PA50WV VHF 2M
VHF channel: 50 W transmit +19.5 dB receive
The PA50WV 50W VHF power amplifier (hereinafter referred to as the "Amplifier") for the 2M band is designed for linear amplification of high-frequency signals. Externally, the amplifier consists of a SunSDR2 PRO transceiver housing and a heatsink and cooler from the SunSDR2 DX transceiver.
This amplifier will be of interest to operators making long-distance contacts on the 2 m amateur band. One possible application is installation in a vehicle together with a SunSDR2 PRO transceiver.
A Mitsubishi RA60H1317M amplifier module is used to deliver 50 W of VHF output power. Active broadband components eliminate the need for adjustment or tuning throughout the operating frequency range. Active cooling allows continuous-carrier operation for extended periods at full output power. The amplifier uses a conventional single-ended circuit and supports all modulation modes.
Features:
50 W
PA50WV provides clean signal amplification up to 50 W over the 136–174 MHz range.
The amplifier can operate continuously for extended periods, including in digital modes.
Two input levels
The input-power setting can be switched between 1 W and 5 W.
Compact size
The amplifier measures 185 × 165 × 83 mm including the cooling module and weighs 1.7 kg, making it suitable for DXpeditions.
Built-in LNA
To improve reception, the amplifier uses a low-noise amplifier with a gain of +19.5 dB. It is enabled by the “LNA” button on the front panel and operates only on receive: power to the LNA is removed automatically when switching to transmit.
What the LNA delivers in practice
The measurement was made with a SunSDR2 PRO transceiver at 145.1 MHz in CW, with a 500 Hz receiver bandwidth and an input signal level of −110 dBm.
LNA off: signal −112.2 dBm, noise −122.4 dBm
LNA on: signal −93.9 dBm, noise −120.3 dBm
The signal increased by 18.3 dB, while the receiver noise increased by only 2.1 dB.
The signal-to-noise ratio improved by 16.2 dB: a station that was barely intelligible can now be received clearly.
The improvement depends on the antenna, feed line and noise conditions at the operating location: the lower the receiver's own noise, the less an external preamplifier will contribute. These figures are the result of a specific measurement, not a guaranteed specification.
Transmit control
The amplifier switches to transmit in response to an external control signal from the transceiver through the “TX” connector. PA50WV has no RF detector: an input signal alone does not switch it to transmit, so the transceiver must provide a PTT control output.
Output power and drive
The “Pin” button selects an input level of 1 W or 5 W; nominal output power is the same in both settings: 50 W. The amplifier is linear, so output power follows input power: in the 5 W setting, an input of 2.5 W produces approximately half the output power. There is no separate power control on the enclosure and ALC is not used; power is set in the transceiver.
Important. Set the drive-power limit in the “Power correction” menu of the transceiver control software. This sets the maximum output level in the firmware and strictly limits spikes that could damage the amplifier. Never apply an input level above the selected setting.
