Operating Manual and User Guide

BROADCAST FM EXCITERS

FM25E

FM50E

FM250E

FM SERIES

PTEK

Limited WarrantyPTEK (SELLER) warrants that products are free from defects in material and workmanship and meet

performance specifications provided, however, that:

(A) SELLER’ liability under this Warranty is limited to repairing or replacing, at its option, any

product delivered here under not conforming to this Warranty;

(B) This Warranty is limited to a period of two years;

(C) Minor deviations from specifications which do not affect performance are excluded from this

Warranty; and

(D) SELLER shall be liable under this Warranty only if:

(1) It is promptly notified in writing by the Buyer upon discovery of the failure of any product to

conform to this Warranty,

(2) The product is returned to SELLER, transportation charges prepaid by the Buyer,

(3) The product is received by SELLER not later than ten days after the last day of the two-year

period of this Warranty, and

(4) SELLER’ examination of the Product discloses to SELLER’S reasonable satisfaction that

such defects or failures as may exist have not been caused by misuse, neglect, improper

installation, repair, alteration, accident or shipping.

The Buyer will prepay freight to and from SELLER on products serviced here under at SELLER’ plant; but

SELLER may, at its option, elect to perform any repairs here under at the Buyer’s place of business.

The foregoing constitutes SELLER’S entire Warranty expressed, implied and/or statutory, except as to

title, and states the full extent of SELLER’S liability to the Buyer or to any other party for any breach of

such Warranty and for damages, whether direct, special, incidental or consequential; and, other than as

expressly provided in this document. No Warranties, expressed or implied, including any Warranty or

merchant ability or of fitness for a particular purpose, are made. No employee, representative or agent of

SELLER has any authority, expressed or implied, to alter or to supplement the terms of this Warranty.

Warranty Service

The Limited Warranty covers parts and labor to the original purchaser for two year. Damage

caused by misuse or shipping is excluded from the warranty. Before returning units or material,

contact the factory for a Returned Material Authorization (RMA) number. Ship all material

prepaid. Defective material should be addressed to:

PTEK

PTEK111 N. Vista Rd. Ste 3E

Spokane Valley, WA 99212(509) 290-6652

customerservice@ptekpower.com

Safety

BEFORE APPLYING POWER

GROUND THE EXCITOR.

Fuses

.

DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE

DO NOT REMOVE THE EXCITOR COVER

Output connector

Verify that the line voltage is 115V

To minimize shock hazard, the excitor chassis must be connected to an electrical ground. the excitor must beconnected to the ac power mains through a three-conductor power cable, with the third wire firmly connected to anelectrical ground (safety ground) at the power outlet. Any interruption of the protective (grounding) conductor ordisconnection of the protective earth terminal will cause a potential shock hazard that could result in personal injury.If the excitor is to be energized by any other source be certain the that chassis is connected to a separate safetyground.

Only fuses with the same required current, voltage rating, and specified type (normal blow, time delay, etc.) should beused. Do not use repaired fuses or short-circuited fuseholders. To do so could cause a shock or fire hazard

Do not operate the power amplifier in the presence of flammable gases or fumes.

Operating personnel must not remove the exciter cover. Component replacement and internal adjustments must bemade only by qualified service personnel.

The type N output connector carries dangerously high RF voltages which present a shock and burn hazard.operate this excitor with out the out put connector properly terminated in either an adequately rated load or antenna.

