DRAKE R8B Owner's Manual download pdf (Page 20)

LIST

A-B

TIME

CARR

TUNE

VFO A = B

A = B

PRE ATTN

ANT 1 2 VHF

 

AGC S F

NOTCH

NB N W

NAME



12 ON OFF

TIMER

STEP

CLK/FREQ

LOCK

TUNE

SCAN

NOTCH TONE

SCAN

MEM

0.5

AUTO CW RTTY

BANDWIDTH

MODE

LIST

A - B

SEEK

TIME

CARR

CLK

LAMP

BEEP

DEL

V M

M V

SQUELCH

PASSBAND

OFFSET

VOL RF

MIN

0

UNITS

DECIBLES

SIGNAL

M/KHz

MEM

CLR

Getting Started cont'd. 18

TONE

CENTERED

NOTCH

CENTERED

VOLUME

COUNTER-CLOCKWISE

SQUELCH

COUNTER-CLOCKWISE

PASSBAND OFFSET

CENTERED

RF GAIN

CLOCKWISE

FIGURE 10

If the default 'AUTO' settings have been programmed by

the user, then those particular settings are recalled. Gen-

erally, LSB is used below 10 MHz and USB is used above 10

MHz.

First, be sure the PASSBAND OFFSET control is centered.

When initially tuning in the desired station, tune slowly. If

the station is unitelligible, try the other sideband again

tuning slowly. A station tuned in on the wrong sideband

is totally unreadable but a station mistuned on the right

sideband may sound like "Donald Duck". Further tuning

will result in a more normal voice sound. Once the station

is tuned in, the PASSBAND OFFSET can be used to alter the

audio response of the received SSB signal. Refer to

PASSBAND OFFSET OPERATION for details. Additionally, if

adjacent stations are causing interference, the 1.8 kHz

bandwidth filter may be selected in conjunction with the

PASSBAND OFFSET to further reduce or eliminate interfer-

ing signals.

FM OPERATION

Frequency modulation (FM) is perhaps the easiest mode

to use on the receiver. When the FM mode is selected the

receiver defaults to PRE only. No AGC or BANDWIDTH

settings are used in FM mode. In fact, attempting to

activate these buttons will result in an error beep. Addi-

tionally, NB, NOTCH, PASSBAND OFFSET, and RF GAIN

controls are not used.

Most FM transmissions are above 29 MHz and are gener-

ally amateur radio in nature. A very active frequency,

when conditions permit, is 29.660 MHz.

Peculiar to FM transmissions is the fact that a stronger

signal on the same frequency or close to the same

frequency will completely cover up a weaker signal. Also,

there are no controls to help reduce or eliminate an

interfering signal. This is not a fault of the receiver but of

the FM mode of transmission. However, to help in elimi-

nating the background hiss, the SQUELCH control may be

used to quiet the receiver during periods of no signal.

NOISE BLANKER

The NOISE BLANKER NB provides two settings which will

reduce or eliminate much noise interference encoun-

tered. The



(or narrow) setting is for short duration, high

impulse noise such as automotive ignition noise. The

W



(or

wide) setting is to reduce longer duration impulses.

Unfortunately, there exists no blanker capable of eliminat-

ing all possible noise either atmospheric or man-made.

Another side effect of the NOISE BLANKER use is on AM

signals. Occasionally, if a strong AM signal is tuned in and

the NOISE BLANKER is engaged, blanking can occur on

modulation peaks causing a popping or breaking up of

the audio. If this is noticed, be sure the NOISE BLANKER is

off.

CW OPERATION

For general tuning in CW mode, the 1.8 kHz bandwidth is

recommended since the 0.5 kHz bandwidth is very nar-

row. When the desired signal is found, tune the receiver

until an approximately 800 Hz audio note is heard, then

select the 0.5 kHz filter. If interference is present, the

passband offset can be employed to reduce or eliminate

the interfering signal.

RTTY OPERATION

In RTTY mode, the receiver selects the user programmed

bandwidth (1.8 kHz recommended) filter and positions it

for the 2125 Hz mark and 2975 Hz space high tone group.

When receiving other shifts such as 425 Hz or 170 Hz, the

PASSBAND OFFSET may need to be adjusted to pass both

tones equally. Additionally, the selected IF bandwidth

should not be smaller than the shift of the received signal.

Therefore, the 0.5 kHz bandwidth filter can not be used

when receiving a 850 Hz shift RTTY signal but could be

selected for a 425 Hz or 170 Hz shift RTTY signal.

SSB OPERATION

Tuning in a single sideband (SSB) signal can be somewhat

frustrating for the first time listener. With the 'AUTO' band-

width selected in either of the receiver's SSB modes, LSB

(lower sideband) or USB (upper sideband), the receiver

will select the 2.3 kHz bandwidth, 10 Hz tuning steps and

Slow AGC setting.

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DRAKE R8B Owner's Manual Page 20

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