How to Program a K4 — Step by Step

Elecraft's direct-sampling flagship, designed to be taken apart. A seven-inch touchscreen with dual panadapters, two receivers as standard, and a radio that is genuinely a networked computer — it can serve its own front panel over the internet with no PC in the middle.

This page covers: Elecraft K4, Elecraft K4D. They share the same firmware, so the steps below are identical on all of them whatever name is printed on the front.

Two things about this radio have no equivalent on a Japanese rig

First, there is no radio address. If your software is asking for a CI-V address or a rig ID in hexadecimal, the K4 has nothing to give it — there is no such setting anywhere in the radio. Every address in this manual is an IP address. Give your software a COM port and a baud rate. Which radio profile to pick is a question for that software’s own manual — Elecraft points you there rather than naming one, and the note that the K4 implements a superset of the K3 command set is addressed to developers. Second, remote operation is built in and does not involve a computer at all: a K4 can serve its entire front panel to another K4, to a K4/0 panel, or to a Windows client, over the internet, with the audio and the panadapter going with it. One consequence reaches this page — when you are working a remote radio, some menu entries belong to the radio at the far end and some belong to the panel in front of you, and the ones marked with a small globe at the right of the menu screen are the far end's.

Every switch is two switches, and the manual treats them as two

Elecraft's own convention, printed at the front of the manual: square brackets are a physical switch, angle brackets are a button drawn on the screen, and braces are a knob. Each physical switch carries two legends — the white one is what a tap does and the yellow one is what a hold does — and a hold is any press longer than about half a second. NB and LEVEL are one piece of plastic. So are TUNE and TUNE LP, ATU TUNE and ATU, NTCH and MANUAL, MODE and ALT, RATE and KHZ, SUB and DIV, XMIT and TEST. This means a keystroke on this radio is meaningless without saying which of the two you meant, and it is why every step on this page says tap or hold rather than press. The same applies to the knobs: tapping the little screen buttons beside a knob decides which of that knob's several jobs it is currently doing, and the selected one is boxed in a color.

K4, K4D, and the one that is not shipping yet

Three models share this manual. The basic K4 already does dual receive on the same or different bands. The K4D adds the KRX4 module — a second set of band-pass filters and a second analog-to-digital converter — and with it two things the basic radio cannot do: run the sub receiver on a different antenna, and work in diversity. Elecraft is explicit about both. The K4HD would add a superheterodyne front end with narrow crystal filters, and Elecraft's own manual marks it with the symbol it uses for a feature still in development, with its chapter left as a placeholder. We list the K4 and the K4D here for that reason. A basic K4 upgrades to a K4D by fitting the KRX4, and a K4D to a K4HD by fitting the KHDR4. One thing that catches people after an upgrade: fitting the module is not enough, the matching menu entry has to be enabled as well or the radio reports an error.

What you can do on this radio

Rather do this on your phone, standing at the radio?

The app walks you through the same steps one at a time, on a screen sized for a phone.

Open Radio Rosetta

Set the radio up for FT8 and other digital modes on a K4

Elecraft gives you a straight answer here, which is refreshing: for FT8, JT65 and anything else audio-based, the mode is DATA. Not USB with the compressor turned down — DATA, which does that part for you.

  1. Tap MODE, or tap the mode label next to either VFO.MODEThe screen should show: The mode button group opens.Tapping the label beside a VFO is often quicker, and it makes it obvious which VFO you are about to change.
  2. Tap DATA.touch DATAThe screen should show: The mode identifier beside the VFO reads DATA.Elecraft's own words: DATA can be used for all audio-based data modes, including FT8, the JT modes, PSK31 and 63, MFSK and AFSK. The VFO shows the suppressed-carrier frequency, exactly as it would in SSB, and upper sideband is normal for it. Compression is set to zero internally, which is the part that matters — a compressor running on an FT8 signal is what turns it into splatter.
  3. To set the mode on VFO B instead, tap B SET first, then MODE.B SET›MODEMODE normally acts on VFO A. This is how you reach the other one.

