Eton E1 manual Frequency Resolution, SSB Operation, Passband Tuning, Front Panel Lock Unlock

GETTING STARTED continued

E1 MANUAL

GETTING STARTED continued

Press the ‘SW BAND’ softkey to enter the shortwave band tuning mode. The SW portion of the display indi- cator will now be in reverse video. Now press the ‘SW BAND’ softkey a second time.

The display indicator will now appear as “SW BAND”, and the ‘METER’ number entry prompt on the display will be flashing. (See #8 on the LCD Display Description on page 18). At this point, you have approximately 3 seconds to do one of the following:

(1)You can enter a shortwave band ‘METER’ number with the ‘Direct-Key-Input’ keys. For example, key in ‘4', ‘1' for the 41 meter band.

(2)You can scroll through the available meter bands using the ‘TUNING’ knob or the ‘< SELECT >’ key, stopping on the desired ‘METER’ band. If you stop on a “METER” band for more than 3 seconds, the

FREQUENCY RESOLUTION

The E1 receive tunes in the following steps:

receiver will tune to that band, the “SW BAND” indicator will appear as “BAND“, and the shortwave band SW “METER” prompt will quit flashing.

To enter a shortwave band ‘METER' designator, press the ‘SW BAND’ softkey to display a flashing ‘METER' number entry prompt. The prompt will flash for approx- imately 3 seconds after the ‘SW BAND’ softkey is pressed. While it is still flashing, enter one of the listed two or three digit Band numbers corresponding to the desired ‘METER' band designator using the ‘Direct-Key- Input’ keys. While the ‘METER' annunciator is flashing, the ‘< SELECT >’ keys can also be used to step quickly from band to band. After selection of the ‘METER’ band, use the ‘TUNING’ knob or ‘< SELECT >’ keys to change the frequency, or press the ‘Direct-Key-Input’ keys to make a direct frequency entry.

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).

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- ing 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.

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.

Mode	Display *Resolution	Tuning *Resolution	< SELECT >
MW AM:	10 Hz	10 Hz	10 kHz /
	100 Hz	100 Hz	9 kHz
	1 kHz	1 kHz
MW SSB:	10 Hz	10 Hz	10 kHz /
	1 kHz	1 kHz	9 kHz
LW & SW AM	10 Hz	10 Hz	5 kHz
	100 Hz	100 Hz
	1 kHz	1 kHz
LW & SW SSB	10 Hz	10 Hz	5 kHz
	1 kHz	1 kHz
FM	10 kHz	20 kHz	100 kHz
	100 kHz	100 kHz

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

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

* Selectable using ‘FAST’ button.

FRONT PANEL LOCK (UNLOCK)

All front panel keys (with the exception of the ‘CLEAR / LOCK’ key), as well as the ‘TUNING’ knob can be locked if desired. First, be sure the E1 receiver is not in T.SCAN or SEEK mode. Press and hold the ‘CLEAR/LOCK’ key which is one of the ‘Direct-Key- Input’ keys. The “LOCK” and “TUN LOCK” annuncia- tors will appear indicating the front panel controls are locked out. ‘‘VOLUME’, ‘BASS’, ‘TREBLE’, and ‘SQUELCH’ are still functional. Press and hold the ‘CLR/LOCK’ key to unlock. The “LOCK” and “TUN LOCK” annunciators will disappear, indicating the front panel controls are once again active. The ‘CLEAR /

LOCK’ key may be used even when the radio is off to lock the ‘POWER’ key to prevent accidental power acti- vation.

AM SYNCHRONOUS OPERATION

For general tuning and listening, normal AM is best. If, however, the received signal sounds distorted, or inter- ference from adjacent stations is present, AM synchro- nous should be engaged. The synchronous detector in your receiver can greatly reduce the severe audio dis- tortion that can occur due to signal fading. The detec- tor also permits selectable tuning to either the upper or lower sideband portion of an AM signal. Since most

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 tuning has stopped. The PBT control can sometimes help in reduc- ing adjacent interference. For more details see “PASS- BAND 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.

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

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