NEVER

Page 4

MONAURAL

OPERAT ION

Audio Input Impedance:

Audio Input Level:

Audio Frequency Response:

Total Harmonic Distortion:

FM S/N Ratio (FM Noise):

Asynchronous AM S/N Ratio (AM Noise):

Synchronous AM SIN Ratio (Incidental AM Noise):

600 ohms, balanced

+10 dBm (6.93 volts peak-to-peak) at 600 ohms for75 kHz deviation

+/-0.5 dB; flat or 75 microsecond pre-emphasis, 20Hz to 15kHz (other time const. available)

0.15% max.; 20 Hz to 15 kHz

70 dB min. below 75 kHz deviation at 400 Hz,measured within a 20 Hz to 15 kHz bandwidth with75 microsecond de-emphasis

60 dB RMS. below carrier; reference: 100% AMmodulation, at 400 Hz with 75 microsecond de-emphasis, no FM modulation

57 dB below carrier; reference: 100% AMmodulation, full power at 400 Hz with 75uS de-emphasis, FM +/- 75 kHz, 400Hz

Specifications

ENV I RO NM ENT

Altitude: Ambient Temperature0-10,000 ft -10 to +50 oC

WIDEBAN D

OPERAT ION

Inputs:

Input Level:

Wideband Amplitude Response:Composite Unbalanced 10k OhmsSCA 1 Unbalanced 10k Ohms

1.25 V RMS. (3.54 volts peak-to-peak) for 75 kHzdeviation

+/-0.5 dB, 20 Hz to 100 kHz

G ENERA L

Rated Power Output:

Power Consumption:

Frequency Range:

Frequency Control:

Frequency Stability:

Output Impedance:

Output Connector:

VSWR:

Modulation Type:

Modulation Capability:

Multi-Meter Indication:

Harmonic Attenuation:

25W, 50W, 150W, 300W

150 W (for 50W model)

87.7 to 108 MHz, in 200 kHz steps (other step size toorder)

Phase locked loop frequency synthesis from highstability master oscillator

+/- 1.2 kHz

50 ohms

Type -"N" female

1.5:1 for full power, derate to 0 at inf.

Direct carrier frequency modulation

To 100 kHz deviation

Deviation, Forward Power, Reverse Power, Final I & V

-70 dB, min.

1

45

Rear panel layout

8 7 6

5

1 2

3 4

Page 6

Front panel layout

. DEVIATION

2 3

8

AC IN

SCA

FUSE

RF OUTPUT

FINAL CURRENT

FINAL VOLTAGEFORWARD POWER

REVERSE POWER

ADJPOWER

OFF

OPERATE

REMOTE OFF

FAULT

DRIVE LOW

FM Series

PTEKFM25E

DEVIATION

3025201510

5

OUTPUT POWER W (REV X0.1)

4.040

3.030

2.020

1.0100

0 AMPS

PTEK

VOLTS

DEVIATION kHz

100

755025

ON

REMOTE

PWR PWR

VOLTAGE

FWD REV

OFF

CURRENTFINAL

MONO IN600 OHMS

RAISE

LOWER

GAIN

GAIN

GAIN

COMPOSITE

10MHz 1MHz 100kHz

FREQUENCY

Key Element Description

1 AC IN & FUSE 110 VAC input and Fuse 10A

2 COMPOSITE Unbalanced wide band composite input

3 SCA Unbalanced wide band input

4 RF OUT TYPE N RF Output

5 FREQUENCY SELECTION Set switches for frequency selection (only takes effect when unit is switched

from off to on)

6 Accessory connector Connections for; Remote off and DC indications of Forward Power, Reverse

Power, Final Voltage, Final Current and Deviation.

8 SERIAL NUMBER Serial number for reference purposes

Page 7

Key Element Description

1 METER Indicates Forward Power, Reverse Power, Final Voltage, Final Current and

Deviation

2 OPERATE Switch and

Indicator

This switch sets the FM Broadcast Amplifier to the Operate Mode; 110 VAC is

applied to the line transformers and this amber indicator is lit.

3 REMOTE OFF Indicator This red LED indicator is lit when the FM Broadcast Amplifier remote off

terminals (rear panel) are open circuit.

3 DRIVE LOW Indicator This red LED indicator is lit when the FM Broadcast Amplifier can not make

the power requested, because for example low drive power.

5 FAULT Indicator This red LED indicator is lit when the FM Broadcast Amplifier is in a fault

condition. This can be for one or combination of the following:-

Over drive, High supply Voltage, High load VSWR, Over temperature.

