Specifications

CHAPTER Ill
OPERATION
3-1. FRONT PANEL CONTROLS. (Figure 1-1)
VSWR SET Control:
Varies the sensitivity of the VSWR sensing
circuitry.
Meter:
Displays either forward power in watts or
VSWR as selcted by meter switches.
VSWR SET Switch:
Used
to calibrate the meter for VSWR measure
ments.
VSWR READ Switch:
Causes meter to indicate VSWR.
200 and 2000 Watt Switches:
Causes meter to indicate forward power, either
200 or 2000 watts full scale.
ANTENNA Switch:
Selects the desired antenna and grounds all
unused antenna terminals. Positions are provid-
ed for Dummy Load (which can also be used for
an additional antenna or as a grounding posi-
tion for antennas
1 through 4), 2 coaxial-fed
antennas
(1,2) and two long-wire antennas (3,4
without accessory balun). With accessory
B-1000 balun, balanced
feedline capability or
1:l and 41 match to long-wire antennas are
available.
BAND Switch:
Selects the fixed capacitors and inductors for
each band. In the DIRECT position, bypasses
the matching network and connects the RF
through the meter circuitry directly to the
antenna selected.
REACTIVE Tuning:
Tunes out the series reactive component of the
antenna impedance.
Reactive Range Switch:
Switches in additional fixed capacity to provide
additional reactive tuning range.
RESISTIVE Tuning:
Varies the resistive component of the MN-2700
output impedance to match the series resistive
component of the load.
Resistive Range Switch:
Switches in additional fixed capacity to provide
additional resistive tuning range.
3.2 REAR PANEL CONNECTIONS. (Figure 3-2)
XMTR Jack:
50-239 socket for input from the transmitter
DL Jack:
50-239 socket for the connection of a dummy
load (or another coaxial fed antenna).
ANT
1-and ANT 2:
50-239 sockets for 2 separate coaxial fed
antennas.
LW3 and LW4:
Screw terminals for two
longwire antennas,
when used without the accessory balun
(1:l im-
pedance ratio to matching range of network).
Numbers correspond to ANTENNA selector
switch position.
3.3. USE OF THE DRAKE B.1000 ACCESSORY
BALUN
Installation:
Remove the three screws at terminals marked
LW3, LW4, NC and then reinstall these screws
through the holes in the balun board to the
matching terminals on the MN-2700. Also, in-
stall the two mounting screws
in the other two
corners of the balun board
to the MN-2700.
Balanced Feedlines:
The two wires of the balanced feeders are con-
nected on the top of the balun board, under the
heads of terminal screws marked BAL and
BALlLW(1:l or 4:l). The ANTENNA selector
switch is placed in position 3 when this antenna
system is used.
Long-Wire Antenna Using Balun:
(Cannot be used when balanced feeders are at-
tached.) Connect the
longwire to the terminal
marked
BALILW (1:1 or 41). In ANTENNA
switch position 3, the antenna will be matched
with a
1:l impedance ratio. In position 4, the
antenna will be matched with a
4:l impedance
ratio, providing for a higher impedance range
matching capability.
It is absolutely necessary
to have a good RF ground.