DX Engineering DXE-TVSU-1B, Руководство пользователя

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"hang-time" delay on the CW, PPT and AMP lines, along with the RADIO input from the
transceiver, allows time for the transmitter output power to subside before switching back to
receive.
Features

Control timing of PTT turn-on, hang delay of PTT, amplifier hang delay, external
antenna relay hang delay and turn-on delay of auxiliary output

Dip switch settable delays of 0-30 milliseconds in 2 millisecond steps

Sidetone generator that follows input of keyer or hand key not transmitter

Sidetone pitch can be programmed from 300 to 1000 Hz in 50 Hz steps, front panel
headphone jack with adjustable volume

Supports CW full break in

Can control external power to our Active Receive Antennas and permit operation in
closer proximity to transmit antennas
Typical Applications
Compensating for Slow Power Amplifier Relays
Occasionally, CW signals truncate or miss the first part of a Morse code element. A "W" might
become an "M", a "K" might become a "U", and many other similar changes might occur. Even if
the leading element is just slightly shortened, it can cause problems in rapid exchanges or when
signals are weak. The
TVSU-1B will delay the CW signal to the transmitter, allowing even the
slowest relays to fully transfer before the radio transmits. This sequencer will completely eliminate
truncating of leading elements by slow external relays, as well as extend equipment life.
Protecting Receiving Equipment
Receiving equipment must be completely disabled before transmitter RF appears. The very fast
relays used in the DX Engineering
AVA-2 series of receiving amplifiers, used for the active
antennas, require 2 ms of switching time. Some radios provide adequate time at the linear amplifier
keying port, but many do not. Because of this, we recommend using the
TVSU-1B in all receiving
systems using the Active Antennas, such as a Receive Four Square or phased vertical system. The
TVSU-1B will turn off the receiving antennas before allowing the transmitter to come on, and only
turn the receiving antenna back on after the transmitting signal is gone.
The
TVSU-1B can also be used with other receiving systems by using a small external relay in the
receiver path. Power is removed and the receiver path can be shorted to ground when transmitting.
Detuning a Transmitting Antenna
Transmitting antennas always reradiate signals. When a receiving antenna is near a resonant
transmitting antenna, a transmitting antenna can receive and re-radiate noise and signals quite
efficiently. This almost always decreases receiving system performance.
Detuning a transmitting antenna requires changing the resonant frequency of the antenna when
receiving, and restoring it when transmitting. This requires a relay. Typical inexpensive relays for
transmitting are too slow to fully transfer before RF appears. A slow relay can damage the
transmitter system or cause severe signal quality issues. The
TVSU-1B will allow virtually any