Kenwood TK-250

The Kenwood TK-250 is a model number that landed on two completely different products, so the page starts there. The better-documented one is a VHF handheld transceiver. It's a commercial two-way radio, not hi-fi. The Kenwood service manual describes a VHF/FM hand-held transceiver built to cover 150 to 174 MHz, with a receiver, transmitter, PLL frequency synthesizer, power supply, control unit and display unit. The manual also lists a second version, the K2/M2 (Type 2) set, which covers 136-150 MHz with a 45.05 MHz first IF and a 45.505 MHz local oscillator. So the radio exists in at least two band splits. The 136-174 MHz figure that circulates is the two of them added together.

The manual makes clear this was a computer-programmed commercial set, not a knob-and-crystal handheld. Channels are written into an E2PROM using a PC, the KPG-22 programming interface cable (a 25-pin D-sub that converts RS-232C levels to TTL), and the KPG-23D software, which shipped on both 5¼" and 3½" disks. The radio enters PC mode when you hold the [LAMP] and [LO] keys while switching on. The display shows "-PC-", and a red LED indicates transmit, green receive. There's also a clone mode for copying one radio's E2PROM to another over the optional KCT-8 cable. It takes about forty seconds and ends with "END" on the transmitting side's LCD. The manual is explicit that the TK-250/350 cannot be cloned with any other model, and that VHF, UHF and IF settings must match before data is written.

The manual's adjustment section gives the standard supply voltage as 7.5V. The set is designed to run from a battery pack, and the KNB-12 (7.2V Ni-MH) is the one usually cited, with aftermarket replacements sold at 1,200 and 1,800 mAh. Beyond that, the record thins out. No production years, original retail price, dimensions, weight or channel count are documented. The TK-250G variant is described as a 5-watt set operating on MURS frequencies (151.820, 151.880, 154.520 and 154.580 MHz), and the same manual covers the sibling TK-350.

The second product is a solid-state stereo integrated amplifier, also sold as the TK-250, and as the TK-250U, which listings group with a TK-350U. One seller describes it as Japanese-built, roughly 1967, from the tube-to-transistor transition, and quotes 20 watts per channel. That power figure appears in only one place and shouldn't be treated as settled. No service literature, frequency response, distortion figures or input list survive for the amplifier. No source resolves whether Kenwood really used the same number twice or the databases simply collided.

Known facts, radio version:

VHF/FM handheld transceiver; Type 1 (K, M, T, E) covers 150–174 MHz, Type 2 (K2, M2) covers 136–150 MHz
PLL synthesizer, E2PROM channel memory, LCD display
Programmed via KPG-22 cable and KPG-23D software (PC mode); cloned via KCT-8
Standard supply voltage 7.5V; KNB-12 7.2V Ni-MH battery pack
TK-250G variant: 5W, MURS frequencies
Manual shared with TK-350