
                                      Solid Wire Coils

						    Measured Calculated Percent Error
Turns AWG  Form Thickness Diam  Length  Leads  MHz    nH  Q     nH  Q      L      Q
 5     14   air     0      i1     1      .75  25.2   532 474   517 511   -2.8    7.8
 6     14   air     0    i.5625 o.6875   .5   25.2   361 340   358 328   -0.8   -3.5
 6     14   air     0    1.125   1.25   1.125 25.2   700 511   716 550    2.3    7.6
 8     14   air     0   .515625 .71875   .25  25.2   399 288   380 288   -4.8    0.1
 9.06  20 Air Dux  .094    1     1.5     .5   7.96  1155 237  1166 230    0.9   -2.9
                                              25.2  1200 430  1202 401    0.2   -6.7
11.7   18   air     0     .375    .5   .09375 25.2   580 190   570 179   -1.7   -5.8
12     22 phenolic solid  i.25   .875    .5   25.2   280 167   289 179    3.1    7.1
14.07  22 Air Dux  .047  .53125  .875     0   7.96  1230 187  1228 179   -0.2   -4.5
                                              25.2       330       316          -4.2
14     22 phenolic solid  .1875  .375   .125  25.2   273  97   280 105    2.7    8.0
14.2   27 phenolic solid o.15625 .21875 .1875 25.2   300  72   301  73    0.4    1.7
16.75 .125 Air Dux .125  i3.5625  4.5    5.5  2.52 16060 630 15636 638   -2.6    1.2
18.03  14 Air Dux  .125    2.5    2.4     3   2.52 14490 450 14397 410   -0.6   -8.8
                                              7.00       580       630           8.7
19.25  14 steatite .125    o2    2.96     8   7.96 10590 540 10274 569   -3.0    5.4
21     22   air     0    .2125  .5625    .75  25.2   595 137   610 135    2.6   -1.7
24.03  16 Air Dux  .094    2     2.4    1.25  2.52 17600 380 17367 355   -1.3   -6.5
                                              7.00       565       551          -2.4
30.05  12 Air Dux  .1875  i2.5    o5     2.5  2.52 24420 541 24815 525    1.6   -3.0
                                              5.00 26240 640 26599 694    1.4    8.4
30.9   30 phenolic solid i.15625 .34375 .125  7.96  1405  59  1443  54    2.7   -7.9
                                              25.2        96        98           2.1

                  Percent Error
                     L      Q
Average             0.0    0.0
Average magnitude   1.9    5.0
Largest positive    3.1    8.7
Largest negative   -4.8   -8.8

i means inside diameter, o means outside diameter or length. All leads are radial.
Wire is annealed copper except that 16.75 turns is hard-drawn copper.
Air Dux is polystyrene with 40% form contact. Contact for other forms is 100%.
Inductance and Q measured with HP 4342A Q meter. 10 nH residual subtracted.
HP accuracy specs: L 3%, Q < 300 7%, Q 300-600 10%, Q > 600 15%.

Rudy Severns, N6LF, measured the following short coils with an HP 4342A. They used an
octagonal frame of slotted 1" OD PVC with 10% form contact. One coil used slightly
undersize #12 wire. Q measurements contaminated by AM broadcast signals are omitted.

