Specifications

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 than
2: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 output into an antenna and into a 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 an accessory balun.
12. Permit the use of long-wires of various
impedances. The accessory balun can be used
to match the higher impedance ranges.