Heathkit SB-
During the process of re-
With respect to the adjustable inductors, ‘Core in’ is the maximum inductance position and ‘Core out’ is with the outer end of the core level with the top of the former.
All measurements were taken on a Marconi TF-
|
|
Core Out |
Core In |
Inductance (uH) |
Winding details |
|
||||
Heath Part No |
Freq MHz |
Cap pF |
Q |
Cap pF |
Q |
Min |
Max |
Turns |
Length (inches) |
Comment |
40_529 |
28 |
91 |
110 |
46 |
96 |
0.36 |
0.7 |
7 |
0.33 |
|
40_551 |
10 |
295 |
82 |
138 |
113 |
0.86 |
1.84 |
13 |
0.4 |
|
40_550 |
10 |
119 |
115 |
245 |
94 |
1.03 |
2.13 |
15 |
0.45 |
|
40_551 |
14 |
148 |
92 |
70 |
110 |
0.87 |
1.85 |
13 |
0.4 |
|
40_552 |
14 |
268 |
97 |
148 |
111 |
0.48 |
0.87 |
9 |
0.41 |
|
40_601 |
3.5 |
>500pF |
90 |
280 |
90 |
N/A |
7.38 |
26 |
0.45 |
40_764 is similar |
40_765 |
7 |
213 |
106 |
89 |
112 |
2.43 |
5.81 |
21 |
0.38 |
|
40_767 |
21 |
188 |
93 |
99 |
112 |
0.31 |
0.58 |
6 |
0.29 |
|
40_768 |
28 |
125 |
108 |
60 |
120 |
0.26 |
0.54 |
5 |
0.25 |
|
40_811 |
14 |
131 |
108 |
57 |
112 |
0.99 |
2.27 |
13 |
0.26 |
|
40_832 |
18 |
187 |
89 |
88 |
91 |
0.42 |
0.89 |
8 |
0.25 |
|
The underscore in the part number should be read as a hyphen i.e. 40_529 = 40-
The capacitance columns are those values required to resonate each inductor at the specified frequency for the respective core positions. Readers can calculate resonant frequencies with other capacity values as required.
All of these coils are wound on formers made of a relatively thin material with an outer diameter of 9/32 (0.28) inch, an adjustable dust iron core and a chassis mounting clip. Considerable care is required in moving the cores as they break very easily -
SB- |
Measurements taken without shorting out the unused sections of the inductor |
|||
Band MHz |
Resonant freq MHz |
With test capacitor pF |
Measured Q |
Calculated inductance uH |
3.5 |
21.8 |
200 |
262 |
9.99 |
7 |
17.09 |
150 |
220 |
4.04 |
14 |
9.82 |
150 |
185 |
1.75 |
21 |
6.46 |
100 |
148 |
0.87 |
28 |
3.56 |
100 |
140 |
0.53 |
Shorting out the unused sections of the inductor as was done in the SB-