The other three data modes are for different jobs. AFSK is audio like DATA but optimized for RTTY — the VFO shows the mark frequency and lower sideband is normal. FSK is the same but modulates directly, from a data pin, an attached keyboard, or the keyer paddle. PSK is a direct-transmit mode for PSK31 and 63. The last three all work with the radio's own text decoder. A few restrictions worth knowing before you hit them: you cannot run split across two different data modes, the radio will refuse it; LMS noise reduction and certain data modes will not run with the AGC switched off, which is what error 22 is really telling you — the block does not apply to SSNR, and noise reduction itself works in every mode; and in FSK and PSK the keyer paddle only works if text decode is on. If you would rather use plain USB or LSB for digital work, Elecraft's note applies — you will have to set compression to zero yourself, because only DATA and AFSK do it for you. Last, an honest gap: the manual has a chapter headed FT8 configuration and its entire contents are the words to be completed. There is no end-to-end walk-through in this book, so what is on this page is assembled from the pieces that are documented.

Taken from the manufacturer's own manual for this model.

Connect the radio to a computer on a K4

Three serial ports, and no address of any kind. If your software is asking for a CI-V address, the K4 has nothing to give it — that concept does not exist on this radio.

Have these to hand before you start

  • Which of the three serial ports you are using — two virtual ones on the USB cable, and a real nine-pin socket.
  • Nothing else. There is no address, no rig ID, and no hex number to look up.
  1. Tap MENU and scroll with VFO A to Serial USB-PC1: Baud Rate.touch MENU›dial → to the entryThe screen should show: The flat alphabetical menu list.The type B USB socket gives the computer two virtual COM ports, which Elecraft calls USB-PC1 and USB-PC2. The nine-pin socket on the back is a third, real one. All three have their own baud rate, their own auto-info setting and their own DTR and RTS settings.
  2. Tap the padlock to unlock the entry, tap the value field, and turn VFO A. The choices are 4800 up to 115200.touch the padlock›touch the value›dial → the baud rateWatch out. The value is live as you turn it. There is no save and no cancel on this radio, so if you are only looking, note the number before you unlock it. Elecraft does not print which baud rate the radio ships on, so set it deliberately rather than assuming.
  3. Tap the entry's name field first — that hands VFO A back to scrolling the list. Now scroll to the same port's Auto Info entry, tap its padlock, and tap its value field. NOR is the default and means the radio only answers when spoken to.touch the entry name›dial → to Auto Info›touch the padlock›touch the value›dial → NOR or AUTO1On AUTO1 the radio volunteers an IF response whenever you change the VFO, the mode or the RIT. Some logging software wants that and some software gets confused by it arriving mid-conversation. NOR first, AUTO1 only if your program asks for it.
  4. Tap the name field again to resume scrolling, go to the same port's DTR entry, unlock it and tap its value. The DTR entry decides what that control line does — off, PTT, key, or FSK. RTS offers the same list without FSK.touch the entry name›dial → to DTR›touch the padlock›touch the value›dial → PTT, KEY or FSKWatch out. That asymmetry is real and the radio enforces it: FSK keying over a serial port can only be done on DTR, never on RTS, and asking for it on RTS gets you an error. Also worth knowing when things go wrong — if the transmit lamp is on all the time, a stuck DTR or RTS line configured as PTT is the first thing Elecraft tells you to check.
  5. For the audio side, tap MAIN RX then LINE OUT for receive levels, and TX then LINE IN for transmit.touch MAIN RX›touch LINE OUT›touch TX›touch LINE INThe same USB cable carries a sound card as well as the control ports, so one lead does control, audio in and audio out.

Two things that will save you an evening. Plugging anything new into the computer, the K4 included, can shuffle the COM port numbers around — Elecraft says so explicitly, and it is the usual reason a setup that worked yesterday does not today. And Windows does not show the sound input level correctly for this radio; the manual says so in three separate places and tells you to trust what WSJT or MMTTY shows instead. For the command set itself, the K4 implements a large superset of the K3 and K3S commands, and the actual list is in a separate programmer's reference rather than this manual — Elecraft names HRD, N1MM, WinTest, Writelog and Win4K4Suite as things people run, and then points you at those programs’ own manuals for the setup rather than giving per-program settings. So which profile to pick is a question for your software’s documentation, not this one — the superset relationship is addressed to developers, not offered as configuration advice.

