Drake 300VMF+ Fixed Modulator User Manual

300VMF+

Commercial Video Modulator

(For use in NTSC systems)

INSTRUCTION MANUAL

is a registered trademark of the R.L. Drake Company

© Copyright 2013 R. L. Drake Holdings, LLC Printed in Taiwan.

Rev: 20130322
10037xx

2 Caution Statements

IMPORTANT SAFEGUARDS

This symbol is intended to alert the user to the presence of non-insulated
“dangerous voltage” within the product’s enclosure, that may be of suffi cient

magnitude to constitute a risk of electric shock to persons.

ing and maintenance (servicing) instructions in the literature accompanying

WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,

CAUTION: Do not attempt to service this product yourself as opening or removing covers may

ATTENTION: POUR PREVENIR LES CHOCS ELECTRIQUES, NE PAS UTILISER CETTE

VERT.

This symbol is intended to alert the user to the presence of important operat­the appliance.

CAUTION

TO REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK, DO NOT EXPOSE THIS
APPLIANCE TO RAIN OR MOISTURE

CAUTION

TO REDUCE THE RISK OF ELECTRIC SHOCK,
DO NOT REMOVE COVER (OR BACK)
NO USER SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED PERSONNEL.

DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE.

expose you to dangerous voltage or other hazards. Refer all servicing to qualifi ed

service personnel.

FICHE POLARISEE AVEC UN PROLONGATEUR, UNE PRISE DE COURANT
OU UNE AUTRE SORTIE DE COURANT, SAUF SI LES LAMES PEUVENT
ETRE INSEREES A FOND SANS EN LAISSER AUCUNE PARTIE A DECOU-

IMPORTANT SAFETY INSTRUCTIONS

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any ventilation openings. Install in accordance with the manufacturer's instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (includ-

ing amplifi ers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two
blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The

wide blade or the third prong are provided for your safety. If the provided plug does not fi t into your outlet, con-

sult an electrician for replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles,
and the point where they exit from the apparatus.

11. Only use attachments/accessories specifi ed by the manufacturer.

12. Use only with the cart, stand, tripod, bracket, or table specifi ed by the manufacturer, or sold with the

apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from
tip-over.

13. Unplug the apparatus during lightning storms or when unused for long periods of time.

14. Refer all servicing to qualifi ed service personnel. Servicing is required when the apparatus has been

damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have
fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or
has been dropped.

Table of Contents/Description/Specifi cations 3

TABLE OF CONTENTS
2 Caution Statements 5 Rear Panel Connections and Internal Jumper
2 Important Safety Instructions 6 Installation
3 Table of Contents / General Description 7 Frequency Allocation Charts
3 Specifi cations 8 Service / If You Need To Call For Help
4 Front Panel Controls, Indicators, and 9 Warranty
Connections

DESCRIPTION

The DRACOM 300VMF+ Video Modulator is a vestigial sideband heterodyne audio/video modulator that provides a
modulated visual and aural RF carrier output on any single EIA standard channel from channel 2 through channel 78 plus
channels 95 to 99. This range covers 54 through 552 MHz. Consult factory for custom channels. All aeronautical chan­nels are offset positive with a tolerance of ±5 kHz as required by FCC rules. The 300VMF+ is designed to accept video
and audio baseband signals from a satellite receiver, TV camera, video tape recorder, TV demodulator or similar equip­ment. The heterodyne conversion system, in conjunction with the use of a SAW fi lter, insures optimum vestigial selectivity
for adjacent channel headends. The modulator accepts standard (sync negative) polarity video at a 0.7 -1.5 Vpp level. All
level controls are located on the front panel for ease of operation.

SPECIFICATIONS

RF

Frequency Range:

Channels Available:

FCC Frequency

Offsets:

Output Level:

Output Impedence:

Output Test:

A/V Ratio:

Frequency Stability,

Visual:

Aural Intercarrier

Frequency:

Spurious Outputs:

In-Channel C/N:

Broadband Noise:

54 - 552 MHz.

Factory-ordered for a single channel:

EIA CATV channels 2 to 78 and 95 to 99.

All aeronautical channels offset positive
with a tolerance of ±5 kHz.
+55 dBmV, (typically adjustable from +43
to +55 dBmV).
75 OHMS, return loss of 14 dB, nominal.

-30 dB, ±3 dB (referenced to
RF OUTPUT level).
Audio Carrier -20 to -12 dB referenced to
video carrier, adjustable.

Within ±10 kHz of assigned channel
frequency; ±5 kHz on FCC
offset channels.

4.5 MHz, ±5 kHz.

-60 dBc minimum, measured at -15 dB A/V
ratio and with modulator output level of
+55 dBmV.
Better than 60 dB.

