Home‎ > ‎The Elecraft K3 Book‎ > ‎

Chapter 3

Chapter 3:  K3 Operations

3.1    Introduction

In this chapter we cover the basics of CW, voice, and the digital operating modes. Here you will see configuration menu items, front panel controls, and operating hints that affect your CW, voice, and digital operations. Chapter 4 will describe more fully how to use DSP filtering, noise blanking, and noise reduction to reduce interference and noise. Chapter 5 gives more in-depth  coverage of the receiver, included the Sub receiver and antenna switching combinations. The transmitter is described in Chapter 6 and the KIO3 in Chapter 7.

3.2    Information for All Operating Modes

3.2.1    Power On and Off

. . .

3.2.2    Band and Mode Selection

. . .

3.2.3    Antennas and Antenna Tuning

. . .

Exercise

Give ANT1 the name TRIBD.

· · · 

Tap ANT until the ANT1 icon is displayed. Hold ANT. The first character in the label in the VFO B display flashes. Rotate VFO A to T, and then change VFO B to the next characters while entering RIBD with VFO A. Tap ANT when finished.

3.2.4    VFOs

. . .

Fine Tuning

By tapping FINE and displaying the Hz digit (Figure 3‑1) you tune in 1 Hz steps. The number of Hertz tuned in one revolution of the VFO knob is controlled by CONFIG:VFO CTS as shown in Table 3‑3.

Table 33.   1 Hz FINE tuning rate.

Tuning rate – 1 Hz Tuning Digit (Figure 3‑1)

Tap FINE

VFO CTS

(VFO Pulses/Rev)

Tuning

Step Size – Hz

Hz/Rev

100

1

100 Hz

200

1

200 Hz

400

1

400 Hz

 

 

Figure 31.  VFO A in fine tune mode (1 Hz resolution).

Rate Tuning

Tapping RATE allows faster tuning at two different rates with 10 Hz and 100 Hz display resolution. If you start in the fine tuning mode (Figure 3‑1) and tap  RATE once, you will tune with 10 Hz resolution as shown in Figure 3‑2 and Table 3‑4. Tapping RATE again gives you 100 Hz tuning resolution as shown in Figure 3‑3 and Table 3‑5. The number of kilohertz tuned per VFO knob revolution in each case is controlled by CONFIG:VFO CTS and VFO FTS as shown in Table 3‑4 and Table 3‑5.

 

Table 34. 10 Hz tuning.

Tuning Rate – 10 Hz Tuning Digit (Figure 3‑2)

Tap RATE Once

VFO CTS

(VFO Pulses/Rev)

Tuning

Step Size – Hz

Kilohertz/Rev

100

10

1

200

10

2

400

10

4

 

Figure 32. VFO A with rate 10 Hz resolution.

 

Table 35.  100 Hz tuning.

Tuning Rate – 100 Hz Tuning Digit (Figure 3‑3)

Tap RATE Second Time

VFO CTS

(VFO Pulses/Rev)

VFO FST

(Hz/Pulse)

Tuning

Step Size – Hz

Kilohertz/Rev

100

20

20

2

200

20

20

4

400

20

20

8

100

50

50

5

200

50

50

10

400

50

50

20

  

Figure 33. VFO A with rate 100 Hz resolution.

Coarse Tuning

Holding COARSE gives you the fastest tuning of all. The 100 Hz, 1 kHz or 10 kHz digit is tuned as shown in Figure 3‑4;  CONFIG:VFO CRS sets the tuning step size and the number of kHz tuned per VFO knob revolution for each mode as shown in Table 3‑6.

 

 

Table 36.  COARSE tuning rate.