Taken from the manufacturer's own manual for this model.

Set the drive level for digital modes on a K4

Elecraft gives an actual target, and it is a different one from the voice target on the same meter. Just below the 5 mark on the ALC bargraph — not between 5 and 7, which is what you use for a microphone.

  1. Tap TX, then LINE IN. Choose SOUNDCARD for audio arriving over the USB cable, or LINE IN for the analog jack.touch TX›touch LINE INThe screen should show: The line in setup, with a level for each source.The two sources keep separate levels, so setting one up does not disturb the other.
  2. Hold TEST before you start. Now you can key up and set levels without anything going on the air.hold TESTThe screen should show: The TX icon changes to read TX Test.Elecraft recommends this for the whole adjustment, and notes that it does not change your ALC or compression readings. There is no reason to do this part on a live antenna.
  3. Transmit from your software and bring the level up until the ALC bargraph sits just below the 5 mark.key the transmitter from your software›dial → the line in levelThe screen should show: The S meter is replaced by transmit bargraphs — power, SWR and ALC. The fourth, compression, only appears in SSB and ESSB.Just below 5 is Elecraft's figure for modes where low intermodulation matters, and FT8 is the example they name. If you are coming from a K3, their note is worth reading: the K4's bargraphs have twice as many segments for the same level, so the K3's old advice of four bars would be eight here — and it is easier to just watch for the 5.
  4. Hold TEST again to come out of test mode.hold TESTWatch out. Easy to forget, and the symptom is a radio that appears to be transmitting normally with nothing coming out.
  5. For power, tap the lower screen button beside the XMTR knob until PWR is the highlighted one, then turn the knob.touch PWR›dial → XMTRThe screen should show: PWR boxed in orange beside the knob.Watch out. Tapping the XMTR knob itself also cycles which of its jobs is selected. Check what is highlighted before you turn it, because in a voice mode the same knob is microphone gain.

Three traps around power on this radio. If power will not go above 10 watts, the KPA4 module needs enabling in the menu — fitting it is not enough, and the error message says so. If there is no output at all, check that the transverter output test in the menu is not on, because it silently sends all your RF to a different jack and rescales the power display into milliwatts. And by default one power setting covers every band; set Per-Band Power on if you would rather each band remembered its own, which is worth doing if one of your antennas has a tuner on it. One more, for anyone using USB or LSB for data rather than DATA mode: compression is not zeroed for you there, and any non-zero compression setting brings in controlled-envelope SSB, and at maximum compression — CMP 30 — Elecraft warns that average talk power can rise by as much as 8 dB, including into an amplifier that was not expecting it.

Taken from the manufacturer's own manual for this model.

Narrow the filter to shut out the station next door on a K4

One knob, four jobs, and two screen buttons that decide which two of the four are live. It sounds fiddly and takes about a minute to become automatic.

  1. Tap the upper screen button beside the FILTER knob until BW is highlighted. Tapping it again swaps it to HI-CUT.touch BWThe screen should show: The selected label is boxed in a color.The upper button holds bandwidth and high cut; the lower one holds shift and low cut. You work either as a width-and-center pair or as a pair of cutoffs, whichever suits what you are trying to get rid of.
  2. Turn the FILTER knob.dial → FILTERThe screen should show: The filter graphic beside the S meter changes shape as you turn.Watch out. Look at the color of the button box before you turn. Blue means you are adjusting the main receiver and green means the sub. Tapping B SET or SUB RX first is how you aim at the sub deliberately.
  3. Holding the FILTER knob puts the passband back to the nominal width for whatever mode you are in.hold FILTERThe screen should show: Two small wings appear on either side of the filter graphic.This is the escape hatch when you have narrowed yourself into a corner and cannot hear anything.
  4. FIL steps through three saved presets per mode — wide, medium and narrow.FILThe screen should show: The preset number under the filter graphic.Watch out. You can also tap the filter graphic itself to cycle them. Which direction it cycles is not something we will assert: Elecraft's manual gives the order as 3 2 1 in one place and 1 2 3 in another. Watch the number.

