Soundblaster 16

 

 

 

 

 

 

 

 

        Toshiba 2545 Laptop (Yamaha)

 

 

 

 

 

 

 

 

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Center frequency is 1000 Hz, frequency span is 500 Hz or 50 Hz/div  and vertical scale is 10 db/div.  Resolution BW is 10 Hz and Video BW is 1 Hz.
As can be observed, there is no significant difference between the two sound card outputs and the spectrum is very clean to the noise level which is ~60 db below the peak signal.
KENWOOD TS-570S
The Kenwood TS-570S data was taken with the radio input/output via the 13 pin DIN connector at the rear of the transceiver.  AF input level for digital operation (function 33) is set to 0.  PTT is via the 13 pin DIN connector which disables the microphone (removed in any case).  Power output level is set to 100 watts and the idle power level is adjusted via the sound card volume control.
The following figures display power output levels from 10 -50 watts in increments of 10 watts.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  TS-570S @ 10 watts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

               TS-570S @ 30 watts

 

 

 

 

 

 

 

 

                 TS-570S @ 40 watts

 

 

 

 

 

 

 

 

 

 

 

 

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TS-570S @ 50 watts

 

 

 

 

 

 

 

 

 

 

 

All measurements made at 14.071 MHz with resolution BW @ 10 Hz and video BW @ 30 Hz.  Reference level constant.
Yaesu FT-1000MP
The FT-1000MP data was taken with the radio input/output via the phone patch and PTT  connector at the rear of the transceiver.  This was done since packet operation is on LSB only and consistency was desired between transceivers.  Power output level is set to 100 watts and the idle power level is adjusted via  a combination of the sound card volume control and transceiver microphone gain.  Transceiver mike gain level was set near normal (about 9 o'clock) and fine adjustments made with sound card volume control.  The results are shown in the following figures at power levels of 10 through 50 watts respectively

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                 FT-1000MP @ 10 watts

 

 

 

 

 

 

 

 

                 FT-1000MP @ 20 watts

 

 

 

 

 

 

 

 

 

 

 

 

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                 FT-1000MP @ 30 watts

 

 

 

 

 

 

 

 

                 FT-1000MP @ 40 watts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                 FT-1000MP @ 50 watts

 

 

 

 

 

 

 

 

 

 

 

All measurements made at 14.070 MHz with resolution BW @ 10 Hz and video BW @ 30 Hz.  Reference level constant.  Subsequent to these measurements I discovered that the DVS-2 input on the rear of the FT-1000MP could be used  for this mode.  No changes in the performance were observed when using this interface.

In addition, on this transceiver, measurements were made at 1.85 MHz and 28.080 MHz to ascertain if any differences in performance were related to frequency of operation.  These measurements in shown below made at 40 watts output with spectrum analyzer settings as shown in the previous figures.

 

 

 

 

 

 

 

 

 

 

 

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         FT-1000MP @ 40 watts and 1.85 MHz

 

 

 

 

 

 

 

 

FT-1000MP @ 40 watts and 28.08 MHz

 

 

 

 

 

 

 

 

 

 

 

KWM-2A/30L1

While the frequency stability of the Collins KWM-2A is probably only marginally adequate  for PSK-31, and that only after good warm up, I was still interested in comparing that transceiver's performance to the  more modern equipment.  There are of course significant design and technology differences between the Collins and the two previously measured transmitters.  Among these are;

  1. Tube versus solid state
  2. Synthesized versus non-synthesized.

The KWM-2A results are shown below for powers of 10 to 60 watts .  Setup was as previous, 14.070 MHz and the same analyzer adjustments.  Input for the sound card audio is via the phone patch input with the microphone disconnected and power adjustment made via the microphone control.  Transceiver tuning was as proscribed in the instruction manual and maximum power output under the key down operate setting was  105 watts.   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

KWM-2A @ 20 watts

 

 

 

 

 

 

 

 

 

 

 

 

 

KWM-2A @ 10 watts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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KWM-2A @ 30 watts

 

 

 

 

 

 

 

 

KWM-2A @ 40 watts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

KWM-2A @ 50 watts

 

 

 

 

 

 

 

 

KWM-2A @ 60 watts

 

 

 

 

 

 

 

 

 

 

 

At 60 watts,  the level of input was providing the maximum level of ALC recommended for SSB operation.  While clearly being over driven, it is interesting to see the performance is not much worse than some of the other measurements at much lower levels (~-21db) and remarkably similar in appearance.
Since the KWM-2A performance better than expected, I decided to look at the combination KWM-2A and 30L1 linear amplifier.  The 30L1 output level was adjusted to 200 watts output which corresponds to a level of 30 watts drive from the KWM-2A.  The following spectrum photograph shows the results.  Again the frequency is 14.070 MHz  and analyzer settings are as in previous measurements.

 

 

 

 

 

 

 

 

 

 

 

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SUMMARY
To show some more definitive numbers I have included the table below.   The table shows a measured comparison between the worst case 1st sideband of each transceiver output at 30 watts.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appendix

After several comments were received and in light of the ongoing discussion on the PSK31 reflector I thought it might be informative to add the following spectrum analyzer and oscilloscope pictures. 
The spectrum picture shows a single tone spectrum compared to a BPSK spectrum.  These are accurately portrayed in that the power levels are the same for the single tone and each of the shifted BPSK carriers and these represent average powers.  The oscilloscope picture on the other hand shows the reason for backing down the average power in that the peak envelope voltage is 6db higher than the peak voltage of the single tone carrier.  The peak envelope power is therefore 3db higher - thus the recommendation to adjust the BPSK idle condition, which is shown in these pictures, for approximately ½ or -3db down from the single tone carrier or cw signal.  Now, the only question remains is where does your rig begin distorting the signal.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BPSK vs Carrier

 

 

 

 

 

 

 

 

BPSK vs Carrier Spectrum