DX Engineering DXE-FVC-1 Instruction Manual

Feedline Voltage Coupler

DXE-FVC-1

DXE-FVC-1-INS Rev. 5b

© DX Engineering 2017

1200 Southeast Ave. - Tallmadge, OH USA

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Introduction

The DXE-FVC-1 Feedpoint Voltage Coupler is a versatile receive feedline or control cable voltage
injector and switching interface. It is used to control receive antenna switching devices through the
feedline or on a two conductor control cable.

The DXE-FVC-1 converts 12 Vac voltage input to fuse-protected 0V, +12 Vdc, −12 Vdc and 12
Vac output voltages. The voltage output of the DXE-FVC-1 is simultaneously sent on the receive
feedline through the ANT port F connector and on the OUT pin of the removable 5-terminal rear­panel connector for use with a two-conductor control cable. This voltage sequence can be used to
provide 4-direction switching of an antenna array or selection of four different antennas.

Connection of the DXE-FVC-1 to the radio equipment receive antenna input may be made using
either the standard RCA phono -or- the type F connector. This allows use of readily available RF
compatible RCA phono patch cords or 75 Ω coaxial cable and connectors, and protects the receive
system from accidental connection to transmitting equipment.

As supplied, the DXE-FVC-1 input is ready to be voltage switched using the DX Engineering
DXE-CC-8A Control Console, 8 Position Switch. Alternatively, the user may choose to use a rotary
switch by changing an internal jumper in the DXE-FVC-1 to use input grounding switching control.

Features

 External 12 Vac heavy duty power transformer included
 Metal housing – superior shielding, rugged, easy mounting
 Convenient installation – mounts anywhere in your shack
 Rugged control connector – removable, reliable solder-less connections
 Receive only connectors, Type F and RCA phono - used to protect receive equipment
 Internal thermal reset fuse − full protection against accidental shorts
 Flexible input − BCD voltage or 1-of-4 ground switching
 Dual LEDs − show control voltage output, used for directional indicators

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Connections & LEDs

#

Label Designation

Description

1

12 VAC IN

Standard 2.1 mm connector for 12 Vac input
Included with the DXE-FVC-1 is a 12 Vac wall transformer

2

OUT-AC-NEG-POS-GND

Removable control cable input connector

3

ANT

F Connector for 75-ohm coaxial cable from the

DXE-FVC-1 connection to receive antenna system

4

RADIO

F connector for connection of 75-ohm coaxial cable from the

DXE-FVC-1 to the customer's Radio Receive Input

5

RCA phono plug for connection from DXE-FVC-1 to the
customer's Radio Receive Input

6 & 7

- AC +

●●

Red LED - when lit it indicates that +12 Vdc is being sent
out through the ANT connection

Green LED - when lit it indicates that -12 Vdc is being sent
out through the ANT connection

Red and Green LED - when both are lit, they indicate 12
Vac is being sent out through the ANT connection

When both the Red and Green LED's are not lit, 0 v is
applied to the ANT connector

●●

●●

●●

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NOTE: The DXE-FVC-1 uses 1/2-wave rectification for the DC control voltages. When

measuring the output using an RMS or average reading DVM, the normal DC output of

the DXE-FVC-1 will indicate a nominal +/– 6 Volts. The AC voltage will measure 12 Vac.

Figure 1 - DXE-FVC-1 removable connector

The green connector on the rear of the DXE-FVC-1 is a two part polarized connector. This
connector, for the control wires, is removed by pulling it straight off. This will allow easy wire
placement or servicing as needed. When pushing the connector back in place, ensure you press
straight inward. Refer to Figure 1.

Connections are made with a screwdriver; no soldering is required. Do not attempt to solder wires
to the connector, and do not over-tighten the screws. Remove 1/4 inch of insulation from each
control wire so the screw terminals tighten on the wire and not the insulation. This will also protect
adjacent wires from the potential of shorting together. Stranded wire should be tightly twisted or
very lightly tinned before insertion. Open terminal slots by turning the screws CCW (counter clock­wise) before wire ends are inserted. Do not force the screw beyond the stop.

Connecting the DXE-FVC-1 to a receive antenna system uses a standard type F connector. This
allows use of readily available 75-ohm coaxial cable and connectors, and protects the receive
system from accidental connection to transmitting equipment.

Installation

The DXE-FVC-1 is typically mounted near the operating position so the LEDs are visible, but any
protected location with ambient temperatures below 150° F non-condensing (65° C) is acceptable.