One menu entry worth knowing about if you work CW. The four narrowest CW filters — 50, 100, 150 and 200 Hz — can be given much steeper skirts by the infinite-impulse-response option, which ships on. Above about 25 words a minute, though, Elecraft warns that the narrowest two add enough delay to hurt your copy, and suggests either turning the option off or staying at 150 and wider. And a detail that only matters when you are down at 50 Hz: the filter centers move in 50 Hz steps while the sidetone pitch moves in 10, so picking a sidetone that is a multiple of 50 lines the two up properly. Being honest about a gap: this manual gives no numbers for the filter range or for what the three presets actually are in each mode. The only receive bandwidth figures printed anywhere are those four CW filters and the audio peaking filter's 30, 50 and 150 Hz. Transmit is a different matter — the SSB transmit bandwidth has a default of 2.9 kHz and ESSB 4.0 kHz, both under TX. If you have narrowed down and gone deaf, Elecraft lists too narrow a filter as one of the standard causes of no received signal — hold the knob and start again.

Taken from the manufacturer's own manual for this model.

Turn on noise reduction on a K4

Two genuinely different algorithms, and the choice between them matters more than the level does.

  1. Tap NR to switch it on or off.NRThe screen should show: NR appears in the icon row under the S meter.
  2. Hold the same switch — its yellow legend is ADJ — to open the settings.hold ADJThe screen should show: The noise reduction controls, with a button that reads LMS or SSNR.
  3. Tap the LMS and SSNR button to choose the algorithm, then set the level.touch LMS or SSNR›dial → the levelLMS is the default and runs 1 to 10. SSNR is spectral subtraction and runs 1 to 20. Elecraft's guidance is that SSNR is optimized for voice, while on CW and data you will often find LMS preserves a weak or tightly spaced signal better. Higher settings remove more noise and do more damage to how a voice sounds. The choice is saved per band and per VFO.

Two interlocks on this radio that are worth knowing before they surprise you, because the error messages are terse. With LMS noise reduction running you cannot switch the AGC off — Elecraft's reason is that the algorithm's gain would run away without it, and the restriction does not apply to SSNR. And in the other direction, error 22 reads "NR not allowed in DATA modes or if AGC is off" — but what it actually says underneath is that LMS noise reduction and certain data modes cannot be used with AGC turned off, and that turning AGC on is the fix. So the interlock is AGC, not the data modes. Both types of noise reduction can be used in all modes, and Elecraft's mode-specific advice is already in the step above. If you reach for NR while chasing a weak FT8 signal and nothing happens, check whether you have AGC off. Elecraft's own alternative is worth taking seriously: narrowing the filter, or using the audio peaking filter, often does more for a weak signal than noise reduction does, and can be used alongside it. One last thing — if your audio has gone quiet and you cannot work out why, noise reduction left on is on Elecraft's own list of causes.

Taken from the manufacturer's own manual for this model.

Turn on the noise blanker on a K4

There are two noise blankers on this radio and they do completely different things. One cleans up what you hear. The other cleans up what you see, and touching the wrong one is the commonest confusion here.

  1. Tap NB to switch the receiver's blanker on or off.NBThe screen should show: NB appears in the icon row under the S meter.
  2. Hold the same switch — the yellow legend is LEVEL — to bring up its controls: on or off, the filtering mode, and the level.hold LEVELElecraft's advice is the same as for every blanker: use the lowest setting that works. A blanker turned up hard manufactures intermodulation between strong signals that was not there before.
  3. If you hear pumping or an odd modulation with the blanker on, change the NB filter from NONE to NARROW or WIDE.touch the NB filter modeThat filter removes interference ahead of the blanker, so the blanker is not trying to chop up a strong signal alongside the noise. NONE is the default, and this is the single most useful thing on this page — most people never find it. Expect the right level to be different once the filter is engaged.
  4. On a really noisy band, switch the preamp off and try the attenuator on, then judge the blanker again.PRE›ATTNElecraft's own tip, and it is counterintuitive enough to be worth repeating: reducing front-end gain keeps the noise below the AGC threshold, which makes the difference between the blanker on and off far more audible.

