SW VDA38B, VDA38H User Manual

RF Distribution

Amplifiers

VDA38B
VDA38H

ir out

gnd

+15vdc

B

(pwr)

Mod input

A

ir out

gnd

+15vdc

B

(pwr)

Mod input

3 X 8 Bi-Directional Video Distribution Amplifier

TV output

3 X 8 High Headroom Video Distribution Amplifier

TV output

VDA38B

CATV

VDA38H

CATV

A

Models VDA38B & VDA38H Video Distribution Amplifiers

Things To Watch For:

The VDA38B or VDA38H is the heart of any RF distribution system. Each is a 3–IN
by 8–OUT RF distribution amplifier that connects as many as 8 televisions to cable
or antenna while maintaining optimum signal strength to all TVs. Each also has the
capability of sending IR down each coax run for control of local TVs or video source
components.

Contents:

VDA38
Power Supply (15VDC @ 300mA)
Power/IR adaptor

ir out

gnd

+15vdc

VDA38B

CATV

B

(pwr)

Mod input

A

3 X 8 Bi-Directional Video Distribution Amplifier

TV output

Herringbone interference on modulator channel (diagonal lines): You may have

chosen a channel number that is not completely vacant. Distant UHF stations may
not be watchable, but will cause interference if you try to create a new channel at
the same frequency. Also, cable companies often have extra signals where there
should be none. Try moving the modulator channel to another number. You may
have to add a low pass filter to remove the cable company noise. If the filter does
not work, try adding a DC-block to remove common mode interference.

Herringbone interference on many channels, including modulator channels
(disappears when you remove the CATV/antenna feed): The RF amplifier can be

overloaded by abnormally strong signals. Often, you can cure the problem with a
simple attenuator. Use a variable attenuator and try to find a signal level where the
interference just disappears. Sometimes, the problem is one station is far stronger
than the rest. In this case, attenuating all of the signals with a simple attenuator
will cause the desired stations to be weak (snowy). You must reduce the strength
of the only offending station. A common FM trap will help if the problem is a nearby
FM tower. If the problem is a nearby TV station, often the station management can
provide suitable filters.

We recommend using only RG-6 coax when wiring a house for RF distribution.
Why? Although good RG-59 has only slightly more loss than RG-6, it is harder to
find a good RG-59 with wide bandwidth. RG-6 is a little more expensive and a little
harder to run (it is thicker). But you will avoid surprises if you stick to RG-6.

Model Differences:

The VDA38H is for antenna or uni-directional cable systems and has the highest
headroom of any coax panel available in the market.

PRINTER'S INSTRUCTIONS:

The VDA38B is for bi-directional cable systems providing a 5-42MHz back channel
for cable modems or interactive set-top boxes.

Accessories:

Specifications:

Gain:
CATV/Antenna port to output

TARGET

LED

EMITTER

TO
TV

POWER

CXIRWP

COAX/IR wall plate
breaks out the IR signal
from the coax cable.
Emitter jack for source
control. Power supply
included.
Powers the VDA38
remotely and has a built­in IR wall plate.
(fits standard Decora)

MOD4000 4-Channel Digital Modulator

4-Channel Digital Modulator

A B C D

select program

IR

pll frequency control

MOD4000

Modulator input to output
Output to CATV (reverse)

Isolation:
Modulator input to CATV/Ant

Max CATV/Antenna input:

Power Supply: (included)

General:
Width x height x depth (in)
Shipping weight

INSTR,INSTL,VDA38B_H,OEM - LINEAR P/N: 222759 X2 - INK: BLACK - MATERIAL: 113 GSM WHITE PAPER COATED 2-SIDES (C2S) - SIZE: 8.500" X 11.000" - FOLDING: ALBUM FOLD, BINDING: SADDLE-STITCH - SCALE: 1-1 - IMAGE 2 OF 4

2

Typical Installation:

The VDA38 works like a zero-loss splitter. The signals you put on the
antenna/CATV input will appear on the outputs with about 3dB of gain.

ir out

gnd

Modulator may be

connected to A or B input.

+15vdc

B

(pwr)

A

Mod input

3 X 8 Bi-Directional Video Distribution Amplifier

TV output

VDA38B

CATV

CATV or

Antenna

POWER

OUTPUT

LOOP

AUDIOAUDIO

VIDEO

recommended

for all runs

Up to 8 TVs

DVD, VCR

or Satellite

Circuit Breaker:

The VDA38 has a built-in circuit breaker. If the power LED is not lit, reset the circuit
breaker by disconnecting and reconnecting the power supply. If the system does
not reset, look for an installation error.

VDA38

RG-6 coax

B

(pwr)

Mod input

A

TV out

Note: Connecting a 75ohm

terminator directly to an
output of a VDA38 will
cause the circuit breaker to
trip.

Power LED

3