Tuning Rate – Coarse Tuning

Hold COARSE

VFO CRS

Tuning

Step Size

Hz/Rev

Mode

0.1

100 Hz

10 kHz

SSB

CW

DATA

 

 

0.5

500 Hz

50 kHz

SSB

CW

 

 

 

1.0

1.0 kHz

100 kHz

SSB

CW

DATA

 

AM

2.5

2.5 kHz

250 kHz

SSB

 

 

 

 

5.0

5.0 kHz

500 kHz

 

 

 

FM

AM

9.0

9.0 kHz

900 kHz

 

 

 

 

AM

10.0

10.0 kHz

1.0 MHz

 

 

 

FM

AM

12.5

12.5 kHz

1.25 MHz

 

 

 

FM

 

25.0

25.0 kHz

2.5 MHz

 

 

 

FM

 

 

 

Figure 34. VFO A with coarse 100 Hz resolution.

 

 

Exercise

Set the coarse VFO tuning rate to 10 kHz/rev for CW and 100 kHz/rev for SSB.

· · · 

Set CW mode.

Set CONFIG:VFO CRS to 0.1.

Set SSB mode.

Set CONFIG:VFO CRS to 1.0.

 

 

Exercise

Set the VFO tuning rate to 400 Hz/rev when FINE tuning, 4 kHz/rev when tuning the 10 Hz digit (tap RATE), and 8 kHz/rev when tuning the 100 Hz digit (tap RATE again).

· · · 

Set CONFIG:VFO CTS to 400 and VFO FST to 20.

 

Direct Frequency Entry

. . .

3.2.5    Memories

There are 100 general purpose memories (00 – 99) that can store VFO A and B frequencies, operating mode, and other information. You can label each memory with up to five characters to easily remember what the memory is for. In addition, the four M1M4 keys can store up to four frequencies per band, i.e. per-band memories. Memories 0 – 9 can be used as quick memories accessible with only two switch taps.

General Purpose Memories

      Storing a General Purpose Memory (00 – 99)

. . .

Recalling a General Purpose Memory (00 – 99)

. . .

 

Quick Memories

. . .

Per-Band Memories

. . .

Storing a Per-Band Memory

. . .

Recalling a Per-Band Memory

. . .

Erasing a Memory

. . .

Adding a Text Label to a Memory

. . .

Using a Memory for a Band Select

. . .

Elecraft Frequency Memory Editor

. . .

3.2.6    Scanning

. . .

Band Scanning

. . .

Memory Scanning or Channel Hopping

. . .

 

Exercise

Set up memory 01 (the 1 key) to scan from 14.000.000 to 14.060.000 in CW mode. Set the memory label to SCAN.

· · · 

Select CW mode.

Enter or tune to 14.000.000 in VFO A and 14.060.000 in VFO B.

Tap V®M and rotate VFO A to select 01.

With the 01 flashing, rotate VFO B to the text positions and rotate VFO A to select the letter for the label.

Tap V>M to exit.

3.2.7    Filter and DSP Settings

. . .

Dialing in the DSP Bandwidth

. . .

Filter Presets

. . .

Normalizing the DSP Passband

. . .

Setting Your Own Normalization or Default Values

. . .

3.2.8    Noise Blanking and Noise Reduction

. . .

3.2.9    All Mode Squelch

. . .

Choosing All Mode or FM Only Squelch

. . .

Squelch Control with a K3 without a Sub Receiver

. . .

Squelch Control for a K3 with a Sub Receiver

. . .

Setting Up a Programmable Function Key for Squelch Control

You may want to assign a programmable function key as a shortcut to the CONFIG:SQ MAIN menu if you are using the independent squelch control shown in Table 3‑8.

1.     Open the CONFIG:SQ MAIN menu and then hold PF1 or PF2. The message PF1 SET (or PF2 SET) will appear. There are other programmable function switches too. See Chapter 2 for more information about the programmable function keys.

2.     Now, to set a new squelch level on the Main Receiver, hold PF1 or PF2 to go to the CONFIG:SQ MAIN or CONFIG:SQ SUB menu and then rotate VFO A to the desired setting.

If you want to control both the main and sub receiver's squelch, you will need to allocate two programmable function keys.

3.2.10 Operating Split

Many DXpeditions control their pileups by transmitting on one frequency and listening on another. Also, in many parts of the world, amateurs are not allowed to operate on frequencies that US amateurs use. Thus, these operators must transmit in their allowed band of frequencies and listen for US callers in theirs. A good operator should know how to operate split and how to find quickly the place where the DX station is listening.

