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•
Next, to get into the alignment mode, turn the radio off, now press the [A], [B],
and [C] keys, and hold them in while you turn the radio on. Now press and hold
the [FUNC] key, as you normally would to get into the Menu. You'll find that the
Menu is now different.
•
Rotate the selector knob until you find "F-07 [S FULL SCALE]" on the display.
Make a note of the current setting of this item, so you can go back to it if you
want to. Now adjust this item just like any other Menu item, by rotating the main
dial, until you get a full scale reading on the S-meter.
•
There also is an adjustment of the 144 MHz RF Gain (F-01) and the 144 MHz IF
Gain (F-05). Perhaps a little adjustment to the RF Gain would help with the weak
repeaters. Whatever you do, make a note of the original settings of these items.
Adding too much front end gain can degrade the intermodulation performance of
the receiver section. Also, if you change the RF or IF Gain, the S-meter indication
will change, too.
•
Press the [FUNC] key to exit the alignment mode.
If you have the equipment for it, you can more accurately adjust the s-meter by injecting
a 14.200 MHz signal in USB mode into the antenna at +95dbmicroVolt and adjust F07 to
read S9+60dB. You could also adjust it for an S9 reading on 40 Meters using 50
microvolts rms for S9, then "re-calibrate" the S meter mentally by remembering that
above S5 the "S reading" is one S unit higher than actual, and also that S9+20dB is
actually S9+15dB, S9+40 is S9+25 and S9+60 is S9+35.
There is only a single adjustment for the S meter which amounts to a DC offset. (It's NOT
a scalar!) All you can do is shove the entire curve one way or the other. Most simple RSL
indication circuits at least use a DC offset along with a DC gain setting. The latter allows
you to set the steepness of the indicated RSL (receive signal level) function. The whole
business is about proper interpretation of either a detector output or the AGC voltage. The
FT-100D uses the AGC voltage to generate the indicated RSL. But they only included
one control (DC offset) to you're really limited in terms of setting the accuracy of it.
Probably the best thing to do is to calibrate it on your favorite band for the standard
50 microvolts RMS (single sinusoid) for S9 and perhaps characterize your "indicated
RSL versus actual RSL" so at least you know how to translate what the meter is
indicating.
FT100D CW signal. Assume first segment is S2 based on relationship to segment which
corresponds to S9.
7.2 MHz
setting 205
With S9 set for -73 dBm
Segments Display
readout
Equivalent
standard
level (dBm)
Actual level
in dbm
Actual level
in "S" units
Display
error
1
S2
-115
-102
S4
2 S units low
2
S3
-109
-101
S4
1 S unit low
3
S4
-103
-99
S5
1 S unit low
4 S5
-97 -98 S5 0
5
S6
-91
-96
S5
1 S unit high
Summary of Contents for FT-100 Micro Mobile
Page 1: ...Yaesu FT 100 undocumented Compiled by PA3GMP Printed 4 April 2004...
Page 10: ...9 ATAS 100 Disassembly...
Page 11: ...10...
Page 12: ...11...
Page 13: ...12...
Page 20: ...19 After the factory mod...
Page 22: ...21 Prior to modification...
Page 23: ...22 Prior to modification...
Page 24: ...23 After modification...
Page 37: ...36...
Page 46: ...45 FT100 menu settings Entry Set to Description Remarks...
Page 47: ...46 FT100 menu settings Entry Set to Description Remarks...
Page 48: ...47 FT100 menu settings Entry Set to Description Remarks...
Page 49: ...48 FT100 menu settings Entry Set to Description Remarks...
Page 50: ...49 FT100 menu settings Entry Set to Description Remarks...
Page 51: ...50 Frequency list Freq Mode Memory Description...
Page 52: ...51 Frequency list Freq Mode Memory Description...
Page 53: ...52 Frequency list Freq Mode Memory Description...
Page 54: ...53 Frequency list Freq Mode Memory Description...
Page 55: ...54 Frequency list Freq Mode Memory Description...