The other blanker lives under DISPLAY and then NB, and it affects only the panadapter — it stops a noisy band from filling the waterfall with hash. It has its own threshold and an AUTO setting that follows the receiver's blanker. Two letters, two controls, no connection between them in what you hear. And one thing that is neither blanker: there is a separate pulse rejector inside the AGC, and if your S meter or the signal is being modulated oddly with the noise blanker off, Elecraft's suggestion is to turn the AGC noise pulse reject menu entry off, or use the blanker at a low setting instead.

Taken from the manufacturer's own manual for this model.

Notch out a whistle or a carrier on a K4

Both kinds, on one switch, and they can run at the same time. The thing to get right is that they cover different modes.

  1. Tap NTCH for the automatic notch.NTCHThe screen should show: NTCH-A in the icon row under the S meter.Watch out. Speech modes only. In CW this one does nothing at all, and the radio will tell you the control does not apply rather than explaining why.
  2. Hold the same switch for the manual notch.hold MANUALThe screen should show: NTCH-M, or NTCH-A/M if the automatic one is on as well.Manual notch covers CW and SSB. Lay the two together and you get four cases: in SSB you can have both, and if you do the icon reads NTCH-A/M; in AM and FM, which are speech modes, you get the automatic one only; in CW you get the manual one only; and in the data modes neither is documented as applying.
  3. Tune the notch with the VFO A knob until the tone disappears.dial → VFO AWatch out. Read that again: while you are setting the notch, the VFO A knob is the notch control and not the frequency control. Elecraft does not print how you hand the knob back to tuning, so we are not going to invent a keystroke for it. Expect to have to work that out on your own radio, and do it before you need it in a pileup.

There is no depth or width adjustment for either notch and no printed default state for them. Elecraft mentions one extra use for the automatic notch that is worth knowing: it is a decent way of getting rid of a birdie — one of the radio's own internally generated spurious carriers — in a voice mode.

Taken from the manufacturer's own manual for this model.

Work a DX station that is running split on a K4

A hold, not a tap. And the radio then tells you it is in split in four separate ways, one of which is the meters physically moving to the other side of the screen.

Have these to hand before you start

  • The frequency the DX station is transmitting on.
  • Where he is listening.
  1. Set VFO A to where the DX station is transmitting — the frequency you want to listen to.dial → VFO A
  2. Copy it across with A>B, then tune VFO B to where you will transmit.A>B›dial → VFO BVFO B is the transmit VFO once split is on.
  3. Hold SPLIT.hold SPLITThe screen should show: Four things change at once. The TX icon's arrow moves to point at VFO B, the SPLIT ON icon lights, the yellow delta-F lamp above the VFO A knob comes on, and the transmit bargraphs move to the right-hand side of the screen.Watch out. It is a hold. The manual's procedural section says hold and its summary list just says the switch enters split without saying which gesture, so follow the procedure. That fourth indication — the meters moving across — is deliberate: Elecraft describes it as a clear reminder to the operator about whether split is in effect.
  4. Hold REV to swap the two while you hold it, which is how you check your own transmit frequency when the sub receiver is off.hold REVIt reverts the moment you let go, so it is hard to leave yourself somewhere unexpected.

Two honest gaps and three refusals. Elecraft never prints how to turn split off, so we are not going to guess — try it on a quiet band. And the manual never sets out, in one place, which of the five VFO legends sit on which of the three physical switches — the pairings on this page are the ones it spells out inside procedures, not ones we worked out from the panel photograph. The refusals: cross-band split only works if the receivers are on receive-only antennas or the transmit band is higher than the receive band; cross-mode split is blocked outright between two data modes; and if CW suddenly will not transmit, Elecraft's own troubleshooting suggests you may be in split with VFO B set to a voice or data mode. Finally, and this is the one that bites: split survives a power cycle. That is precisely why the radio has a startup macro — Elecraft's own example of what people put in it is turning split off, because many operators prefer it to default to off.

Taken from the manufacturer's own manual for this model.

Save a frequency to a memory channel on a K4

Two hundred general memories and four quick ones per band. What is unusual is that a memory here holds both VFOs, not one — which is why the scan feature can use a memory as a pair of band edges.