In the K3 you can operate split if both VFOs are on the same band. Cross-band split is not allowed. You can operate cross-mode split between CW and SSB only.

To start, single tap or double tap A > B to transfer VFO A's frequency to VFO B. A double tap transfers the filter settings, preamp state and other settings to VFO B.

Operating Split with a K3 Without a Sub Receiver

Normally, VFO A is used for both transmit and receive. When SPLIT is held, VFO B becomes the transmit VFO, the SPLT icon turns on, the TX arrow points to  B , and the yellow Df LED is turned on if the receive and transmit frequencies or modes are different.

Your task now is to find the DX station's listening frequency. You will be listening to the DX station on VFO A and searching for the station that has successfully broken through the pile-up with VFO B. There are two ways to do this.

1.     When you hear the DX station call a station in the pile-up, hold the REV switch to reverse VFO A and VFO B temporarily. Quickly search through the pile-up using VFO A to find the station responding to the DX. When you find it, release REV and get ready to call the DX on the next over.

2.     A second option, although not a good as the first, is the following. When you hear the DX station go back to a station in the pile-up, tap the A/B switch to reverse VFO A and VFO B. Quickly search through the pile-up using VFO A to find the station going back to the DX. When you find it, tap A/B again and get ready to call the DX on the next over. This method is less desirable than the first because if you forget to reverse the VFOs when you call, you will be calling on the DX frequency, which usually earns approbation from the pile-up.

Operating Split with a K3 with a Sub Receiver

Finding the station that is working the DX is far easier with a Sub receiver because you can listen to the DX on the Main receiver (VFO A) in your left ear while you are tuning VFO B and listening to the Sub receiver with your right ear for the frequency in which to dump your call. You do not have to use the REV or A/B keys, but you do have to turn on the Sub Receiver by tapping SUB and enter split mode by holding A®B/SPLIT. Don't forget to do this to avoid transmitting on the DX frequency! When you are operating split mode, the VFO B controls the transmit frequency. If you are not in diversity mode (see Chapter 5) you may hold A/B/B SET  and set up the Sub Receiver's filtering and mode independently of the Main Receiver. For example, you may want to have a narrow filter on VFO A to listen to the DX and a wide filter on VFO B to scan the pileup. Otherwise, double tapping A>B transfers all of the Main receiver's configuration to the Sub receiver.

3.2.11 Using an External Speaker

. . .

3.2.12 Audio Effects

. . .

3.3    CW

3.3.1    Getting Started

. . .

CONFIG Menu for CW

. . .

CW Front Panel Controls

 . . .

Connecting a Key

. . .

 

Exercise

You are operating at the scene of a disaster using a low antenna and low power while passing health-and-welfare traffic. You can hear the SSB station on the other end but it can't hear you very well. You would like to be able to listen on SSB and send on CW. What configuration menu item to you use to activate this cross-mode transmission.

· · · 

Open the CONFIG:CW WGHT menu and tap the  1  key to set SSB +CW.

 

 

Setting Your Sidetone Pitch

Many people have a "sweet spot" in their hearing that makes it easy to hear certain tones. Usually as we grow older, that tone or pitch may go down in frequency. You should adjust your sidetone pitch, as described in Table 3‑10, to make it easier to zero beat a station you are calling.

Zero Beating the Station

You should try to match your sending frequency with that of the station you are going to call. This is called zero beating, and when done properly the operator of the station you are calling will hear your signal at his or her sidetone pitch. Being able to zero beat another station rapidly is an important skill for the serious CW operator. For example, you might be chasing a DX station that is operating split and rapidly working stations in a pile-up. Finding the last station worked and zero beating that frequency will greatly enhance your chances of working the DX.

The term zero beating derives its name from the beat tone we hear when we listen to two, closely spaced, audio tones. To zero beat a station, you must match the tone of the station to which you are listening to your sidetone. When they are matched, the beat note that you hear will go to zero. Now you are on the sending station's frequency. The K3 offers three ways to ensure you will be calling on the right frequency.

