7 OPERATING AIDS

AUTOMATIC ANTENNA TUNER

You have the choice of using the internal tuner, an external AT-300 tuner, or both.

Note:

The antenna tuners will not tune outside the authorized transmit limits of Amateur bands.

If an external AT-300 tuner is connected, the internal tuner is bypassed when the ANT 1 connector is selected. The AT-300 cannot be used with the ANT 2 connector.

When tuning in CW mode, the SWR meter may deflect upscale momentarily. This is not a fault.

If using Full Break-in CW, the internal antenna tuner can be bypassed completely or can be in-line for both transmitting and receiving. Even when OFF is selected via Menu No. 08 (RX AT), received signals pass through the antenna tuner. To protect the antenna tuner relay, the tuner cannot be used only for transmitting.

PRESETTING (INTERNAL TUNER ONLY)

After each successful tuning session, the Preset function stores the data for the position of the tuning capacitors on each band. Then, if the frequency is changed while the internal tuner is switched ON, this function automatically positions the capacitors without need for retuning. After changing bands, the Preset function activates for the newly selected band.

A different set of data is stored for each of the

18 antenna tuner bands (see table) and for each antenna connector (ANT 1 and ANT 2). Therefore, enabling the other antenna connector by pressing the [ANT] button may also cause the Preset function to activate. If no Preset data exists for a particular band/ antenna combination, then the default data for 50 is stored.

Presetting does not activate while transmitting. For split-band operation, even if Menu No. 08 (RX AT) is ON, the antenna tuner is bypassed while receiving. Also, at all times, presetting is only done for transmit frequencies.

PRESET BANDS FOR INTERNAL TUNER

INTERNAL TUNER

Note: Setting Menu No. 33 (TUN.WIDE) to OFF to select an SWR 1.2:1 reduces internal tuner losses. This setting is best.

1Press [THRU/AUTO].

“– AT – TX” lights. If Menu No. 08 (RX AT) is ON, then “– AT – TX RX” lights indicating that the tuner is in-line while transmitting and receiving. In this case, prior to tuning in Step 2, received signals are attenuated and the receiver sensitivity is lowered.

AGC AUTO

LSB

If the tuner has not adjusted itself yet for the selected frequency, then AT TUNE lights, and Preset tuning begins. Signals pass through the antenna tuner during this time. If Menu No. 08 (RX AT) is OFF, the antenna tuner is bypassed. The AT TUNE light goes out when presetting is completed. You cannot transmit while presetting is in progress.

AT TUNE

If Preset data exists, the next step cannot be done until the transceiver completes the Preset tuning.

2 Press [AT TUNE].

• To cancel tuning for any reason, press

[THRU/AUTO] or [AT TUNE].

• If the Preset tuning is aborted by pressing

[AT TUNE], the new temporary data will be used,

but this new data does not update the stored

Preset data. Also, the new temporary data will be

lost if the operating band is changed. Return to

the stored Preset data by pressing

[THRU/AUTO] OFF and then ON again.

Band

Range

No.

(MHz)

10.030 ~ 1.85

2 1.85 ~ 2.01

3 2.01 ~ 3.525

4 3.525 ~ 3.575

5 3.575 ~ 3.725

6 3.725 ~ 4.49

7 4.49 ~ 7.03

8 7.03 ~ 7.1

9 7.1 ~ 7.49

Band

Range

No.

(MHz)

107.49 ~ 10.49

1110.49 ~ 14.1

1214.1 ~ 14.49

1314.49 ~ 20.99

1420.99 ~ 21.15

1521.15 ~ 21.99

1621.99 ~ 25.49

1725.49 ~ 29

1829 ~ 30

• AT TUNE lights and stays lit while the tuner

tunes. When the light goes out, the tuner has

successfully matched the transceiver to the

antenna system with an SWR less than the value

set in Menu No. 33 (TUN.WIDE). You can begin

operating.

• If tuning doesn’t finish within about 20 sec, an

alarm sounds. You may stop the alarm and the

tuning by pressing [AT TUNE]. The alarm can be

either a triple beep or the Morse code “CHECK”

depending on the Menu No. 37 (WARN. BP)

setting.

• After each successful tuning, the Preset data is

updated.

Note: The lower limit is inside the band in each case; the higher limit is inside the next higher band. For example, 14.1 MHz is in Band 12 whereas 14.49 MHz is in Band 13 (exception: 30 MHz is in Band 18).

Note:

While receiving with Menu No. 08 (RX AT) ON on frequencies outside the Amateur bands, sensitivity is lowered.

It’s a good practice to press [AT TUNE] after changing bands to ensure the tuner has tuned for minimum SWR.

49

Page 55
Image 55
Kenwood TS-870S instruction manual Automatic Antenna Tuner, Presetting Internal Tuner only, Preset Bands for Internal Tuner

TS-870S specifications

The Kenwood TS-870S is a distinguished transceiver that stands out in the world of amateur radio, particularly for enthusiasts who seek a blend of advanced technology and user-friendly features. Introduced in the early 1990s, this HF transceiver quickly gained a reputation for its exceptional performance, versatility, and reliability, making it a favorite among operators worldwide.

One of the most noteworthy features of the TS-870S is its direct-sampling technology, which allows for superior signal fidelity and processing. This technology enables the transceiver to operate across a range of 160 meters to 10 meters, catering to both casual and serious operators. Its high-performance 16-bit digital signal processing (DSP) facilitates effective noise reduction and filtering capabilities, enhancing the overall clarity during transmission and reception.

In terms of power, the TS-870S boasts an output of 100 watts, providing ample power for various communication needs. The transceiver is equipped with an automatic antenna tuner, which simplifies the task of matching the antenna to the operating frequency, ensuring optimal performance without the hassle of manual adjustments.

Another significant aspect of the Kenwood TS-870S is its user interface, featuring a large, easy-to-read display, and a logically arranged control layout. This makes it accessible for both novice and experienced operators. The built-in memories allow for quick storage and access to favorite frequencies and settings, enhancing operational efficiency.

The Kenwood TS-870S also includes various advanced features such as an optional 2.4 kHz and 6 kHz roofing filter which provides improved performance in crowded band conditions. The receiver's dual VFOs (Variable Frequency Oscillators) enable simultaneous monitoring of two frequencies, which is particularly useful for operators who need to keep track of multiple signals or engage in cross-band communication.

Apart from its technical specifications, the TS-870S is constructed with durability in mind, ensuring that it can withstand the rigors of frequent use. It supports various operating modes, including SSB, CW, AM, and FM, making it a versatile choice for diverse amateur radio activities.

In conclusion, the Kenwood TS-870S combines advanced technology with user-friendly characteristics, offering amateur radio operators an exceptional tool for communication. With its innovative features, robust performance, and flexibility, it continues to be a respected choice among radio enthusiasts, solidifying its legacy in the realm of amateur radio.