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4. automatic antenna tuner, The at unit at-440 is required for this function.), 5. dual digital vfo's – Kenwood TS-440S User Manual

Page 17: 4. automatic antenna tuner 3-5. dual digital vfo's

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• Subaudible tone

An optional subaudible tone unit TU

-8

is available for

installation in the TS-440S for accessing 10 meter FM

repeaters.

This

tone

is

activated

whenever

the

TS-440S is in the SPLIT mode.

3-3-4. AM mode

1. Set the Meter switch to PWR.

2. Set the MODE key to AM.

3. Place the Standby switch to SEND.

4.

Adjust the CAR control so that the meter indicates

25 watts.

5. Place the Meter switch to ALC.

6

.

Adjust the MIC gain control so that the meter

deflection does not exceed ALC zone on voice

peaks.

3-5-1. Why two VFO's

Occasionally

DX

stations

will

utilize

an

operational

procedure known as split frequency operation. When

the DX station is in this mode he will be transmitting

on one frequency and receiving on another. This is

done in order for the DX station to be able to recog­

nize the calls of stations during pile-ups.

Older transceivers required the use of an external VFO

to allow this split frequency operation. The TS-440S,

thru the use of microprocessor controls, effectively pro­

vides two separate VFOs in the same package. Several

different controls and switches have been provided to

increase the operators convenience when faced with

this type of operation. The use of these controls is dis­

cussed below.

3-4. AUTOMATIC ANTENNA TUNER

(The AT unit AT-440 is required for

this function.)

The automatic antenna tuner operates within the

amateur radio bands from 3.5 thru 29.7 MFIz.

1.

Ensure that an antenna designed for use within the

band you intend to operate on is properly connect­

ed to the antenna terminal.

2. Set the AUTO/THRU switch to the AUTO position.

3.

Place the AT TUNE switch to the ON position. The

AT TUNE indicator will light and the tuner will be­

gin tuning. Then the CW mode indicator will light.

4.

After a short period the AT TUNE indicator will go

OFF and the motors will stop turning.

5. Place the AT TUNE switch to OFF.

6

. Tuning is now completed. You may now carry out

normal communications.

Notes:---------------------------------------------------------------------------

1.

When the AT TUNE switch is ON and the AT indi­

cator lights but then goes out immediately it is an

indication that the antenna was not that far off

resonance and that tuning has been completed.

2 . Normal operation is not possible until the AT TUNE

switch has been turned OFF.

3 . If the motors do not stop turning after approximately

30 seconds, place the AT TUNE switch to OFF, and

then back to ON again. The tuner will attempt to

tune again, and should find a good match. If the

tuner will not stop after several tries it indicates

some

problem

exists

with

the

antenna

system.

Readjust the antenna and feedline before attempt­

ing to tune again.

3-5. DUAL DIGITAL VFO's

Operational convenience can be enhanced thru the use

of both VFO A and VFO B.

3-5-2. Split frequency

(a) A = B switch

Depressing this switch causes the data contained

in the inactive VFO (the VFO that is not currently

being displayed) to change to the same data con­

tained in the active VFO (the one currently dis­

played).

Both

the

frequency

and

mode

are

changed.

For example: VFO A is set at 7 MHz in LSB, and

VFO B is 21 MHz in USB. VFO A is the active VFO

(show on the display). Depressing the A = B switch

will cause VFO B to change to 7 MHz in LSB.

(b) A/B switch

Allows selection of the desired active VFO. Each
time this switch is depressed the active VFO will

alternate between VFO A and VFO B.

(c) SPLIT switch

Allows the use of one VFO for transmit, and the

other for receive (Split Frequency operation). For

example: VFO A is the active VFO, and VFO B is

the inactive VFO. Depressing the SPLIT switch will

cause the TS-440S to receive on VFO A and trans­

mit on VFO B. The mode of reception and trans­

mission will follow the mode contained in the

appropriate VFO memory. It is possible to work
cross band, cross mode if desired.

To avoid confusion during contest, or pile-up oper­

ations we recommend using VFO A for receive and

VFO B for transmit.

(d) T-F SET switch

Depressing this switch will allow you to rapidly set

or check the transmit frequency, during SPLIT

operations, without the need of actually trans­

mitting.

This switch is especially convenient when you are

trying to locate the transmit frequency of the sta­
tion currently in contact with the DX station, since

15