1.     Tapping CWT changes the S-meter display to that shown in Figure 3‑10. As you tune across the CW signal you will see the black tuning indicator move from too low, to zero beat, to too high. If no bar appears in the tuning area, you may have to adjust the tuning threshold value by holding TEXT DEC and tuning thr (threshold) to a lower value.

2.     If CWT is turned off, you may use a manual method to zero beat. Tap the SPOT switch. This turns on your sidetone generator, which you will hear superimposed on the signal you want to zero beat. Tune the VFO and when the beat note goes to zero, you will be zero beat.

3.     If you find pitch matching difficult, an auto-spot mode is available. Turn CWT on and then tune in a station using a narrow receive bandwidth (200 to 500 Hz). Tapping SPOT will automatically set your VFO to the zero beat frequency.

 

Figure 310. CWT display.

 

 

Exercise

Tune in a strong CW signal or a carrier with CWT turned off and tune the VFO so that the received signal is as close to your sidetone as you can. Now tap the SPOT switch and listen for the beat note. Fine tune the VFO so that your VFO zero beats the received signal. Are you able to hear the beat note go away as you get close to the zero beat frequency?

 

Exercise

Tune in a strong CW signal or a carrier with CWT turned on and tune the VFO so that the received signal bar is close to the CWT indicator. Now tap the SPOT switch. Your VFO should automatically adjust frequency to put you on zero beat.

 

Exercise

You can train your ear to be better at zero beating by first tuning in a strong CW station and trying to get as close to your zero beat frequency as you can without using the spot tuning aids. Note the VFO frequency, then turn on CWT, and tap the SPOT switch. If your VFO doesn't change very much, you are doing a good job.

 

Dual Passband CW Filtering

. . .

Audio Peaking Filter – APF

 An audio peaking filter was added to the K3's firmware suite starting with version 4.22. Used only in the CW mode, the APF provides a very sharp audio filter that is effective in pulling weak CW signals out of the noise. CW signals seem to "pop" out of the noise.

1.     Set CONFIG:DUAL PB to APF.

2.     Hold XFIL/DUAL PB to enter APF mode. Hold XFIL/DUAL PB again to return to normal filtering.

3.     You can use APF on the Sub receiver by turning the Sub on, entering b SEt mode and then holding XFIL/DUAL PB. You must remain in b SEt mode to tune the APF using SHIFT.

When in APF mode, a display similar to Figure 3‑11 is shown. See Figure 3‑12.  SHIFT controls the center of the filter in 5 Hz steps and the VFO B display area shows the current center frequency plus APF to let you know the APF is engaged and not dual passband. APF mode works independently for the main and sub receivers and for filter presets I and II.  WIDTH changes the width of the APF from about 50 Hz to 2.8 kHz.

.

 

Figure 312. APF display

Hints from Elecraft Users for using the APF

1.     Use 1 Hz VFO tuning (tap FINE) to carefully tune the station to the peak of the filter.

2.     Some users find that a wider filter, 400 Hz, seems to work better to reduce ringing that is heard in the very narrow (50 Hz) DSP filters.

3.     Reducing the AF gain may help the signal pop out of the noise when you have tuned to the signal.

4.     It is useful to set one of the filter presets to operate with APF and the other without to be able to rapidly switch between the two modes.

 

3.3.2    Computer Operated CW

There are at least four ways to key your K3 with a computer. The first is to use the RTS or DTR signals in the RS232 serial port connector. Your computer program must be able to send CW (and operate the push-to-talk, if needed) by activating the RTS and DTR lines. The K3 converts the RS232 signal levels (see Appendix B) to the required computer logic levels. The CONFIG:PTT-KEY menu allows you to choose which of the two RS232 signals is used for PTT and which is used for Keying. Table 3‑12 shows the CONFIG:PTT-KEY menu to set up for computer keying and PTT. When using this method, make sure CONFIG:PTT-KEY and the computer program keying and PTT choices are the same.

Another way to key the K3 is to pull the KEY input line low with a straight key, bug, or a computer-generated signal. If you are using a computer serial port signal to do this, you must use a level converter such as shown in Figure 3‑13 to convert the RS232 serial port voltage to the computer's logic levels.