						    Measured Calculated Percent Error
Turns AWG Form Thickness Diag  Length  Leads  kHz     uH  Q     uH   Q     L      Q
 40 .0795  PVC    0.5   i18.62    8     24    250    848 625   837  624  -1.3   -0.2
                                              300    866 670   856  670  -1.1    0.0
                                              350    884 700   881  705  -0.3    0.7
                                              400    920 720   912  729  -0.9    1.2
                                              425    935 725   929  737  -0.6    1.6
                                              450    955 730   949  742  -0.7    1.6
                                              475    968 720   970  745   0.2    3.4
                                              500    993 715   994  745   0.1    4.2
                                              525   1021 698  1020  742  -0.1    6.4
                                              550   1047 680  1049  738   0.2    8.5
 22   19   PVC    0.5   i18.62   4.4    24    396    339 330   340  326   0.2   -1.2
                                              409    344 333   341  331  -0.9   -0.6
                                              428    346 341   343  337  -0.9   -1.0
                                              441    347 348   344  342  -0.8   -1.8
                                              456    348 350   346  346  -0.6   -1.0
                                              490    351 361   350  356  -0.4   -1.3
                                              534    355 375   355  368   0.1   -1.9
                                              592    362 390   364  380   0.5   -2.6
                                              673    373 401   378  392   1.3   -2.3
                                              727    384 401   389  396   1.3   -1.2
                                              798    398 390   406  398   2.1    2.1
                                              852    411       422        2.6
                                              898    419       437        4.2
                                              942    439       453        3.2
                                             1038    470       496        5.5
 18   19   PVC    0.5   i18.62   3.6    24    474    250 318   248  317  -0.7   -0.3
                                              501    252 325   250  325  -0.9   -0.1
                                              534    254 332   252  333  -0.8    0.4
                                              574    256 342   255  343  -0.4    0.2
                                              626    259 356   259  354   0.0   -0.7
                                              694    263 369   265  365   0.9   -1.1
                                              736    267 375   270  371   1.0   -1.2
                                              788    272 375   276  376   1.4    0.2
                                              851    280       284        1.4
                                              937    291       297        2.2
 5    19   PVC    0.5   i18.62    1     24   1317   31.1 216  30.2  220  -2.8    1.9
                                             1423   31.3 224  30.5  227  -2.6    1.6
                                             1518   31.4 230  30.7  234  -2.1    1.6
                                             1635   31.6 239  31.1  241  -1.6    0.7
                                             1780   32.0 249  31.6  248  -1.4   -0.3
                                             1976   32.4 258  32.3  257  -0.4   -0.5
                                             2050   32.8 260  32.6  260  -0.7   -0.2
                                             2096   32.9 260  32.8  261  -0.4    0.4
                                             2180   33.3 255  33.2  264  -0.4    3.4
                                             2244   33.5      33.5       -0.1
                                             2322   33.6      33.9        0.8
                                             2391   34.1      34.2        0.4
                                             2691   35.0      36.1        3.0
                                             3032   36.7      38.7        5.5
                                             3522   40.8      44.1        8.2
                                             3839   43.0      49.1       14.3
                                             4213   47.6      57.6       21.1

These short coils used a square frame of slotted 1" OD PVC with 6% form contact.

						    Measured Calculated Percent Error
Turns AWG Form Thickness Diag  Length  Leads  kHz     uH  Q     uH   Q     L      Q
 40   19   PVC    0.5   i18.62    8     24    276    707 335   695  331  -1.7   -1.2
                                              300    714 352   702  344  -1.7   -2.4
                                              350    725 381   717  367  -1.1   -3.8
                                              400    740 407   736  385  -0.6   -5.4
                                              450    758 421   758  399   0.0   -5.3
                                              500    785 439   785  408   0.0   -7.0
                                              550    813 453   817  413   0.5   -8.8
                                              600    838 450   855  414   2.0   -8.1
                                              650    869 450   901  410   3.6   -8.9
 20   19   PVC    0.5   i18.62    4     24    465.3  249 310   245  306  -1.8   -1.2
                                              485.3  250 315   246  312  -1.7   -0.9
                                              502.5  251 320   247  317  -1.7   -1.0
                                              535.0  253 330   249  326  -1.7   -1.4
                                              576.7  254 341   251  336  -1.0   -1.6
                                              627.5  257 356   255  346  -0.7   -2.7
                                              696.1  261 370   261  358   0.0   -3.2
                                              747.9  266 380   266  366   0.0   -3.8
                                              790.9  270 389   271  370   0.3   -4.8
                                              856.0  277 381   279  376   0.6   -1.4
                                              940.7  286       291        1.6
                                              1234   333       354        6.4
                                              1555   419 291   513  278  22.5   -4.4

This coil used slightly undersize #10 wire on a grooved steatite form.

						    Measured Calculated Percent Error
Turns AWG Form Thickness Diam  Length  Leads   kHz    uH  Q     uH   Q     L      Q
 25  .101 stea   0.25   o4.139  4.13    12    1132  42.1 440  42.9  443   1.8    0.7
                                              1223  42.3 449  43.0  459   1.7    2.3
                                              1306  42.4 468  43.2  474   1.8    1.2
                                              1407  42.6 484  43.3  490   1.7    1.2
                                              1568  42.9 509  43.6  514   1.7    0.9
                                              1716  43.0 528  44.0  533   2.3    1.0
                                              1854  43.3 540  44.3  550   2.3    1.9
                                              1968  43.6 550  44.6  563   2.3    2.4
                                              2185  44.2 558  45.3  585   2.4    4.8
                                              2377  44.8 560  45.9  601   2.5    7.4
                                              2788  46.5 568  47.6  628   2.3   10.6
                                              3213  49.1 550  49.7  643   1.2   17.0
                                              4236  56.5 415  57.5  632   1.7   52.3

Steve Ratzlaff, AA7U, measured the following very short, close-wound coils on polypropylene
and styrofoam forms. He used an IET Labs DE5000 at 100 kHz and an HP 4342A above.          

