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565cfadjust [2007/05/21 00:43] 127.0.0.1 external edit |
565cfadjust [2013/04/06 01:03] n2fq |
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| 73, Bill W4ZV | 73, Bill W4ZV | ||
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| + | **Alternate method for adjusting the 250Hz and 500Hz CF Using Spectrogram** | ||
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| + | -A PC with sound card is needed | ||
| + | -A copy of Spectrogram.exe and a cable from rig audio out to PC mic input | ||
| + | -The registration for the program is optional since the 10 minutes it runs is ample time to do the adjustment | ||
| + | -A copy of the pdf titled "Using Spectrogram To Measure Filter Response" by | ||
| + | John Grebenkemper, KI6WX that will help with the initial setting of the program. | ||
| + | -Use a noise generator at the antenna input or use an empty spot on a band and use the background noise. | ||
| + | -Connect the rig audio out to the computer's sound card. | ||
| + | -Start Spectrogram and use the above document and set the initial settings. This is trivial and will take a few minutes. | ||
| + | -Place the rig BW just a tad less than 500Hz to engage the 500 filter. | ||
| + | -Under the menu item on the rig select 500Hz CF Adj. | ||
| + | -In Spectrogram, place the cursor (usually a cross hair) in the center of the bandwidth shown. | ||
| + | -Or you can calculate it by subtracting the lower skirt edge from the upper skirt edge, dividing that result by 2, and adding this to the lower edge reading. | ||
| + | -Back on the rig, use the Multi knob to center it. | ||
| + | -Repeat for the 250Hz by setting the rig's BW to a tad less than 250Hz. | ||
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| + | Here is a short Youtube video depicting what I'm trying to describe above http://youtu.be/7Pcp4pU2VwM | ||
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| + | 73, Fernando N2FQ/6 | ||