You may use both the internal keyer using the PADDLE input and a computer keying the KEY line together. This is useful, for example, if you are using a contest logging program to send computer generated CW and you would like to use the paddle say hello to a friend. The sending speeds can be different with the internal keyer speed set by the front panel SPEED  control and the computer speed set by the logging program.

A third way to send CW from a computer is by using a keyer that uses the WinKey[1] or similar compatible chip. Most  logging programs aren't very good at sending CW – they use routines that make poor use of processing cycles and the result is choppy CW. The WinKey is a popular solution. The logging program sends text to WinKey via a serial or USB port and the WinKey converts it to CW, which then goes to the KEY input of the radio.  The WinKey also accepts a paddle, so the operator can send CW from both the computer and the paddle. You can also use your paddle in the PADDLE input and send CW at a different speed than the WinKey. The WinKey has both CW and PTT outputs for two radios that can be switched by the logging program, so the WinKey is quite popular with contest operators. When using WinKey, PTT-KEY should be set OFF-OFF.

Finally, you can send and receive decoded CW with the K3 Utility program's terminal program. Click the Terminal tab and click the CW button. Hold CWT/TEXT DEC to turn on text decoding. Decoded CW will be in the upper window. Type text to be transmitted in the lower window and click Transmit.

 

 

Table 312.  PTT-KEY config menu.

Config Menu

Setting

Description

PTT-KEY

OFF-OFF

No computer keying through the RS232 serial port (default)

rtS-OFF

RTS controls PTT, no CW keying

dtr-OFF

DTR controls PTT, no CW keying

OFF-rtS

No PTT, RTS controls CW keying

OFF-dtr

No PTT, DTR controls CW keying

rtS-dtr

RTS controls PTT, DTR controls CW keying

dtr-rtS

DTR controls PTT, RTS controls CW keying

3.3.3    CW Text Decoding

. . .

3.3.4    CW Message Memories

. . .

Editing CW Memories with the K3 Utility Program

. . .

Playing Back a Message 

. . .

Message Erase

. . .

Auto-Repeat a Message

. . .

Chaining Messages

. . .

Message Memories and Programmable Function Keys

. . .

3.4    SSB

3.4.1    Getting Started

. . .

Main Menu for SSB

. . .

Voice Monitoring

. . .

Transmit Audio Equalization

The K3 provides eight bands of transmit (and receive) audio equalization. You can use this feature to compensate for variations in microphones and your voice. For example, if the microphone you are using does not have bass response to your liking, you can compensate for that by adjusting the gain in the lower frequency bands.

1.     Set up voice monitoring as above and use your headphones to listen to your signal. [2]

2.     Hold TEST to put the K3 into transmit test mode. The TX icon will start to flash. You can also set the PWR to zero to not transmit on the air.

3.     Access the MAIN:TX EQ menu. The VFO A display area will show eight bands, whose center frequencies are shown in Figure 3‑15. Tapping keys  1   8  and tuning VFO A adjusts the microphone gain to a maximum of plus or minus 16 dB. As you rotate VFO A, the gain or attenuation in dB is shown in the VFO B area.

4.     You can tap CLR to set all bands to 0 dB.

5.     If using ESSB (see below), a separate set of equalization bands is used. The MAIN entry menu changes to TX*EQ.

6.     Thanks to K9YC for the following comments on equalizing your transmitter:

a.     Typical settings for SSB with most mics would have bands 1 and 2 set to -16 dB, band 3 to some moderate level of gain reduction (-6 to-10 dB), and the remaining bands set flat (0 dB).  Mics that are excessively bright (most Heils, for example), may also need some reduction for bands 7 and/or  8.

b.    Professional mics will need full gain reduction (-16dB) on bands 1, 2, and 3, 6 dB reduction on band 4, 6 dB increase on band 7, and 10 dB increase on band 8.

c.     In general, increased gain should be avoided because it makes it more likely that the audio part of the DSP chain will run out of headroom and hit a digital clip.

d.    The only use for which bands 1 and 2 should not have deep reductions is the ESSB mode. Any power transmitted in these bands is wasted power from a communications point of view – virtually all speech intelligibility is carried between 400 Hz and 5 kHz, and that low frequency energy can use considerable transmit power that is far better used to carry mid-range audio where the intelligibility is.

