OnAllBands is featuring a raft of new products available at DXEngineering.com in the months ahead. As a reminder, you can always visit the website to check on the latest offerings, including discounted “open box” and “scratch and dent” items added every day, by clicking “What’s New” on the website’s menu bar.
Today, OnAllBands is pleased to introduce two new performance-enhancing products:
DX Engineering KD9SV Keying Relay
This unique and useful device takes the place of a traditional keying line buffer between a transceiver and an amplifier. Inspired by the original KD9SV Keying Relay, the new model provides a straightforward way to ensure that your sensitive transceiver or electronic keying circuit is isolated and protected, along with offering other benefits.
The DX Engineering KD9SV Keying Relay (DXE-SV-KR) makes a great replacement for the popular Ameritron ARB-704 Amplifier Transceiver Keying Interface (without the specialized “multi” plug transceiver cables or AC switching). MFJ, owner of the Ameritron product line, ceased production of the ARB-704 after the company closed shop in May 2024.
What do hams say? John, W4NU, was succinct in giving praise in his five-star review of the KD9SV Keying Relay:
“Great product!” he wrote.
This high-speed, solid-state interface is designed to protect transceiver keying circuits from potential damage by amplifier relays. Transceiver low-voltage keying circuits handle only a few milliamperes (mA), but some “modern” amplifier relays require over 150 mA at 12 VDC. High voltage and high current amplifier keying relays were common in amplifiers made between 1950 and 1980. The DXE-SV-KR can safely key all DC amplifier relays, including older relays and keying inputs that operate at high voltage, typically -100 or +110 VDC.
“The new DX Engineering KD9SV Keying Relay has an odd name because it isn’t a mechanical device,” explains Rod Ehrhart, K8RR, DX Engineering technical support specialist. “The new DXE-SV-KR is totally ‘solid state’ silent. And even though it looks like the DXE Keyline Series with diode-protected pass-through ‘ground-on-transmit’ keying and typical RCA phono keying connectors, the DXE-SV-KR is completely different.
“This ‘active’ amplifier keying buffer device features an optically isolated, very low current ground-on-transmit PTT input. When it is keyed, it simultaneously closes TWO completely isolated high-voltage capable ground-on-transmit PTT Output connectors. This device behaves like a normally open (N.O.) DPST relay with two isolated dry contacts. But it has the convenience of RCA phono connectors.”
Other features and benefits:
- Each Output connector is capable of handling up to +/- 450VDC at up to 500mA.
- It’s standard 2.1mm 13.8VDC only requires 2mA to key the input. It can be operated for months on battery power!
- The optically isolated PTT Input is safe for any transceiver’s amplifier keying circuit or any other “ground-on- transmit” PTT keying accessory.
- The DXE-SV-KR behaves like a normally open (N.O.) Double-Pole, Single-Throw (DPST) relay, without the high current draw or back pulse of a relay coil.
- Built in a convenient enclosure with RCA phono jacks, the DXE-SV-KR is also QSK capable for keying any amplifier that supports high-speed CW keying, typically a solid-state amplifier (or specially equipped tube amplifier) with a high-speed circuit for “Key In” PTT.
- The unit may also be used to isolate a straight key or a solid state electronic keyer connection from any CW key input. It will provide crucial protection and safety on high voltage CW key jacks and circuits common on old tube-type transmitters and transceivers.
- This device’s high-speed capability also provides relay debouncing, or it can be used as a remote high-voltage DC switch.
- The DXE-SV-KR Keying Relay is an upgrade over the original solid-state KD9SV Keying Relay model that had just one PTT output and an RCA power connector.
For more details and to order the KD9SV Keying Relay, visit DXEngineering.com.
In the video below, watch Tim Duffy, K3LR, DX Engineering CEO, interview Rod, K8RR, about the KD9SV Keying Relay (starting at 5:28) and the Toptek Power Amplifier Remote Control Panel for use with the Toptek PA-350V 144 MHz amplifier and Toptek PA-150U 430 MHz amplifier. This user interface duplicates the LCD display and push-button keypad operation of the front panel of these amplifiers.