6 Meter Select Switch This switch selects one of the following to be presented on the meter (1):-

Forward Power, Reverse Power, Final Voltage, Final Current and Deviation.

7 ADJ POWER control This control adjust the output power from rated full power to less than 50%.

8 Ventilation Filter This provides for filtering the environmental air as it is drawn into the cabinet

by the internal fan (not used on FM10E).

Refer to the Table below for the following description. The installer should assure the ac line voltage is turned OFFbefore performing this procedure. The electrical connections are installed at the Exciter rear panel.

Installation-Electrical

Page 8

RG8 TO ANTENNA/PA

PART OF USER SUPPLIED REMOTE CONTROL

BALANCED MONO IN

OR (NOT BOTH)

FROM STEREO ENCODER OR STL

AC IN

SCA

FUSE

RF OUTPUT

ON

REMOTE

PWR PWR

VOLTAGE

FWD REV

OFF

CURRENTFINAL

MONO IN600 OHMS

RAISE

LOWER

GAIN

GAIN

GAIN

COMPOSITE

10MHz 1MHz 100kHz

FREQUENCY

Refer to the Table below for the following procedure.

Turn-On Checkout

Page 9

Stereo pilot level adjustment

With Stereo encoder (optional)connectedto composite input, adjust composite gaincontrol to give deviation meter readingshown (aprox 7.5kHz)

Page 10

Frequency Selection

10s MHz Switch

“0” is 10 (100MHz)

PLEASE NOTE, FREQUENCY CHANGESSHOULD BE MADE WITH THE UNIT TURNED

OFF

100kHz Switch1MHz Switch

Example Shown 104.5MHz

Reading the front panel meter

300250

100

020015050

50 75251000

DEVIATION kHzAMPS VOLTS(X10)

52.5100

7.5

PTEK

POWER Watts

300250

100

020015050

50 75251000

DEVIATION kHzAMPS VOLTS(X10)

52.5100

7.5

PTEK

POWER Watts

300250

100

020015050

50 75251000

DEVIATION kHzAMPS VOLTS(X10)

52.5100

7.5

PTEK

POWER Watts

300250

100

020015050

50 75251000

DEVIATION kHzAMPS VOLTS(X10)

52.5100

7.5

PTEK

POWER Watts

Forward Power

The forward power reading is amount of power going to theantenna. The example shown is a reading of 250 Watts. Thissetting can be changed with the front panel raise lowerswitch and should be set to the licenced power output (see“calculation transmitter power setting”).

Reverse Power

The Reverse power reading is amount of power returningfrom the antenna. The example shown is a reading of 2.5Watts. A correctly matched antenna should not return anypower back to the transmitter. The ration of Reverse Powerto Forward Power in this example 2.5/250 would give areturn loss of 1% or -20dB this would classified as a goodantenna. Reverse Powers approaching 10% will cause thetransmitter to reduce the output power (See antenna VSWREffects)

Final Voltage (V)

This is the voltage applied to the output amplifier stage. Theexample shown is a reading of 48 Volts. Used in conjunctionwith the final current reading will give an alternate methodof measuring output power. (Output power = V*I*0.7). 0.7is the efficiency of the output power amplifier.

Final Current (I)

This is the current consumed by the output amplifier Finalstage. The example shown is a reading of 8 Amps. Used inconjunction with the final Voltage reading will give analternate method of measuring output power as describedabove. This reading will change with output power setting,also antenna match will give different results.

FINAL CURRENT

FINAL VOLTAGE

FORWARD POWER

REVERSE POWER DEVIATION

Use the range selection switch(shown Left) to select the meterrange

Continued over

300250

100

020015050

50 75251000

DEVIATION kHzAMPS VOLTS(X10)

52.5100

7.5

PTEK

POWER Watts Deviation

This is the deviation in kHz caused by the program audio tothe carrier. The meter is peak reading and will vary inaccordance with the program (music speech etc.) The peaksshould not be more than 75kHz as indicated in this example.