 

Figure 315.  Transmit audio equalization.

Microphone Gain and Compression Setting

. . .

Transmit Noise Gate

. . .

VOX Mode Set up

. . .

Power Level for Voice Modes

. . .

Extended Single Sideband (ESSB)

. . .

3.5    AM

Your K3 must have a 6 kHz (AM) or 13 kHz (FM) filter installed to transmit and receive AM. You can select two AM detection schemes by holding MODE . Envelope detection (AM) may suffer severe distortion when selective fading of the AM carrier occurs. Synchronous detection (AM-S), which phase-locks an oscillator to the AM carrier, solves this problem.

 

3.6    FM

A 13 kHz (FM) filter is needed on the RF board to transmit and receive FM. If you wish to use the Sub receiver (if installed) for FM reception, an FM filter is needed there too. When in FM mode, the filter widths are fixed; presets and filter controls are not used. FM simplex is the default mode and the CONFIG:FM MODE menu allows you to turn FM mode off.


Repeater Operation

. . .

3.7    Digital Modes

The K3 can send and receive radio teletype (RTTY), PSK-31, and AMTOR/PacTOR. You can get started using RTTY and PSK-31 without a computer by using the internal keyer in data modes. See Section 3.7.3. With a computer and sound card, it can also send and receive other digital modes, such as AMTOR, PacTOR and WSJT, for which software to generate and detect signals is available. Using the K3 on digital modes is very easy because you do not have to add external interface circuits unless you wish to use direct FSK keying such as FSK D and PSK D.

3.7.1    Data Modes

The K3's digital data mode is selected by tapping MODE until the DATA icon appears. Then, hold AFX/DATA MD and choose one of the following modes by tuning the VFO B knob.

In the following sections, a "D" data mode (FSK D, PSK D) means that direct modulation is used to generate the digital transmitted data. With direct modulation, the FSK IN pin in the ACC socket, the internal keyer, or an ASCII data stream input on the RS232 serial port generate direct FSK. In "A" modes (DATA A, AFSK A), your computer generates the signal as an audio tone to be sent to the K3, which is then transmitted as a SSB signal.

DATA A

 DATA A can be used for all audio-shift transmission modes, including AFSK and PSK-31. VFO A shows the transmit suppressed-carrier frequency and USB is normal for DATA A. Compression is automatically set to 0 to reduce transmitted signal distortion.

AFSK A

AFSK A is also an audio-shift transmission but is optimized for RTTY. VFO A displays the RTTY mark frequency and LSB is normal. The built-in text decoder (see Section 3.7.2 below) and the dual-passband RTTY filter can be used. If a computer is used to generate AFSK A, two stereo cables are needed between the K3 and the computer. See Figure 3‑19.

FSK D

 FSK D is identical to AFSK A except that direct modulation is used via the ACC socket FSK IN pin. The internal keyer (see Section 3.7.3), or an ASCII data stream input on the RS232 serial port also generate direct FSK. The built-in text decoder as well as the dual-passband RTTY filter works in this mode. When direct FSK keying via the FSK IN pin in the ACC socket is used, a cable from the computer's serial port with an RS232 level-shifter is needed. A stereo cable is used between the K3's line out and the computer's line in jacks.

PSK D

 PSK D is a direct modulation mode for PSK-31. It decodes and displays PSK-31 signals on the built-in text decoder. You may transmit via the internal keyer or an ASCII data stream input on the RS232 serial port. You may use auto-SPOT when CWT is enabled to help with the critical tuning needed for PSK-31 signals. At the time this is written, you cannot use the FSK keying input on the ACC socket to generate PSK-31 transmissions.

