Eton E1 - Manual (Page 13)

25
GETTING STARTED continued
E1 MANUAL
temporarily until the system once again locks on to the
desired carrier.
FM OPERATION
FM reception is perhaps the easiest mode to use on
the
etón E1 receiver. The AGC and BANDWIDTH set-
tings are not used in FM. In fact, all of the function
softkeys along the bottom edge of the display except
the ‘MENU’ softkey have no function on FM and the
labels on the display for these softkeys disappear.
Attempting to use one of these softkeys will result in
an ‘ERROR’ beep. All FM stations in the U.S. end in an
odd 100 kHz, i.e. 97.7 MHz, and are spaced 200 kHz
apart. The
etón E1 receiver has the ability to tune in
20 kHz steps to allow tuning in between stations to
help eliminate interference to weaker stations that
could be covered up by stronger adjacent stations.
Additionally, when headphones are used, or if the LINE
OUT jack is fed into an external stereo sound system,
true stereo reception is possible. The ‘STEREO’ indicator
on the display will appear when a stereo station is
tuned in. ‘MONO’ will appear in this location if the
transmitting station is not in stereo, if no signal is
being received, or if MONO is selected from the AUDIO
SETTINGS menu. To select between STEREO and
MONO from the AUDIO SETTINGS menu, proceed as
follows:
• Press the ‘MENU’ softkey.
• Press the ‘Direct-Key-Input’ ‘2' key or press ‘MENU’
two more times. This will access the AUDIO SET-
TINGS menu.
• Press the ‘Direct-Key-Input’ ‘1' key to cycle between
MONO and STEREO.
When STEREO is enabled, the receiver will automati-
cally switch to stereo and provide left and right audio
from the HEADPHONE and LINE OUT jacks when a
stereo FM signal is being received. If the headphones
are removed while listening to a stereo broadcast the
receiver will provide monaural audio from the internal
or an external speaker.
AGC OPERATION
The
etón E1 receiver provides the ability to select a
SLOW, FAST, or AUTO AGC setting. Each of the three
settings will permit automatic control of the receiver’s
gain thereby producing a constant audio output free of
distortion. Generally, the SLOW AGC setting is pre-
ferred for reception of AM and SSB signals. The FAST
AGC setting allows more rapid automatic receiver gain
adjustment to quickly fading signal levels. The AUTO
setting provides FAST AGC while tuning between sta-
tions to prevent the user from missing weak stations
between strong ones. However, once a station is tuned
in, it automatically switches to SLOW for smoother
audio output. The AGC does not function in the FM
mode.
MICROPROCESSOR RESET
A power-up reset routine will be activated anytime
after the receiver COMPLETELY loses power, from inter-
nal batteries and external DC input. However, short
term power failures of up to 10 minutes are masked by
an internal back-up capacitor. This will allow ample
time for battery replacement without loss of the inter-
nal clock. Note: Any programmed memory channels
and timer settings will NOT be lost under a power-up
reset due to the memory design of the
etón E1 receiv-
er.
BEEP TONES
The
etón E1 receiver responds to nearly all key depres-
sions with an audible beep unless the beep has been
disabled by means of menu entry 2 in AUDIO SET-
TINGS menu. This menu is accessed by pressing the
‘MENU‘ softkey three times, or by pressing the ‘MENU’
softkey once to access the MAIN MENU, and then
pressing the ‘Direct-Key-Input’ ‘2' key. No beep is gen-
erated under any condition for depressions of the “ <
SELECT >” keys when in VFO mode. Beep tones indi-
cate the following:
• One short tone for a key depression.
• One short, high tone when storing a MEMORY,
COUNTRY, or XM FAVORITE channel.
• One long, low tone for any illegal key depression.
• Four quick beeps at one minute intervals if batteries
are installed, an external power source is connect-
ed, and the external power is lost. This feature must
be enabled from AUDIO SETTINGS menu item 3.
Note that the volume of the beep tones is controlled
by the ‘VOLUME’ control, so if the ‘VOLUME’ control is
turned all the way down, no beep tones will be heard.
24
all AM (LW, MW and SW) broadcasting generally uses
double-sideband transmission, detection of either of
the two sidebands results in full reception of the trans-
mitted information. The selectable sideband tuning and
detection not only aids reception by permitting tuning
to the stronger or less distorted sideband, but also per-
mits rejection of the sideband nearer to the interfering
signal(s).
