Elecraft K4 (K4 / K4D / K4HD)
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| Frequency | 160-6 m transmit, 100 kHz-54 MHz receive |
| TX power | 100 W (100 W internal) |
| Modes | SSB, CW, AM, FM, DATA |
| Weight | 4.5 kg (9.9 lb) |
| Connector | SO-239 |
| mic | Elecraft-standard 8-pin round, K3/K3S-compatible (MH4 mic; rear panel has a separate electret mic input) |
| key | 3.5mm stereo (tip=dit, ring=dah) |
| antenna | SO-239 |
| usb | USB (audio codec + CAT control) |
| power req | 13.8VDC or internal battery (model dependent) |
The SDR for operators who kept their reflexes: direct-sampling performance and a real waterfall without surrendering the tactile front panel, plus an upgrade ladder (D for diversity, HD for superhet-grade survival) that turns buyer's remorse into a parts order. Elecraft's firmware-forever culture and human-answered support remain the brand's moat.
Flagship pricing that climbs the ladder fast, a single 7-inch screen where the competition offers bigger glass, and the modular promise means the base K4 ships without the diversity hardware the K3S crowd considers the point - budget the D from the start. Production cadence is boutique: waits happen.
The thinking station's current flagship: K3-dynasty receive philosophy, modern direct-sampling guts, knobs where knobs belong. Buy the D if low-band diversity is your religion; buy anything else only after touching this one's front panel.
The K4 is Elecraft answering its own legend: how do you succeed the K3S - a decade atop the receiver rankings - without abandoning what made it beloved? The answer is a direct-sampling SDR wearing a traditionalist's front panel: a 7-inch touch display finally brings the waterfall the K3 era lacked, while the per-function knobs and buttons survive intact for the operators whose hands think faster than menus. Underneath, the crystal filters are gone entirely - filtering is mathematics now - with dual watch across a 100 kHz-to-54 MHz receive range, five selectable receive RF sources, and 100 watts out from 160 through 6 meters.
The model ladder is the company's modularity made strategy: the base K4 runs a single ADC; the K4D adds a second converter and second bandpass set, restoring the true two-antenna DIVERSITY reception that made the K3's subreceiver famous; and the K4HD bolts the KHDR4 dual-superhet module - two crystal filters per receive section - ahead of the sampling for the most hostile RF environments: multi-multi contest stations, co-located transmitters, anywhere even good ADCs want a bodyguard. (The HD rung remains a no-deposit, Price-TBD pre-order as of this writing - coming soon since launch-era, a boutique-cadence honesty worth knowing.) Every shipping rung installs as boards, not trade-ins, and the firmware cadence has added features steadily since launch in the house tradition of radios that improve while you own them.
Its market position is precise: against the screen-first SDR school it argues for tactile immediacy; against the Japanese flagships it argues receiver philosophy and a support culture where humans answer; against its own ancestor it argues waterfall, sampling, and headroom. The price ladder climbs accordingly - the K4D commands a healthy premium over the factory-built K4 - and the diversity-minded should budget the D variant from the start - the base radio ships without the second ear that K-line devotees consider the family birthright.