 

3.7.2    Data Text Decode

Tips for Decoding Data Mode Text

1.     In AFSK and FSK modes, the RTTY dual-tone filter may help (hold XFIL/DUAL PB). See Figure 3‑18.

2.     Make sure the correct data rate is selected. 45 bps is the most common rate.

3.     Tap FINE tuning when decoding PSK-31 signals. Use SPOT or auto-SPOT and then tune slowly in 1- Hz steps until recognizable words appear. (See Zero Beating the Station in Section 3.3.1 above.)

4.     When calling CQ in PSK-31 mode, keep RIT on to fine-tune any responding stations without moving your transmit frequency.

5.     In difficult conditions, reduce WIDTH to 50 Hz for PSK-31 and 200 Hz for RTTY.

 

Figure 318. RTTY dual-tone filter.

 

 

 

3.7.3    CW-to-Data

. . .

3.7.4    Data Mode Computer Connections

. . .

K3-to-Sound Card for AFSK A and DATA A

 Figure 3‑19 and Figure 3‑20 show the Line Out of the K3 connected to the Line In of the computer or the Mic In of a laptop. This should be a 3.5 mm (1/8") stereo (TRS, tip-ring-sleeve) cable and it transfers received audio from the K3 to the sound card. The computer Line Out or laptop Headphones output is connected with a stereo cable to the K3 Line In. This configuration is used for AFSK A and DATA A modes, where the sound card generates audio transmit tones. With this set up you will enable VOX and then the audio tones arriving on the Line In port will key the transmitter.

An important connection that helps reduce noise is the heavy ground braid between the computer and the K3. A good source of grounding copper braid is the shield from RG-8 or RG-11 coax. For more information, see K9YC's excellent presentation on the use of grounding, and other techniques, to reduce noise in your system.[3]

Figure 319.  K3-to-sound card for AFSK A and DATA A modes.

 

 

K3-to-Sound Card for FSK D

. . .

Send and Receive ASCII Data

. . .

3.7.5    Radio Teletype (RTTY)

You can use two modes for RTTY. Audio Frequency Shift Keying (AFSK A) uses a computer soundcard to generate tones at the mark and the space frequencies. A stereo cable connects the computer's Line Out or Headphones jack to the K3's Line In. The computer sound card's Line In or Mic receives the received audio tones from the K3's Line Out jack to decode them for your display (Figure 3‑19). You may set the K3 to transmit using VOX or, if your RTTY software supports it, you may use a PTT signal using a serial port. AFSK uses lower sideband, which is more-or-less the standard used for RTTY.

AFSK A is frequently chosen for RTTY because once you are set up to use your computer's sound card it is easy to use some of the other sound card modes such as PSK-31 DATA A.

Frequency Shift Keying (FSK D) uses the computer to generate a keying signal, usually on a serial port. This, and an associated PTT signal, must be converted from RS232 signal levels to transistor switch closures and connected to the ACC socket on the K3's back panel. This direct keying mode generates mark and space tones at the frequencies set up by the K3's SPOT/PITCH menu. The CONFIG:FSK POL menu can change the polarity of the transmitted data, with 1 being normal and 0 reverse polarity. The computer sound card's Line In or Mic receives the received audio tones from the K3's Line Out jack to decode them for your display (Figure 3‑22).

There are many programs for your computer that will run RTTY, such as MMTTY and Ham Radio Deluxe, as an internet search will show.

Receiver Set Up

. . .

Transmitter Set Up

. . .

Troubleshooting

. . .

Setting Up for FSK RTTY

. . .

Receiver Set Up

. . .

Transmitter Set Up

. . .

Troubleshooting

. . .

 

3.7.6    PSK-31

You must use the DATA A mode for audio shift keying, which is normal for most computer PSK-31 programs. The direct keying PSK D mode may be used when sending PSK-31 with the internal keyer, the K3 Utility program, or PSK-31 computer software that can send ASCII text to the K3 using the serial port.

Setting Up for PSK-31 DATA A

. . .

Receiver Set Up

. . .

Transmitter Set Up

. . .

Troubleshooting

. . .

 

Setting Up for PSK D PSK-31

. . .

Receiver Set Up

. . .

Transmitter Set Up

. . .