  1. Set both VFOs and both modes the way you want them kept.dial → the frequencies›MODE
  2. Tap STORE. The memory selector opens.STOREThe screen should show: The frequency memory window.Nothing has been written yet. STORE only opens the window.
  3. Turn VFO A to the memory number you want.dial → to a memory numberThe screen should show: The highlighted entry, showing whatever is already in it.
  4. Tap STO on the screen to write it, then the dismiss arrow to leave.touch STO›touch the dismiss arrowWatch out. Two different things are both called store here. STORE in square brackets is the physical switch that opens the window; STO in the window is the touch button that actually writes. Only the second one saves anything.

Recall is the mirror image: tap RCL, scroll, tap the RCL button on screen. Tapping the megahertz digits of either VFO gets you there too. While the on-screen RCL button is lit you can actively scroll through the frequency memories without having to recall each one, which saves a lot of tapping — tap it again to turn active scroll off. Two things to be careful of. Erasing is a single tap of CLR on the highlighted entry, with no confirmation documented anywhere. And the M1 to M4 keys only mean quick memory in the moment after you have tapped STORE or RCL — at any other time, in CW, PSK or FSK they send a message, and in a voice mode they play a recording. If you are in the habit of reaching for M1, be sure which of those three things you are about to do. Worth doing before any of this: tap Fn and hold BACKUP with a flash drive in one of the USB sockets, and the radio will write your memories, your configuration, your macros and your messages to it.

Taken from the manufacturer's own manual for this model.

Run the antenna tuner on a K4

The tuner is the KAT4 module and it is an option, not standard — and there is a nice tell for whether you have one. If the radio has only one antenna socket, there is no tuner in it. Three sockets means the module is fitted.

  1. If the tuner has just been fitted, enable it in the menu first — scroll to KAT4 ATU Option, tap its padlock, then tap the value field.touch MENU›dial → to KAT4 ATU Option›touch the padlock›touch the valueThe screen should show: KAT4 ATU Option.Watch out. Elecraft's manual is inconsistent about what value to set. The menu listing says AUTO; two of the radio's own error messages say ENABLED. We are reporting both rather than picking one — set it to whichever your radio actually offers.
  2. Hold ATU to put the tuner in line. Holding it again bypasses it.hold ATUThe screen should show: An orange ATU icon in the transmit icon area.Watch out. If you try to tune while it is bypassed the radio refuses and tells you to hold this switch first. It is a hold, not a tap — the tap on the same switch is the tune.
  3. Tap ATU TUNE to find a match.ATU TUNEThe screen should show: The relays cycle for one to four seconds.It tunes at 5 to 10 watts, which is gentle, and stops on its own. The result is stored against that band and that antenna — up to 32 solutions per combination, so the radio learns your antenna system as you use it.
  4. If it did not get below about 2 to 1, tap ATU TUNE again within five seconds.ATU TUNEA second tap inside that window makes it try more relay combinations, which is what narrow-banded antennas need. That extended search can take up to ten seconds.

Once you have tuned a band at a few points, retuning is rarely needed even on a narrow antenna — the radio checks the stored settings closest to your frequency every time you transmit, which is why you sometimes hear relays click for a moment after moving the dial. Three things worth knowing. Elecraft's own suggestion for not annoying anyone while you tune is to use XIT to shift off frequency first. The tuner is in the receive path as well, and its transmit-receive switch has a high-pass filter in it, so anything below about 1 MHz is attenuated when you are receiving on the transmit antenna. And do not confuse the two tune switches: TUNE puts out a carrier at your set power for testing and for driving external gear, while ATU TUNE runs the internal match at 5 to 10 watts. Getting those the wrong way round at 100 watts into an external tuner is a hardware risk rather than an inconvenience. There is also a low-power TUNE on a hold of that switch, with its own power level in the menu, specifically for amplifiers and external tuners that want a particular drive.

Taken from the manufacturer's own manual for this model.

Set the CW keyer speed and weight on a K4

It is on the XMTR knob, and which of that knob's jobs is live depends on which little screen button beside it is boxed in orange.

