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Section 5 – OPERATION NOTES
AND ACCESSORY CONNECTION
EXAMPLES
OPERATING THE AUTOMATIC
ANTENNA TUNER (IF INSTALLED)
First, enter the menu system by pressing
MNU and assure that line item AUTO
TUNER is set to ON.
The matching range of the tuner is
approximately 6 to 800 ohms or a 10:1
maximum SWR up to 30 MHz. The
automatic antenna tuner will not operate on
the 50 MHz (6 meter) band.
While the tuner will tune many HF antenna
installations, some multi-band wire antennas
are capable of exhibiting a feedpoint
impedance of several thousand ohms and
are unsuitable to be tuned with the
autotuner. An example would be an 80
meter 1/2 wave dipole fed on 40 meters
which would exhibit a feedpoint impedance
of several thousand ohms. The ARRL
Antenna Book and antenna design websites
like W4RNL's
www.cebik.com
provide a wealth of useful information about
effective antennas for use with OMNI-VII.
To use the internal tuner, press TUNE. A
carrier at approximately 20 watts output
power will be transmitted and the tuner will
actuate. It takes 1 to 3 seconds to tune
depending on frequency and load
impedance.
Once tuned, the legend TUNED will appear
at the upper left corner of the screen. To
bypass the tuner, press TUNE again and the
legend will change to BYPASS.
The tuner will usually stop at a value of 1.5:1
SWR or lower. Occasionally it may present
a slightly higher SWR after tuning. This is
normal, and the transceiver will still transmit
at full output power with no foldback.
The tuner has 100 tune memories. The user
must hit TUNE each time he returns to a
previously used frequency to recall the tuner
settings. Instead of taking 1 to 3 seconds to
tune, a previous frequency in the tuner
memory will tune in a shorter amount of
time. If user changes bands and does not
hit tune before transmitting, the tuner is in
588 manual
Part #74409
Printed in USA
bypass mode and SWR is that of the
antenna connected.
The automatic antenna tuner will operate on
either ANT 1 or ANT 2 depending on which
has been selected with the front panel ANT
button. The tuner will NOT memorize
settings per antenna, only per frequency for
the last antenna used.
If an attempt is made to use the autotuner
on the 50 MHz band, the status message
NO AUTO 6M will appear at upper right on
the screen. To remedy, go into the menu
and turn the autotuner off. The TUNE
and/or PWR buttons can then be used to
generate a carrier on the 50 MHz band.
In some circumstances, it may be possible
to present a load outside the 6 to 800 ohm
matching range to the autotuner. The tuner
will be unable to match an impedance
outside 6 to 800 ohms, and the screen
message TUNE FAILED will appear on the
screen at top right. The tuner will
automatically switch to BYPASS if the TUNE
FAILED message appears.
CONNECTING AN EXTERNAL
LINEAR AMPLIFIER
can also
There are three possible types of
connections for a linear amplifier depending
on whether your amplifier is a QSK linear
amplifier and whether, if so, it employs the
use of a full break-in keying loop.
Non-QSK linear amplifiers or QSK linears
that do not employ the use of a keying loop
are keyed from the AMP KEY jack. Connect
the PTT keying line of your linear amplifier to
the AMP KEY jack using a shielded cable
with RCA-style male phono connectors at
each end. The AMP KEY keying output is a
open collector transistor output. See the
warnings about attaching older linear
amplifiers that may have high voltage
present on the PTT line before using your
amplifier.
Some QSK linear amplifiers incorporate the
use of a full break-in keying loop. Ten-Tec
transceivers and linear amplifiers use a full
break-in keying loop to assure proper
sequencing of the keying between the radio
and the amplifier.
To use the OMNI-VII with a full break-in
linear amplifier incorporating a keying loop,
Second release – August 2007
27
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