Exciter Power Output Vs VSWR

0

50

100

150

200

250

300

350

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2Antenna VSWR

Pow

er W

atts

Power Output FM250EPower Output FM150EPower Output FM50EPower Output FM25E

C52

The transmitter frequency should be checked at lease once every 5 years. If the frequency offset is greater than +/- 1.5kHz,adjustments can be made by tuning C52; see diagram for location.

Frequency Adjustment

A qualified service technician should make adjustments. Alternatively the unit can be returned to the factory for service.

Circuit Description General The FM250E is housed in a 3U (5.25”), 19” rack-mounting case. Internally there are 4 PCB assemblies and 2 cased power supplies. Functional Two 24V power supplies are connected in series to provide 48V for the power amplifier and 24V of the exciter and fan. Audio inputs (SCA Composite and Mono) are connected directly to the exciter board, premphasis is applied to the mono channel only. These input are then summed together and feed to a veractor diode used to tune the VCO (voltage controlled oscillator). A sample of the VCO’s output frequency is used by a synthesizer to compare again a reference oscillator. This generates an error voltage which is used to tune additional veractor diodes in the VCO to maintain a constant frequency. The main output from the VCO is amplified up to 25W. The output from the exciter board is used to drive the power amplifier to 300W. Integral to the power amplifier is a harmonic filter used to reduce harmonics generated in the power amplifier to acceptable levels. This output is then feed back to the exciter board and on to the output connecter via a forward and reverse power detector. The exciter board also contains control circuitry, which levels the output power to a level set by a reference voltage. The detected forward power and reverse power are summed and compared to the reference voltage. The gain of the reverse power path is 10 times that of the forward power. This ensures that should the load be remove the forward power will be reduced to a safe level. The reference voltage used by the control circuit is generated by a microprocessor. This value can be changed by using the up/down control on the front panel or by remote contact closure from the rear panel accessory connectors. The microprocessor also feeds the frequency information to the synthesizer. Metering on the from panel is a multimeter, each function is selected by a rotary switch. The voltages for Current and voltage are provided by the PSU metering board, forward and revere voltages by the synthesizer board. All these voltages are also connected to the rear panel for remote metering. Mounted on the exciter board is a magnetically latched relay used for remote on/off functions. This requires only a momentary contact closure for either on or off. Cycling the AC power will not change the state of this relay.

FCC Compliance statement

THIS DEVICE HAS BEEN VERIFIED TO COMPLY WITH PART 73 OF THE FCC RULES.

Page 11

Pos Function

1 Remote on; Momentary ground to turn the unit on.

2 Remote off; Momentary ground to turn the unit off.

3 Forward Power DC indication 2.4V=12W

4 Reverse Power DC indication 2.4V=1.2W

5 Final Voltage DC indication V=Vsupply/10

6 Final Current 1A=0.1V

7 Raise Ground to Raise Output Power

8 Lower Ground to Lower Output Power

9 600 ohms balanced mono input

10 600 ohms balanced mono input

FM25E FM50E FM150E

Power

Output

(Watts)

Efficiency

(%)

Power

Output

(Watts)

Efficiency

(%)

Power

Output

(Watts)

Efficiency

(%)