-95 dBc @ ±30 MHz or
greater spacings. (Specifi ed levels are
referenced to the video carrier and
measured in a 4 MHz bandwidth).

VIDEO

Input level for 87.5%

Modulation:

Input Impedance:

Frequency Response:

Video S/N:

L/C Delay:

Differential Gain:

Differential Phase:

AUDIO

Input Level for

25 kHz Peak Deviation:

Input Impedance:

Pre-emphasis:

Frequency Response:

4.5 MHz Intercarrier Stability:
Total Harmonic Distortion:

Hum and Noise:

GENERAL

Modulator Power

Requirement:

Auxiliary AC Outlet:

Total AC Power Input:

Operating Temperature

Range:

Size:

Weight:

Connectors:

1 Vp-p ±3 dB, manual gain adjust with
front panel control.
75 Ohms, return loss of 18 dB
minimum.
Flat ±2 dB from 30 Hz to 4.2 MHz.
60 dB, luminance weighted.
Within 50 nSec of 0 nSec L/C delay
(complies with FCC rules, 76.605).
Less than ±5% (10 to 90% APL).
Less than ±5 degrees (10 to 90% APL).

175 mV rms minimum. Manual gain
adjustment with front panel control.
10K Ohms, unbalanced.
75 mSec.(fl at by moving internal jumper)
40 Hz to 15 kHz, ±1.5 dB, referenced to
75 mSec pre-emphasis curve.
Within ±5 kHz, 00 C to +500 C.

1.5% maximum.

-60 dB minimum, referenced
to 25 kHz peak deviation.

115 VAC ±10%, 60Hz, 10 Watts.
Nominal 120 VAC, 600 Watts, maximum.
Nominal 120 VAC 60 Hz,
610 Watts, maximum.

0 C to +50 C, ambient.
19” W x 1.75” H x 4.0” D.

3.6 lbs.
Video input, Audio input, RF output, and
Monitor output are all type F.

4 Front Panel Description

F1 F2 F3 F4 F5 F6 F7

F1 - POWER Indicator

Lights when the unit is connected to a source of AC
power.

F2 - OUTPUT TEST Connector

Provides a reduced level sample of the RF output signal.
The level at this connector is approximately 30 dB lower in
level than the RF OUTPUT signal. It is used to monitor
the active signal without affecting the level or quality of the
RF output signal.

F3 - CHANNEL Designation

The label indicates the fi xed channel output for your
particular model. The 300VMF+ is capable of fi xed

channel output (factory tuned) within the following
ranges: Channel 2 through 78 and 95 through 99.

F4 - RF OUTPUT LEVEL

This screwdriver adjustment permits decreasing the RF

output level a minimum of 12 dB below its specifi ed

output level as the control is rotated counterclockwise.
The maximum output level of +55 dBmV is set with the
adjustment approximately fully clockwise.

NOTE: If an output level of less than +43 dBmV is
required, add an attenuator of the appropriate value at
the modulator output.

Example: For an output level of +35 dBmV, add a 12 dB
attenuator pad to the modulator output and set the
output level to +47 dBmV.

F5 - A/V RATIO Control

This screwdriver adjustment varies the level of the aural
carrier over a range from 12 to 20 dB below the visual
carrier. The aural carrier should normally be adjusted to
approximately 15 dB below the visual carrier (normal
operation). Clockwise rotation increases the aural carrier
level and thus decreases the A/V ratio.

F6 - AUDIO LEVEL Control

The setting of this screwdriver adjustment determines the
peak aural carrier deviation. Clockwise rotation
increases the carrier deviation. After installing the unit,
and with an audio source connected, adjust the AUDIO
LEVEL control for 25 kHz deviation. If an audio
modulation meter is not available, use a TV set and
adjust for equal volume as compared to a known off-air
broadcast. Monitor for a few minutes to assure that
maximum volume of the audio source program does not
cause an over-modulation condition.

F7 - VIDEO LEVEL Control

The setting of this screwdriver adjustment determines the
video modulation level. Clockwise rotation increases the
modulation depth. After installing the unit, and with a
nominal 1 Volt P-P video source connected, adjust the
VIDEO LEVEL control for the correct percentage of
modulation (87.5%). If test equipment is not available for
such measurements, then adjust for proper picture
contrast when viewed on a TV set (compare with known
off-air broadcast picture quality).

Rear Panel Description and Internal Jumper 5

R1 R2 R3 R4 R5

R1 - VIDEO INPUT Connector

This is the baseband video input to the IF circuits. This
input accepts baseband through 4.2 MHz video at levels
from 0.7 Vp-p to 1.5 Vp-p
.