						    Measured Calculated Percent Error
Turns AWG Form Thickness Diam  Length  Leads  kHz    uH   Q    uH    Q     L      Q
 20   28   pp    .0625   3.68   0.325    7    100   78.2      77.5       -0.9
                                              821   80.0 118  78.4  130  -2.0   10.2
                                              888   80.3 121  78.6  133  -2.1    9.6
                                              948   80.5 124  78.8  135  -2.2    8.6
                                             1021   81.0 126  79.0  137  -2.5    8.5
                                             1115   81.5 130  79.3  139  -2.7    6.8
                                             1242   82.1 134  79.7  141  -2.9    5.3
                                             1425   83.2 139  80.5  144  -3.3    3.3
                                             1723   85.3 146  81.9  146  -3.9    0.2
                                             2340   92.5 149  86.3  156  -6.8    4.4
                                             3143  102.6 145  95.1  167  -7.3   15.0
 12   22  styr   solid     i8    0.41    8    100   71.1      70.7       -0.6
                                              861   72.7 172  72.1  167  -0.9   -3.1
                                              929   73.4 176  72.4  173  -1.4   -1.6
                                              988   74.1 181  72.6  179  -2.0   -1.3
                                             1063   74.7 186  73.0  185  -2.3   -0.5
                                             1160   75.3 192  73.5  193  -2.4    0.5
                                             1293   75.8 200  74.2  203  -2.0    1.3
                                             1479   77.2 206  75.5  214  -2.2    4.1
                                             1780   80.0 219  78.1  229  -2.4    4.8
                                             2375   89.8 224  85.4  245  -4.9    9.6
                                             3120  104.1 216   101  241  -2.9   11.4
 12   18  styr   solid     i8     0.7    9    100   65.2      61.1       -6.3
                                              898   66.8 195  62.2  250  -6.8   28.1
                                              968   67.6 200  62.5  259  -7.6   29.5
                                             1032   67.9 204  62.7  267  -7.7   30.9
                                             1110   68.5 211  63.0  276  -8.0   30.9
                                             1214   68.7 218  63.5  288  -7.6   32.0
                                             1346   69.9 226  64.1  301  -8.3   33.1
                                             1541   71.1 236  65.2  318  -8.3   34.6
                                             1856   73.5 256  67.4  339  -8.3   32.5
                                             2462   83.6 251  73.5  361 -12.0   43.9
                                             3230   97.1 241  86.8  354 -10.6   46.8


				    Litz Coils

AA7U measured the following Litz coils wound on a polystyrene form. 660/.04 measured twice.

 40/.04: 1 bundle  of 40 strands    Chinese wire with 0.04 mm strands sold as #46
100/.04: 5 bundles of 20 strands
175/.04: 5 bundles of 35 strands
330/.04: 6 bundles of 55 strands    Too many bundles, too many strands per bundle
660/.04: 5 bundles of 3 sub-bundles of 26 strands and 2 sub-bundles of 27 strands

SBR is the ratio of strands/bundle to COIL's conservative limit.

