My personal TS-870S notes - some fact / some opinion - but always accurate (hihi):

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Maximum Transmit Audio Response Test

Notes to table below:

  • Careful attention was made to make sure no ALC was ever engaged during testing at any frequency.
  • Transmit DSP Filter Bandwidth was set to maximum of 3.0 Khz (MENU 29 "TX WIDTH").
  • No internal EQ was used. Speech processor - OFF
  • Digital readout Kenwood signal generator used for accuracy - directly fed into the front panel mike input.
Roll Off
(vs. 1 Khz.
Reference 0 db)
DSP "TX SHIFT"
MENU 30 - Set to "0"
DSP "TX SHIFT"
MENU 30 - Set to "100"
Low Frequency
High Frequency
Low Frequency
High Frequency
-3 db
183 Hz.
3.04 Khz.
187 Hz.
3.15 Khz.
-6 db
38 Hz.
3.12 Khz.
113 Hz.
3.25 Khz.
-9 db
26 Hz.
3.19 Khz.
91 Hz.
3.34 Khz.
-12 db
20 Hz.
3.25 Khz.
78 Hz.
3.40 Khz.

If you hear me on my TS-870S I am usually running MENU 30 "TX SHIFT" at 100 Hz. (low end that 90% of the folks can hear & nice high end response).

I usually run a professional microphone & external audio processing (dbx "ProVocal" strip) & DI box into the microphone input with my TS-870S for best results.


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SSB Receive DSP Filters (120 possible filter combinations)
Control Knob
Description
Frequency Selections
LO/WIDTH
Sets the high-pass DSP filter cutoff
0, 50, 100, 200, 300, 400, 500, 600, 800, 1000 Hz.
HI/SHIFT
Sets the low-pass DSP filter cutoff
1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.5, 2.8, 3.0, 3.4, 4.6, 6.0 Khz.

AM Receive DSP Filters (24 possible filter combinations)
Control Knob
Description
Frequency Selections
LO/WIDTH
Sets the high-pass DSP filter cutoff
0, 100, 200, 500 Hz.
HI/SHIFT
Sets the low-pass DSP filter cutoff
2.5, 3.0, 4.0, 5.0, 6.0, 7.0 Khz.

CW Receive DSP Filters (6 possible filter combinations)
Control Knob
Description
Frequency Selections
LO/WIDTH
Sets the bandwidth of the DSP filter
50, 100, 200, 400, 600, 1000 Hz.
HI/SHIFT
Sets the CW shift
400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000 Hz.

FM Receive DSP Filters (6 possible filter combinations)

Control Knob

Description
Frequency Selections
LO/WIDTH
Sets the bandwidth of the DSP filter
5, 6, 8, 10, 12, 14 Khz.
HI/SHIFT
No Function
-

FSK Receive DSP Filters (4 possible filter combinations)
Control Knob
Description
Frequency Selections
LO/WIDTH
Sets the bandwidth of the DSP filter
250, 500, 1000, 1500 Hz.
HI/SHIFT
No Function
-


Pros:
  • One of THE best sounding, smooth - truly audiophile transceivers made. Probably now matched by the Yaesu FT-2000 and beat only by the Kenwood TS-950SD/SDX models and the SDR radios (Flex Radio).
  • Very nicely built.
  • Fantastic DSP filters - ALL receive filters can be created "on the fly" with front panel controls (see above). "Brick wall" DSP filtering.
  • Typical Kenwood - silky smooth VFO knob tuning (MENU choice of 5 or 10 Khz. per revolution). 1 Khz. per revolution by pushing the "FINE" button
  • Big control knobs and only one layer of menus
  • Utilizes two 24-bit 20 MIPS DSP chips - IF DSP
  • Includes the K-1 Logic Keyer (built in) - this is also a fantastic CW rig
  • Incredible value on the used market now (2010) - selling for almost half what they cost new (more or less depending on age and condition)
  • Choice of continuously variable or automatic AGC release time.
  • Rig never gets warm
  • Separate - front panel - fast tune dial (menu choice of 1, 5 or 10 KHz. steps)
  • Accurately reads out and tunes in 10 Hz. steps - by pushing the "FINE" button tunes in 1 Hz. steps (1 Khz. per VFO dial revolution). The VFO dial only reads to 10 Hz. BUT 1 Hz. steps can be read on external computer control programs (like Ham Radio Deluxe).
  • Antenna tuner is quiet and fast
  • DB-9 connector on back panel for easy computer control
  • Works very well with HRD (Ham Radio Deluxe) software - fast communication with P.C. at a baud rate of 57,600
  • Very quiet receive - fatigue free listening
  • Unbeatable VOX - to avoid ANY lost first syllable. Transmit audio (when VOX is enabled) is actually digitally delayed (very short time) before it is transmitted (this can be witnessed by using headphones & turning on the monitor function).
  • Segment LED meter is curved - resembles action of an analog meter with added benefits
  • Feature rich rig - just download the manual from Kenwood and be amazed ! Hard to believe - this rig was designed over 15 years ago.

Cons:

  • No longer in production
  • Requires the TCXO option (SO-2) to take full advantage of this great rig (should have been standard). Will hold to commercial levels of +/- 0.5 PPM with the SO-2 installed
  • No direct access to individual bands - "Up - Down" buttons are used to toggle through each band
  • AM transmit mode is a bit tricky - will not fully modulate at 25 watts output (expect reports of low audio). ALC starts to kick in early and limits the rigs ability to fully modulate. Easy fix is to run an amplifier behind the TS-870 and run the rig at 10-15 watts output for best results. This will keep the audio peaks well below the threshold of the ALC. With a pair of 3-500Zs amplifier this should produce 100-150 watts output of excellent sounding AM. Audio gain will still need to be high (ie...MIC gain at 2-3 o'clock).
  • Maximum CW bandwidth is only 1 Khz.

 

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