R2 - AUDIO INPUT Connector

This is an unbalanced audio input to the IF circuits. This
input accepts 40 Hz through 15 kHz audio at a nominal
level of 250 mV RMS (approximately -10 dBu).
If a separate BTSC stereo encoder, such as the Drake
MMTS20, is to be used with this modulator, this jack can

input 40 Hz through over 50 kHz with fl at response if
internal jumper J8 is set to fl at - see below)

R3 - RF OUTPUT

This is the modulator output.

INTERNAL JUMPER SETTING - AUDIO RESPONSE

Internal jumper J8 may be used to disable the 75 uSec
pre-emphasis (normal setting). Flat response may be
chosen if an external BTSC stereo signal is to be input to
the modulator through the audio input jack. To access this
jumper, disconnect the unit from AC power. Remove the
three screws holding the top cover of the chassis in place.
Remove top cover. J8 is a three pin header with J8
printed on the PCB. After setting this jumper, reinstall the
cover before returning power to the unit.

R4 - AC OUTLET Receptacle

This is a power receptacle for other equipment and is
rated at 600 W maximum; 120 V, 5 Amp. This receptacle
is unfused and unswitched.

R5 - LINE CORD

This is a three-wire power cable. When the cable is
connected to a properly wired AC power line outlet, this
cable grounds the instrument cabinet. Connect to a
115 VAC ±10%, 60 Hz source. Do not defeat the safety
purpose of the attached line cord plug.

NORMAL RESPONSE of 75 uSec = Jumper in the 1-2
position (shorting pins 1 and 2 of the J8 header). Use this
setting for normal mono audio input. This is the factory
default setting.

FLAT RESPONSE = Jumper in the 2-3 position (shorting
pins 2 and 3 of header J8). Change to this setting when
an external BTSC stereo encoder is used with the
300VMF+.

6 Installation

CONNECTIONS AND CONTROLS

All connections to and from the 300VMF+ are made through
the rear panel. Figure 4 shows a typical two channel
installation using a typical satellite receiver as a signal
source. Additional channels can be added by using
additional 300VMF+ modulators and either multi-port
combiners or combinations of two-port combiners.

INSTALLATION NOTES

Level adjustment provides optimum performance in
multichannel installations. The modulator outputs should be
checked periodically with a spectrum analyzer to maintain a
±1 dB variation of adjacent channel carriers. Aural/Visual
(A/V) ratios should be held to -15 dB or less.

The ‘RF Output Level’ and ‘A/V Ratio’ controls are used
respectively to make these adjustments. If an output level
of less than +43 dBmV is required, add an attenuator of the
appropriate value to the modulator output.

Example: For an output level of +35 dBmV, add a 12 dB

attenuator pad to the modulator output and set the output
level.

RACK MOUNTING

Adequate ventilation is very important in multichannel
installations. Units should be spaced apart by at least one
panel height wherever possible, and some air movement is
advisable in enclosed rack cabinets. Excessive heat will
shorten component life and modulator performance will be
degraded without proper cooling.

Frequency Allocation Charts 7

Table 1 CHANNEL ASSIGNMENTS

8 Service / If You Need To Call For Help

SERVICE INFORMATION

You may contact the R.L. DRAKE HOLDINGS, LLC
Service Department for additional information or assist­ance by calling:

[phone]

Monday through Friday
8:00 A.M. to 4:00 P.M. EST, except on holidays.

You may also contact the R.L. DRAKE HOLDINGS, LLC
Service Department by E-mail at the following address:

[e-mail]

or by Telefax:

[phone].

IF YOU NEED TO CALL FOR HELP

Call our Customer Service/Technical Support line a
[phone] between 8:00 A.M. and 4:00 P.M.
Eastern Time, weekdays. Please have the unit’s serial

number available. We will also need to know the specifi cs

of any other equipment connected to the unit.
When calling, please have the unit up and running, near
the phone if possible. Our technician(s) will likely ask
certain questions to aid in diagnosis of the problem. Also,
have a voltmeter handy, if possible.

R.L. DRAKE also provides technical assistance by e-mail:

[e-mail]

Should you want to return your unit for service, package
the unit carefully using the original carton or other
suitable container.

Write your return address clearly on the shipping carton
and on an enclosed cover letter describing the service
required, symptoms or problems. Also include your
daytime telephone number and a copy of your proof of
purchase.

The unit will be serviced under the terms of the
R.L. DRAKE HOLDINGS, LLC Limited Warranty and
returned to you.

Red is an overnight service.

Send the unit in a way that it can be traced if we can’t
verify receipt of shipment. We suggest UPS or insured
postal shipment.