  1. Get into CW first — press MODE and touch CW. The XMTR knob's buttons offer different things in different modes.MODE›touch CW
  2. Tap the upper screen button beside the XMTR knob until WPM is highlighted. Tapping it again swaps to the sidetone pitch.touch WPMThe screen should show: WPM boxed in orange.Watch out. In a voice mode those same two labels are microphone gain and compression. Turning the knob without checking what is boxed is how people end up with their mic gain at maximum.
  3. Turn the XMTR knob to set the speed.dial → XMTRElecraft expects most CW operators to just leave WPM as the selected function and reach for the others occasionally. Tapping the knob itself is another way to cycle which one is live.

The rest of the keyer is under TX: the paddle button swaps dot and dash, the iambic button picks mode A or B with A as the default, and the weight button sets the dot to space ratio, where Elecraft suggests 1.15 to 1.20 for most people. Two warnings from the manual that are easy to trip over. With VOX off the paddle does not put the radio into transmit at all — you have to tap XMIT, use the microphone PTT, or bring in a foot switch on the PTT IN jack. Hit-the-key transmit needs VOX on. The other way to key and send nothing is TX TEST mode, held on the TEST switch: the transmitter and the amplifier key line both behave and no RF comes out, which is exactly what you want for practicing and exactly what will confuse you if you left it on. And do not try to fix keyer timing with an amplifier delay setting. There are two of those entries — TX DLY, Key Out to RF Out, which sets the gap between keying the amplifier and the RF starting, and TX DLY, Unkey to Receive, which sets the gap on key-up to stop clicks and pops from a slow amplifier relay. Elecraft’s warning attaches to the first one: it is for external amplifiers, not a way to compensate for a low weight setting, and large values may interact with CW timing at faster speeds. The second entry carries a note of its own — values of 0 to 15 still allow QSK, while 16 to 60 stop affecting CW timing at any speed but no longer allow full break-in even with QSK switched on. We are not going to publish a speed range or a factory default for the keyer, because this manual gives neither.

Taken from the manufacturer's own manual for this model.

Reset the menu to factory settings on a K4

This is the one place on the K4 where we have to be straight with you: the whole-radio reset exists, the manual mentions it twice as the fix for a problem, and the manual never says how to do it. So here is everything that is documented, in order from gentlest upward.

  1. To put one menu entry back: find it, and tap NORM.touch MENU›dial → to the entry›touch NORMThe screen should show: NORM lights up when the entry is already at its factory value.This is the everyday fix. If you have changed one thing and cannot remember what it was, NORM on that entry undoes it. Note that NORM goes to the factory value, not to what you had before — there is no undo on this radio, only a default.
  2. To put the filter back: hold the FILTER knob. That restores the nominal passband for the mode you are in.hold FILTERThe screen should show: Wings appear on either side of the filter graphic.
  3. To put the whole radio back to how you had it: plug a flash drive into one of the USB A sockets, tap Fn, and hold BACKUP.touch Fn›hold BACKUPThe screen should show: The backup and restore utility.Six categories — the general configuration, the frequency memories, the PF key and K-Pod macros, the CW, PSK and FSK messages, the voice recordings, and the diagnostic logs. This is the only whole-radio restore the manual actually documents, and it restores your settings rather than the factory's. Do it now, while everything works, and the rest of this page stops mattering.
  4. If the radio comes up wrong every single time you switch it on, hold REV while you power up.hold REV›POWERThat bypasses the startup macro. A startup macro can override the radio's own settings at every boot — turning split off, clearing RIT, and so on — and if somebody has put something unhelpful in it, this is how you get one clean boot to go and fix it.

About the full reset. Elecraft's troubleshooting section says to try initializing parameters when software behavior is generally wrong, and error 21 — a band data error — says the same thing. The phrase is used as though you already know the procedure, and this manual never gives it: there is no menu entry, no switch, no power-on combination, and nothing in the Fn list that does it. We have looked at every page. So rather than publishing a guess at a keystroke that could wipe your radio, here is the honest answer: the K4 carries a searchable copy of its own documentation — tap the question mark at the lower left and search it — and Elecraft's support is unusually good at answering this kind of question directly. Back up to a flash drive first either way.

Taken from the manufacturer's own manual for this model.

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