menu entry and hold CLR.

- The KX3 automatically switches the power amplifier to a more efficient setting based on the mode, supply voltage, and power setting. You can tell that power-saving mode is in effect by a decimal point after the 'W' in the power value (e.g., "5.0 W."). In SSB and audio data modes, the applicable level is 3.0 watts.

2. QRP HUNT-AND-POUNCE TIP: This type of operation can be greatly enhanced by using dual watch (KX2/KX3) or a sub receiver (K3/K3S). It allows you to keep one VFO on a station you're waiting to call, while tuning the other VFO to look for the next station to call. (If you beat my own 1B-Battery score because of this tip...guess I asked for it :)

3. ANTENNA SELECTION: The general rule is, "the longer and higher, the better," suggesting wire-in-a-tree antennas. (If you're lucky enough to have a portable yagi, that's even better.)

- When winding antenna wire for storage, wind it in a figure-8 pattern. When you release the bundle later, it will spring out easily without kinks or tangles.

- An electrically short whip will work in a pinch, but you'll typically realize a 5 to 15 dB improvement on both RX and TX with an an-hoc wire antenna.

- Most Elecraft rigs have an optional internal, wide-range ATU that can tune random wire antennas on all or some bands. Once the antenna is set up, go into the ATU menu entry on each band of interest and hold CLR to clear out all L-network memories. You may then only have to do ATU TUNE once or twice per band. Data for your home antennas may be stored for up to 32 smaller segments on each band.

- When connecting a wire directly to an ATU, avoid wire lengths that are multiples of a half-wave on any target band (unless you're using a half-wave antenna with a matching transformer at the rig). 26' and 52' (approximately) work well for 40-6 meters in most cases, and 52' will usually allow matching on 80 m as well.

- You can use these same lengths for counterpoise wires, which are essential for low loss on transmit. Without at least one counterpoise wire, your transmitted signal will be an additional 10-20 dB lower, even if the ATU can match the antenna.

4. ANTENNA SPACING: If you're using more than one transmitter, try to keep the antennas as far apart as possible and perpendicular to each other. This is a good practice with all FD stations, because it can prevent receiver de-sensing and intermodulation distortion. If two stations unavoidably have their antennas in each other's near fields, you can dig into a pretty deep bag of tricks, including reducing preamp gain or turning on the attenuator. These settings are per-band on all Elecraft rigs.

- KX3: Try setting MENU:RX SHFT to 8.0 rather than NOR. (The KX2 always uses 8 kHz shift.)

5. OSCILLATOR ISOLATION: The KX2 and KX3, like other radios with a quadrature direct-conversion architecture, use a VFO (local oscillator) running at or very close to the operating frequency. If you have another radio on the same band as the KX2 or KX3, and the antennas are close together, the other radio may be able to hear the rig's oscillator when they're both tuned close to the same frequency.

To prevent this entirely, the KX3 includes an isolation amplifier that keeps the oscillator from radiating back through the mixer. Normally this amplifier is turned off to save about 15 mA of receive-mode current drain. To turn on the isolation amp, set MENU:RX ISO to ON. This has no effect on performance.

The KX2 doesn't have an isolation amp, but isolation is very good when the preamp is on.

Have fun!