DRAKE MN2700 User manual

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CHAPTER I
1.1.
1.2.
CHAPTER ll
2.1.
2.2.
2.3.
2.4.
CHAPTER I11
3.1 .
3.2.
3.3.
3.4 .
3.5 .
3.6.
3.7.
TABLE OF CONTENTS
INTRODUCTION .......
PAGE
................... 1.1
Description ....................................
...................................... Specifications
INSTALLATION
........................................... ........ 2.1
........................................................... Unpacking 2-1
Location ............................................................. 2.1
Requirements ........................................................ 2.1
Antenna Connections ................................................ 2.1
OPERATION .......................................... ......
Front Panel Controls ..................................................
Rear Panel Connections .............................................
Use of the Drake B-1000AccessoryBalun ................................
Operating Procedure- .................................................
0ff.the.Air Tuning ....................................................
Reflected Power .....................................................
Use with Transceivers or TIR Combinations ..............................
............
. CHAPTER IV MAINTENANCE

Fig. 1-1 MN2700 Matching Network

CHAPTER I
INTRODUCTION
4. Match an antenna to a transmitter having
The typical modern transmitter or high-power
amplifier has either a pi-network tank circuit or a
broadband transformer output and will work into
resistive loads of 50 to 75 ohms with Voltage
Standing Wave Ratios (VSWR)of 2:l or less. This
resistive load can only he achieved with a resonant
antenna; thus, for multiband operation, multiple
antennas are required. Space and cost considera-
tions render this solution impractical for most
amateurs. In addition, many singleband antennas
will not maintain less than2:l VSWR across the en-
tire band. The MN-2700 impedancematching net-
work can:
1. Measure feedline VSWR, then reduce the
VSWR at the transmitter output to
1:l.
2. Monitor transmitter power output in watts
directly and continuously.
3. Attenuate 2nd harmonic output from a trans-
mitter by 25 to 35
dB; thus it may eliminate
the need for a low-pass
TVI filter.
fixed loading.
5. Give optimum match with multiband
antennas.
6. Precisely match a transmitter to an antenna
across a complete amateur band.
7. Permit off the air transmitter tuning using a
dummy load.
8. Eliminate the necessity of retuning the
transmitter when switching from "barefoot"
to linear amplifier operation since the
transmitter always "sees" 50 ohms resistive.
9. Help localize trouble by comparing trans-
mitter outputinto anantenna and intoa dum-
my load.
10. Allow antenna comparisons with the use of
the internal antenna switch.
11. Permit the use of open-wire feedline antenna
systems, with the use of anaccessory balun.
12. Permit the use of long-wires of various
impedances. The accessory balun can be used
to match the higher impedance ranges.

1-2. SPECIFICATIONS. Power Capability:
Frequency Coverage:
Input Impedance:
Load Impedance:
Balanced Feedlines:
Long-WireAntennas:
1.8 to 30 MHz. Band
Switch marked for 160, Meter:
80, 40, 20, 15, and 10
meter amateur bands;
however, frequency Wattmeter Accuracy:
coverage between
amateur bands is possible Insertion Loss:
by using the nearest band
positions with a small Dimensions:
reduction in matching
capability.
50 ohms (resistive).
50 ohm coaxial with
VSWR of 5:l or less at
anyphase angle (3:l on 10
meters).75 ohm coaxialat Front Panel Controls:
a lower VSWR can be
used.
With the Drake B-1000
accessory balun, tunes
feed point impedances of
40 to 1000 ohms, or 5:l
VSWR referenced to 200
ohms (3:l on 10 meters). Rear Panel
Feed point impedances up Connectors:
to 5:l VSWR referenced
to 50 ohms. Also, 5:l
referenced to 200 ohms
with the Drake B-1000 ac-
cessory balun (3:l on 10
meters).
1000 watts average
continuous duty, 2000
watts PEP
Reads VSWR or forward
power, 0-200 watts or
0-2000watts.
f 5% of reading + 1%of
full scale.
0.5 dB or less on each
band after tuning.
Height: 4-17132 in. (11.5
cm)
Width: 13-3/32 in. 133.26
cm)
Depth: 13 in. (33 cm) in-
cluding connectors.
Weight:
11 lbs. (5kg)
Provide for the adjusb
ment of resistive and
reactive tuning, antenna
switching, band switch-
ing, VSWR calibration,
and selection of watts or
VSWR functions of the
meter.
The rear panel has four
type SO-239 connectors
(one for input and 3 for
outputs), three screw ter-
minal connections (for
long-wire and open-wire
feeder systems), and a
ground post.

CHAPTER ll
INSTALLATION
Carefully remove the MN-2700 from the shipping
carton andexamineitfor evidenceof damage.Ifany
damage is discovered, immediately notify the
transportation company that delivered the unit. Be
sure to keep the shipping carton and packing
material for the transportation companytoexamine
if there is a damage claim. Keeping these items is
recommended in any case, since having them
available makes shipment of the unit much easier
shoulditeverbe necessary toreturnittothefactory
3. REQUIREMENTS.
Connect the RF output of your transmitter or
amplifier to the XMTR connector of the MN-2700,
using 50 ohm coaxial cable such as RGdlU. Cable
length is not critical. In installations using a
transceiver or transmitter-receiver combinations,
the matching network should be the last item the
out-goingRF signalpasses through before entering
the feedline to the antenna. The effects of this on
receiver operation will be discussed
in Chapter 111,
Operation, of this manual.
for service. Connect the EXT GND post of the matching net-
work to the station ground with a short piece of
NOTE heavy braid.
Fill out theenclosedregistration card and
return it to the factory within 10 days of
2.4. ANTENNA CONNECTIONS.
purchase to insure registration and
validation of the warranty. Antennas such as beam antennas, single band
dipoles, trap dipoles, and verticals fed with coaxial
cable should be connected to the rear oanel connec-
-9-2 LOCATION.
tors marked ANT 1 or ANT 2.
-
Connectend-fedlong-wireantennastotherear panel
TheMN-2700will work properlyin almost any loca- screw terminals labeled
LW3 or LW4. A good RF
tion. Select a location on the operating table that ground shouldbe connected to the
EXT GND post.
will allow yoq to reach the control knobs easily. Antennas fed with balanced feedline should be con-
Figure
2-1 illustrates recommendedviewingoptions nected as explained in Chapter 111, Section
3-3 of
using the hardware furnished with the unit. this manual.
--- STANDARD
I
-
1, \ -4-
- OPIIONAL ftfl
~H,E,,,AL
rruo lox 14x 5/8 LONG
IUPPLI€O WITH UNlI
Fig. 2-1 Viewing Angle Options

, .
Fig. 3-2 Rear Panel Connections