If the unit is still under the original owner’s warranty,
R.L. DRAKE will pay the cost of the return shipment to
you. Our return shipping policy is that we will return it
UPS Brown if received Brown or by US Mail, it will be
returned Blue if received Blue or Red—or it will be
returned however you prefer if you furnish the return cost
for the method you select.

or by Telefax:

[phone].

Many of the products that are sent to us for repair are in
perfect working order when we receive them. For these
units, there is a standard checkout fee that you will be
charged. Please perform whatever steps are applicable
from the installation sections of the Owner’s Manual
before calling or writing—this could save unnecessary
phone charges. Please do not return the unit without

contacting R.L. DRAKE fi rst: it is preferred to help
troubleshoot the problem over the phone (or by mail) fi rst,

saving you both time and money.

Inside the carton, enclose a note with your name,
address, daytime phone number, and a description of the
unit’s problem.

The unit must be sent to the following address:

Service Department R.L.
DRAKE HOLDINGS. LLC

710 Pleasant Valley Drive
Springboro, OH 45066 U.S.A.

Be sure to include your street address which will be
needed for UPS return.

UPS Surface (Brown Label) takes 7-10 days to reach us de­pending on your location.
Blue takes 2-3 days.

If the unit is out of warranty, use one of the following
methods for return shipment:

1) You designate billing to American ExPress, VISA,
MasterCard or Discover card;

2) You prepay the service charges with a personal check,

or

3) You specify some other method of return and payment.

When calling, the technician can estimate the repair
charges for you over the phone. This is another good
reason to call before sending a unit in for repair.

Typically, equipment is repaired in fi ve to ten working

days after it arrives at DRAKE if we have all the facts. If
we must call you, it may take longer. R.L. DRAKE HOLD­INGS, LLC is not responsible for damage caused by
lightning, non-professional
alterations, “acts of God”, shipping damage, poor
storage/handling, etc. DRAKE will make note of any
shipping damage upon receipt.
You will need to send proof of purchase to receive
warranty service. Typically, a copy of the invoice from a

DRAKE dealer will suffi ce. The warranty is for the

original owner only and is not transferable.

WARRANTY 9

One Year Limited Warranty

R.L. DRAKE HOLDINGS LLC warrants to the original purchaser this product shall be free from defects in material
or workmanship for one (1) year from the date of original purchase.

During the warranty period R.L. DRAKE HOLDINGS LLC or an authorized Drake service facility will provide,
free of charge, both parts and labor necessary to correct defects in material and workmanship. At its option, R.L.
DRAKE HOLDINGS LLC may replace a defective unit.

To obtain such a warranty service, the original purchaser must:

1. Retain invoice or original proof of purchase to establish the start of the warranty period.

2. Notify R.L. DRAKE HOLDINGS LLC or the nearest authorized service facility, as soon as possible after
discovery of a possible defect, of:

a) the model and serial number,

b) the identity of the seller and the approximate date of purchase; and

c) A detailed description of the problem, including details on the electrical connection to associated

equipment and the list of such equipment.

3. Deliver the product to R.L. DRAKE HOLDINGS LLC or the nearest authorized service facility, or ship
the same in its original container or equivalent, fully insured and shipping charges prepaid.

Correct maintenance, repair, and use are important to obtain proper performance from this product. Therefore
carefully read the Instruction Manual. This warranty does not apply to any defect that R.L. DRAKE HOLDINGS
LLC determines is due to:

1. Improper maintenance or repair, including the installation of parts or accessories that do not conform

to the quality and specifi cations of the original parts.

2. Misuse, abuse, neglect or improper installation.

3. Accidental or intentional damage.

All implied warranties, if any, including warranties of merchantability and fi tness for a particular purpose, terminate

one (1) years from the date of the original purchase.

The foregoing constitutes R.L. DRAKE HOLDINGS LLC’S entire obligation with respect to this product, and the
original purchaser shall have no other remedy and no claim for incidental or consequential damages, losses or
expenses. Some states do not allow limitations on how long an implied warranty lasts or do not allow the exclusions
or limitation of incidental or consequential damages, so the above limitation and exclusion may not apply to you.

This warranty gives you specifi c legal rights and you may also have other rights which vary from state to state.

This warranty shall be construed under the laws of Ohio.

For Service, contact:

R.L. DRAKE HOLDINGS LLC

710 Pleasant Valley Drive

Springboro, Ohio 45066. USA

Customer Service and Parts Telephone: [phone]

Telefax: [phone]

Web Site: http://www.rldrake.com

[THIS PAGE IS INTENTIONALLY LEFT BLANK]

[THIS PAGE IS INTENTIONALLY LEFT BLANK]

R.L. Drake Holdings, LLC

710 Pleasant Valley Drive

Springboro, OH 45066

[phone]

www.rldrake.com