KX3 Application Notes & Operating Tips

Updated September 11, 2014

KX3 Operating Tips

KX3 Builder Alerts

KX3 Application Notes

KX3 Firmware Page

KX3 Product Page

KX3 MODs Order Page

KX3 Builder Alerts

Builder Alert

Description

Link / PDF

KXPA100 Kit Builder Alert #3: Operation with External Power Amplifiers

The KXPA100/KX3 combination is designed to interface with the KPA500 amplifier. If another power amplifier is used that presents more than +5V on the keying line, damage may occur to KXPA100 amplifiers with serial numbers less than 0700.

See separate
builder alert

KXPA100 Kit Builder Alert #2: Serial Data Noise Suppression

Under certain conditions when the KX3 and the KXPA100 are connected to a personal computer via the RS232 port, noise from serial data may be audible in the receiver. Adding a bypass capacitor eliminates this noise.

See separate
builder alert

KX3 Kit Builder Alert #1: Battery holder attachment screws

Some builders have reported the 2-56 flat head screws used to attach the battery holders in the KX3 do not seat smoothly against the plastic holder. The heads protrude upward and may strike one or more batteries. This is because the builder used screws from the Hardware Spares parts bag which were too long.

See separate
builder alert

 

KX3 Operating Tips

Operating Tip

Description

Link / PDF

Connecting KX3 to your Computer and Backup / Restore your Settings

To assist you in keeping your rig up and running for the long haul, we have engineered some "Good Housekeeping" features to ensure your radio can talk to your computer, back up your configurations and update your firmware.

application note

Maximizing Battery Life

The Elecraft KX3 has been designed with mobile applications in mind and that means that maximizing battery life can be important. Built into the KX3 are a number of features and capabilities that can be enabled separately. In this way, your battery life can be improved by minimizing the KX3's receive and transmit current drain.

application note

Using a Straight Key 

The KX3's attached keyer paddle, the KXPD3, is very flexible. However, the KX3 can actually handle 2 keys connected at the same time. Further, you can independently set up CW KEY1 and CW KEY2 to operate in any combination of Iambic or Straight key arrangements as you wish. This gives you maximum flexibility whether you are operating at home or mobile.

application note

Using APF for Weak Signal CW

Both the K3 and KX3 have an APF control (audio peaking filter). APF can be extremely effective when you're trying to copy weak CW signals buried in the noise.

application note

Using APF with K3 and KX3

Elecraft's K3 radio has quite a few features to assist the avid DX and Contester to dig out weak signals across the entire HF bands. This Operating Note is intended to highlight one of these features, the Audio Peaking Filter, or the APF, as it is generally called. Primarily intended for the CW operator, this feature enhances the already excellent DSP filtering built into the K3 and KX3.

application note

Using Dual Watch on KX3

Often a DX station will say "up 2" (or just "up") in order to move callers away from his own frequency. This allows everyone to still hear the DX station at all times despite dozens of stations calling.

application note

Using Rich Audio Features of KX3

While it contains a built-in speaker, many operators are finding far more benefits with the rich set of audio processing features in the Elecraft KX3. These features are intended to provide additional tools for the DX and Contesting operator to complete contacts. In order to use these features, however, the operator will need to use of stereo speakers or headphones.

application note

How to Lock VFO on KX3

Locking the VFO can be useful when operating mobile or portable, or if you just want to stay parked on one frequency for a long time and don't want to accidentally change it. Additionally, you can lock the VFO when operating on some of the digital modes, such as PSK31, Olivia, or JT65 where you will sit on one frequency and work multiple stations.

application note

 

KX3 Application Notes

Application Note

Description

Link / PDF

Elecraft KXPA100 + KX3 Power Calibration (Optional)

The KXPA100 is factory calibrated to an Elecraft lab-standard KX3 transceiver, measuring and saving expected KX3 drive power for a given KXPA100 output power. This alignment is performed separately on each band and is generally accurate. Some users report that when their specific KX3 is connected to the KXPA100 via the KX3- KXPA adapter cable, output power control is less accurate than desired. If this is the case, an optional calibration procedure pairs a specific KX3 to a specific KXPA100 and eliminates this power output discrepancy.

See separate application note

Tuning Noise Suppression Modification

Factory assembled KX3s from serial number 4668 up, and kits from serial number 4753 up that include the KXFL3 option have been shipped with the updated board.

KX3s with the KXFL3 filter installed may exhibit noticeable "zipper" noise when the VFO is tuned on quiet bands. (KX3s without the KXFL3 typically exhibit far weaker tuning noise.) To minimize the noise, you can do one or more of the following: set the VFO NR menu entry to ON; set the RX SHFT menu entry to 8.0; turn on the KX3's regular noise blanker, setting it to a low level. All of these settings are per-band, so they need only be used on affected bands. However, some audible artifacts may result when these techniques are used on very busy bands, and the use of RX SHFT=8.0 prohibits use of the filters on that band.

See separate application note

KX3 160M/80M Rx Performance Improvement

The KX3's receive dynamic performance has been improved by approximately 10dB on the 80M and 160M bands only. Operators on these bands may recoginze improved performance with strong local interference with this modification in place. This App Note discusses how to determine if you will benefit from the Performance Improvement and whether your radio needs to have it installed.

See separate application note

PER-BAND RXSBNUL with AUTOMATIC GAIN/PHASE NULLING

Allows receive opposite-sideband suppression to be optimized on any or all bands, relative to the normal level of suppression. Requires S9 to S9+30 signal source on each band to be adjusted. In addition to per-band FL1/2/3 nulling, separate per-band nulling can be done for the RX SHFT = 8.0 kHz menu setting.

See separate application note

KX3 VFO TEMPERATURE COMPENSATION

Requires approx. 50.0 MHz temperature-stable signal source (ideally, less than 2 Hz total drift over 30 minutes). Reduce error rates when using narrowband data modes such as JT65. See XG50 Manual  XG50 Order Page

See separate application note

KX3 Improving Internal Speaker Performance

If you have occasional loss of audio or crackling sounds coming from your KX3’s internal speaker, especially at high volume levels, you should check the speaker connector inside the KX3 to ensure it is plugged in correctly as shown below. The orientation of the connector is important.

See separate application note