The DXE-FVC-1 unit requires 12 Volts AC power. The unit will not
function properly if 12 Vdc is used on the input. The included wall

transformer will provide 12 Volts AC power for the DXE-FVC-1.

A malfunction will occur if 12 Vdc is used to power the DXE-FVC-1.

Figure 2 - Transformer Label

The switched output voltages appear simultaneously on both the ANT feedline connector and the
rear panel OUT terminal on the 5 position green connector. The OUT terminal is used for
supplemental switching control output only and cannot be used to provide power to any unit.

4

Internal Jumper Settings

Note: The DXE-FVC-1 must be powered by 12 Vac in order to operate no matter which
way JMP1 is set.

Internal jumper JMP1 is used to select the input control function that controls the DXE-FVC-1.

Remove the four screws holding the cover to the base to gain access to the internal jumper.

Figure 3 - 4 screws that hold the DXE-FVC-1 case together

The factory default setting has the jumper JMP1 connecting
to the two pins below EXT.

Figure 4 - Factory default setting for JMP1

When JMP1 is set to EXT, external +12 Vdc (nominal) is required for BCD input switching control.
The default jumper position, EXT, sets the DXE-FVC-1 to respond to external source voltages of
+9 to +15 Vdc in order to control the output voltages. The DXE-CC-8A Control Console provides
these voltages.

If you wish to use a simple switch closure to ground on the input in order to control the output, then
change the jumper setting to INT. Control current is low (less than 100 mA). With JMP1 set to INT,
the DXE-FVC-1 internally sources the control voltage. This allows using a 1-of-4 input switching
control scheme by grounding the appropriate input pin, which selects the desired output. Switching
can be accomplished with a simple, inexpensive SP4T rotary switch or a push-button switch
arrangement.

BCD control interface systems require a 3-conductor control cable. 1-of-4 logic requires a 4­conductor control cable. Use of the supplemental control OUT output would require a 2-conductor
cable. These conductor counts include the ground return.

5

Connections

DXE-F6-SPL or DXE-F6-1000 high quality 75-ohm “flooded” RG-6 type coaxial cable is

recommended. Flooded style cables have the distinct advantage of automatically sealing small
accidental cuts or lacerations on the jacket. Flooding also prevents shield contamination and the
coaxial cable can be direct-buried. Moisture coming into the shield often occurs at
the connector and can cause increased system noise. For superior watertight
connections, use DXE-SNS6-25 Snap-N-Seal connectors. Weather-tight Snap-N­Seal connectors CANNOT be installed with normal crimping tools or pliers. The use
of the DXE-SNS-CT1 installation tool is available from DX Engineering.

The F type ANT connector on the DXE-FVC-1 is used to connect the receiving antenna feedline.
The appropriate switching voltage is applied through the feedline by the DXE-FVC-1. It is critical
that the feedline connectors remain dry and you do not place any intentional DC shorts or opens on
the feedline between the DXE-FVC-1 and anything being controlled. This includes lightning
arrestors, splitters or any other accessory not intended for feedlines carrying power or control
voltages. The radio connections go to the receiver using either the type F or RCA phono connector.

The DXE-FVC-1 requires 12 Vac to operate. Connect the included wall transformer to the 2.1 mm
barrel plug on the DXE-FVC-1 labeled "12 VAC IN" .

Control connections for the DXE-FVC-1 labeled AC, NEG, POS and GND as well as the
supplemental output labeled OUT are made at the removable, green 5-terminal
screw-type connector. Do not attempt to solder wires to this connector. Remove
1/4 inch of insulation from each 16 to 24 gauge control wire, insert the wires in the
appropriate screw terminal. When tightening ensure the connection is secure
against the wire and not the insulation. Be certain that adjacent wires are
positioned to eliminate the possibility of shorting. Stranded wire should be tightly
twisted or very lightly tinned before insertion. Open terminal slots on the
removable green connector by turning the screws counter clock-wise before the
wire ends are inserted. Do not force the screw beyond the stop. Tighten each
screw securely clock-wise without over-tightening.

The example above

Note: The ground connection (GND) uses color coded
should be connected to your station ground buss. wire. Your wire

may not look the same

Input/Output Logic and Connection Examples

The DXE-CC-8A Control Console may be used to provide the voltage or a user supplied switch
may be used to provide the voltage or grounding, required by the DXE-FVC-1 input in order to
control the output. The following tables show the input and output combinations for both schemes.
Each input state results in a different output voltage thru the ANT type F-connector and on the OUT
supplemental terminal per Table 1. Note the LED indications.

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