STARTFONT 2.1
COMMENT "Id: 10x20.bdf,v 1.68 2000-10-08 09:47:40+01 mgk25 Exp mgk25 $"
COMMENT "Send bug reports to Markus Kuhn "
FONT -Misc-Fixed-Medium-R-Normal--20-200-75-75-C-100-ISO10646-1
SIZE 20 75 75
FONTBOUNDINGBOX 10 20 0 -4
CAP_HEIGHT 13
COPYRIGHT "Public domain font.  Share and enjoy."
CHARS 4246
 ...  

STARTCHAR A
ENCODING 66
SWIDTH 480 0
DWIDTH 10 0
BBX 10 20 0 -4
BITMAP
0000
0000
0000
0C00
1E00
3300
3300
6180
6180
6180
7F80
6180
6180
6180
6180
6180
0000
0000
0000
0000
ENDCHAR
STARTCHAR B
ENCODING 66
SWIDTH 480 0
DWIDTH 10 0
BBX 10 20 0 -4
BITMAP
0000
0000
0000
7C00
6600
6300
6300
6300
6600
7E00
6300
6180
6180
6180
6300
7E00
0000
0000
0000
0000
ENDCHAR
 ...  

STARTCHAR g
ENCODING 103
SWIDTH 480 0
DWIDTH 10 0
BBX 10 20 0 -4
BITMAP
0000
0000
0000
0000
0000
0000
0000
0000
3E80
6380
6300
6300
6300
3E00
6000
3F00
6180
6180
6180
3F00
ENDCHAR

note that we have more than 4000 characters; so truncate to the 97 we really need

A and g with first 3 rows cropped off

here is the raw data, 97*20=1940 lines of text; four bytes plus carriage return = 5 bytes per row of text; 20*5=100 bytes per character, therefore the length of this file is 9700 bytes

using a simple Octave script, bdf2btf.m i now have 10x20.btf (see html font10x20.btf.htm).