For Example
The synchronous detector will lock to the strongest sig-
nal that is within the IF passband when it is activated.
Most of the time, the strongest signal will be the carri-
er of the desired signal. First, be sure the main tuning
is set to within 1 kHz of the desired station's transmit-
ting frequency. Press the ‘AM’ softkey after AM is
already selected to activate synchronous operation.
‘AM SYNC’ will briefly flash on and off above the ‘AM’
softkey and will then stop flashing as the AM SYNC
detector locks on to the carrier frequency.
If adjacent channel interference or any other undesired
signal is sufficiently strong, the synchronous detector
may lock to it instead. In that case, press the ‘AM’ soft-
key again to turn the synchronous detector off, and
repeat the tuning process. For severe cases of fading,
set the bandwidth to 4 kHz by pressing the ‘BW’ soft-
key until 4.0 kHz appears above the ‘BW’ softkey. If
interference is present, repeatedly press the ‘SSB’ soft-
key to select whichever of USB, DSB or LSB produces
the least interference once ‘AM SYNC’ has been select-
ed. If the interference is sufficiently severe to prevent
reception, select a narrower IF bandwidth and retune
to the desired signal. After reception is obtained, select
a wider bandwidth and/or alternate sideband if
desired. When ‘AM SYNC’ has been activated, moving
the ‘TUNING’ knob will cause the
SYNC circuit to momentarily disengage (indicated by
“AM SYNC” flashing), then back on again when tun-
ing has stopped. The PBT control can sometimes help
in reducing adjacent interference. For more details see
“PASSBAND TUNING” in the next column.
AM SYNC will not operate properly on intermittent
transmissions such as those encountered on CB radio
band. For those types of transmissions, use the AM
mode. Press the ‘AM’ softkey to turn the synchronous
detector off before selecting LSB or USB modes for SSB
operation.
GETTING STARTED continued
SSB OPERATION
Tuning in a single sideband (SSB) signal can be some-
what frustrating for the first time listener. In either of
the E1 receiver’s SSB modes, LSB (lower sideband), or
USB (upper sideband), the receiver will select the 2.3
kHz bandwidth automatically. Generally LSB is used
below 10 MHz and USB is used above 10 MHz. When
initially tuning in the desired station, tune slowly. If the
station is unintelligible, try the other sideband, again
tuning slowly. A station tuned in on the wrong side-
band is totally unreadable but a station mistuned on
the correct sideband may sound like ‘Donald Duck’.
Further tuning will result in a more normal voice pitch.
Always start with the ‘PBT’ off when initially tuning
SSB signals.
PASSBAND TUNING
The passband tuning (PBT) feature allows for moving
the IF passband of the receiver relative to the detector
BFO (beat frequency oscillator) when operating in SSB
mode. This can be quite useful in receiving a weak sig-
nal in the presence of nearby interference. Passband
tuning is available on the LW, MW, and SW bands, and
is engaged or disengaged by pressing the ‘PBT’ soft-
key. PBT status is shown on the display directly above
the softkey.
When it is engaged, the displacement in kilohertz from
the BFO frequency is shown directly above the softkey
label, and the degree of IF passband displacement is
controlled by the PBT knob. When PBT is disengaged,
there will be no information displayed above the ‘PBT’
softkey label, and the PBT knob will have no affect.
To use PBT, tune in the desired SSB signal for best
audio quality as you normally would with PBT off. You
will find that PBT is most effective when the 2.3 kHz IF
bandwidth is used. Then press the ‘PBT’ softkey and
adjust the PBT knob for the best compromise between
minimum adjacent signal interference and acceptable
audio quality of the desired signal.
Enhanced SSB, when engaged (RADIO SETTINGS
Menu, item 1), provides 30 dB of additional rejection
of the undesired sideband through the use of audio
phasing circuitry. Using this in combination with
Passband Tuning can effectively narrow the IF to less
than the 2.3 kHz IF filter.
PBT also functions in AM and AM SYNC modes, but in
these modes it acts primarily as a frequency offset,
which can also be accomplished with the ‘TUNING
knob. When operating in AM SYNC mode, tuning the
PBT knob will cause ‘AM SYNC’ to flash on and off