						    Measured Calculated Percent Error
Turns Wire Form Thickness Diam  Length  Leads  kHz   uH   Q     uH   Q     L      Q     SBR
40 100/.04 psty    .13   i4.48   1.04    12    100  271        272        0.3
                                               550  282  398   279  387  -1.1   -2.8    1.0
                                               700  290  486   284  477  -2.2   -1.8    1.3
                                              1000  317  615   297  625  -6.2    1.7    1.8
                                              1400  349  675   327  742  -6.3    9.9    2.6
50 175/.04 psty    .13   i4.48   1.68    13    100  341        344        0.9
                                               550  359  653   355  660  -1.1    1.1    1.8
                                               700  372  767   363  794  -2.5    3.6    2.2
                                              1000  422  900   385  978  -8.8    8.7    3.2
                                              1400  488  880   435 1043 -10.8   18.5    4.5
45 330/.04 psty    .13   i4.48   2.03    12    100  253        254        0.3
                                               550  263  760   260  934  -1.2   22.8    2.8
                                               700  272  880   264 1090  -3.1   23.9    3.5
                                              1000  295 1000   275 1260  -6.8   26.0    5.0
                                              1400  331  965   299 1252  -9.5   29.7    7.1
45 660/.04 psty    .13   i4.48   2.9     12    100  210        209       -0.4
                                               550  216 1376   213 1334  -1.3   -3.1    1.3
                                               700  222 1493   216 1463  -2.8   -2.0    1.7
                                              1000  239 1486   223 1499  -6.5    0.9    2.4
                                              1400  264 1258   239 1321  -9.4    5.0    3.4
45 660/.04 psty    .13   i4.48   2.9     12    100  205        209        2.0
                                               510  210 1320   213 1283   1.2   -2.8    1.2
                                               700  217 1500   216 1463  -0.5   -2.5    1.7
                                              1000  232 1525   223 1499  -3.7   -1.7    2.4
                                              1400  258 1318   239 1321  -7.3    0.2    3.4
                                              1700  283 1100   257 1136  -9.3    3.2    4.1
                                              2000  264  847   281  948   6.5   11.9    4.8

These very short Litz coils used polypropylene and styrofoam forms.

						    Measured Calculated Percent Error
Turns Wire Form Thickness Diam  Length  Leads  kHz   uH   Q     uH   Q     L      Q     SBR
16  40/.04  pp   .0625    3.72   0.32     7    100  49.2      50.7        3.1
                                              1032  50.6 160  51.4  166   1.6    4.0    3.8
                                              1115  50.9 170  51.5  179   1.2    5.3    4.1
                                              1283  51.3 193  51.8  204   0.9    5.7    4.7
                                              1563  51.8 224  52.3  244   1.0    8.8    5.7
                                              1795  52.4 244  52.8  275   0.9   12.6    6.6
                                              2162  54.2 270  53.9  319  -0.6   18.3    7.9
9  175/.04 styr  solid     i8     0.3     7    100  42.3      42.9        1.3
                                              1108  43.9 435  43.8  511  -0.1   17.6    3.6
                                              1195  44.3 452  44.0  545  -0.7   20.5    3.8
                                              1280  44.2 468  44.2  576   0.0   23.0    4.1
                                              1375  44.7 482  44.4  609  -0.7   26.3    4.4
                                              1502  44.9 500  44.7  650  -0.4   30.0    4.8
                                              1675  45.1 510  45.2  700   0.2   37.3    5.4

N6LF measured the following Litz coils. The windings had 10% contact with an octagonal frame
of 0.375" fiberglass rods.

1/66/.08: 1 bundle  of 66 strands    Too many strands per bundle
3/22/.08: 3 bundles of 22 strands    Q error high/inverted - micrometer suggests 3/22/.07
125/44:   5 bundles of 25 strands    MWS wire

						    Measured Calculated Percent Error
Turns Wire Form Thickness Diag  Length  Leads  kHz   uH   Q     uH   Q     L      Q     SBR
91 1/66/.08 fib   .375   i5.27    3.7    36    475 1011  610   969  724  -4.2   18.6   11.5
91 3/22/.08 fib   .375   i5.27    3.7    36    250  921  420   905  516  -1.7   22.9    2.0
                                               475 1003  640   969  724  -3.4   13.1    3.8
91 3/22/.07 fib   .375   i5.27    3.7    36    250  921  420   905  425  -1.8    1.2    1.5
                                               475 1003  640   967  668  -3.5    4.4    2.9
65  125/44  fib   .375   i5.27    2.2    36    300  621  455   618  474  -0.4    4.3    1.1
                                               350  632  520   624  540  -1.2    3.9    1.3
                                               400  642  572   631  601  -1.7    5.0    1.4
                                               450  649  620   639  655  -1.6    5.6    1.6
                                               475  655  650   643  679  -1.8    4.5    1.7
                                               500  662  665   648  702  -2.1    5.6    1.8
                                               550  673  692   658  742  -2.2    7.3    2.0
                                               600  682  710   670  776  -1.8    9.2    2.2
                                               650  698  718   683  802  -2.1   11.6    2.3
                                               700  714  705   698  820  -2.3   16.3    2.5