The NRV4C is a Remote Digital PLL Generated VFO for the Drake 4 Line and is compatible with the Drake R-4C / T-4XC / T-4X / R-4A and R-4B combinations. The VFO has CAT control cababilities which allow the "Twins" to be controlled by PC applications such as Logging Programs and Rig Control Programs such as Ham Radio Deluxe. The NRV4C emulates the Kenwood TS-480 CAT protocol and will function with any application that supports that radio. There are two VFO's available. One controls the receive frequency and the other the transmit frequency. The R-4C receiver can listen on the TX frequency which is useful for Split Frequency operation. The NRV4C is connected to the R-4C by a Band Data cable which plugs into the crystal sockets of the 5 standard band crystals normally supplied with the radio. These crystals are removed to allow the cable installation. Once the NRV4C is installed on the radio full HF coverage is available (1.5 to 30 MHz minus the 5.6 MHz area around the IF frequency range) without the use of any crystals. The NRV4C will follow the band switch on the R-4C and display it's position on the LCD display of the NRV4C. Only frequencies within the allowable band switch range will be allowed to be programmed into the VFO.
In addition to the VFO function there is also a Keyer for CW. The keyer is built around the K1EL WinKey3 chip and uses all the fucntions of that device including a USB port for control by a PC application which supports the WinKeyer mode. There are 5 CW memories which can be programmed and recalled from front panel switches. There is also a TUNE switch provided on the front panel to allow for easy CW tuneup of the transmitter. This removes the need to use the TUNE function on the T-4X/C and then having to readjust power level for normal operation.
For SSB operation there is a VOGAD type speech compressor to enhance the mic audio delivered to the transmitter. Gain and Compression controls are provided on the front panel.
The NRV4C also has a built in Sound Card which can be used for Digital Mode operation. Any mode that uses audio tones between the reciever and transmitter can be used with the Sound Card. The Sound Card interfaces to the PC via a USB port on the back of the NRV4C. There are RX and TX Gain Controls on the front panel to allow easy adjustment of audio levels without having to access the PC sliders.
To allow the Twins to function like a modern transceiver the NRV4C has a buit in Panadapter which is designed to be used with Ham Radio Deluxe and HDSDR. The CAT port on the VFO allows this combination to provide "point and click" frequency tuning of the station off of the HDSDR spectral display using a mouse. The HRD Logging program can be used with this combination or another logging program can be used by interfacing to HRD via it's 3rd Party COM Port. The use of the NRV4C with HRD and HDSDR plus a logging program allow state of the art control of the Drake Twins while still providing the vintage sound and feel of the Drake equipment.
Lastly, there is a built in front firing speaker which can be connected to the R-4C output. It is a high quality device with a frequency range of 100Hz to 20 KHz and is capable of handling up to 30W of audio power.