Passband Analysis on my TS-850
Thanks to Gary E. Bold, ZL1AN, for his help and the original idea to do this!
These are passband plots of the response of my TS-850 to noise tuned in
on an inactive frequency. I connected the output of my headphone jack through a
matching transformer to the soundcard of my computer. I recorded the audio with various
filter and control settings, then did a Fourier Transform on the sound file.
Don't pay attention to the absolute dB scale shown. The measurements are relative to oneanother
only. You cannot conclude insertion losses, etcetera from this data. It's kind of for entertainment
purposes only :)
If you would like to see how your rig compares. Then send me a recording! I can't promise a rapid
turn around time, but I will get to it. Here is what you do:
- Download the shareware sound recording program "GoldWave" from http://www.goldwave.com
- Run GoldWave on your computing platform
- Open a "New" file set for 10 seconds of 16 bit mono recording with either 8K or 16K sample rate
(make sure you tell me which!)
- Tune to an empty frequency and record the noise
Save the recording in MATLAB (.MAT) format
Zip up the recordings and send them to me with a description of each file
Bear in mind that this is an overall measurement. The effects of a speaker and microphone will be included
if you do not record directly to the sound card. This is okay, but it will bias the plot to some extent.
It is likely that the low frequency behavior shown in my plots is due to the action of the matching transformer
I have inline between the rig and the computer.
- Set the recording level correctly
- Make sure the recordig level stays 'in the green'
- Alternatively in the frequency display keep the baseline at a minimum and the passband peak at a
I have a full compliment of four
filters installed. The "first" IF (8.83MHz)
has a choice of no filter, 6KHz stock, 2.7KHz stock, 2.1KHz InRad, or 400Hz InRad filter.
The "second" IF (455KHz) has a choice of 12KHz stock, 6KHz stock, 2.1KHz InRad, or 400Hz InRad filter.
A plot comparing the overall response of just the CW filters. I include using the slope tune controls to
modify the width to about 250Hz.
A plot comparing the overall response of slope tuning to modify the width to about 250Hz with
both the cascaded 400Hz filters and the 2.1KHz filters. I include the unmodified 400Hz pair for
A plot comparing the overall response of just the SSB filters. I include a 'no filter' comparison with
just the stock 6KHz filters cascaded.
An expanded version of the previous plot.
Use this plot to compare the filter skirts.
A plot showing the effectivness of the notch filter. The depth is pretty good, but the slope in not.
TS-850 versus Ten-Tec Omni-D
It's not a fair fight, but I am comparing anyway!
Comparisons between my current TS-850 and the Ten-Tec Omni-D I previously owned. The TS-850 is set for
500Hz pitch. The Omni-D is centered at 750Hz.
Comparisons between my current TS-850 and my previously owned Ten-Tec Omni-D.
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