25.0 52% 50.0 48% 150.0 57%

22.5 49% 40.0 42% 120.0 51%

20.0 47% 32.0 38% 96.0 45%

17.5 46% 25.6 33% 76.8 40%

15.0 44% 20.5 30% 61.4 35%

12.5 42% 16.4 26% 49.2 32%

10.0 33% 13.1 23% 39.3 28%

Efficiency V Output Power

Accessory connector

CA 95124

SAN JOSE

1814 SCHOOLDALE DRIVE

PTEK

10/27/2003

A

1OF1

C

SHEETSCALE

REVDWG NOFSCM NOSIZE

A

B

C

4 3 2 1

C

B

A

1234

BLOCK DIAGRAM

5

5

4

4

3

3

2

2

1

1

D D

C C

B B

A A

NOT USED ON EXCITERS

NOT USED ON EXCITERS

110853 <RevCode>

Schematic PA 300W 88 to 108MHz

B

1 2Monday, March 08, 2004

Title

Size Document Number Rev

Date: Sheet of

AGC2

AGC1

AGC1

AGC2

IPARF

IPARF

44V

44V

C430.01u

R1100

PRINTED

Q1 MRF150

R11100

Q2MRF150

C3639p

C862p

R12100

C31 0.01u

R20

470

C1224p

R21 10k

C1447p

R622

PRINTED

T2

PCB TRFMR

1 5

4 8

C471000p

R2100

L2

C3515p

C3415p

PRINTED

R4100

C150.01u

C4847u

C420.01u

D21N4148

C647p

R22100k

R5120

C947p

C32 0.01u

L3

C45

0.01u

T1

15

6

48

C3739p

C4633p

C71000p

Q3MRF171

C3947u

J12

CON20

1234567891011121314151617181920C44

0.01u

C160.01u

C1047p

L1

L4

D1

1N4148

PRINTED

R13100k

C50.01u

C20.01u

C3315p

C3839p

R7120

C1147p

C27120p

L5

C30 0.01u

R9100

R3100

R10100

44V IN

FWD PWR

RF OUT

REV PWR

RF IN

REV PWR

FWD PWR

5

5

4

4

3

3

2

2

1

1

D D

C C

B B

A A

REV PWRFWD PWR

To Front Pan Metering

Current & Voltage Metering

B

1 1Monday, January 09, 2006

Title

Size Document Number Rev

Date: Sheet of

0V IN

24V

24V

J1

12

12

R11 10k13

2

MTG21

C3 1000p

MTG11

R10 0.01

R52.4k

+

-

U1A LM324

3

21

411

R62.4k

R9 100

R8

4.7k

R12.4k

J2

CON14

123456789

1011121314

J4

12

12

C21000p

R4

2.7k

J3

CON14

123456789

1011121314

C10.01u

R7

3.3k

R3

10k

13

2

R22.4k

5

5

4

4

3

3

2

2

1

1

D D

C C

B B

A A

DOWNUP

110849 A

PCB ASSY FRONT PAN METERING

A

1 1Monday, March 08, 2004

Title

Size Document Number Rev

Date: Sheet of

SW112

123456

789

10

11

D1

OUT OF RANGE LO

SW2

21 3

D2

OUT OF RANGE HI

D3

REMOTE OFF

J1

1234567891011121314

A

M1

METER A

5

5

4

4

3

3

2

2

1

1

D D

C C

B B

A A

48V IN +

48V IN -

48V OUT+

48V OUT-

24VPSU

24VPSU

24V+24V+ 24V-24V-

48V +

48V -

24V +

EXCITER 88 to 108MHz

PSU METERING

FRONT PANNELMETERING

COMPOSITE IN

SCA IN

RF OUT

REMOTE ONREMOTE OFF

FWR PWR

FINAL VOLTAGEREV PWR

FINAL CURRENTRAISELOWER

MONO IN BALANCEDMONO IN BALANCED

AC INLIVE

AC INNeutral

AC INNeutral

AC INLIVE

<Doc> <RevCode>

<Title>

D

1 1Monday, March 08, 2004

Title

Size Document Number Rev

Date: Sheet of

J1

1234567891011121314

D1

11

J1

123456789

1011121314

J2BNC

1

2

J3BNC

1

2

J1

1234567891011121314

J4TYPE N

1

2

D2

JP1

1 1

J1

1234567891011121314

11

11

11

11

JP1

1 1

J5REAR TERMINAL BLOCK

12345678910

JP1

1 1

JP1

1 1

J6PLUG AC MALE

1 2

3

11

11

11

11

AC ON

1 2

11

FAN 24V

1 2

11