This experiment compares a ferrite sleeve coil of 1162/46 Litz
with a ferrite sleeve coil of 660/46, both 21 turns with final
coil diameter about 6 3/8", using 140 mm ferrite rods in the
ferrite sleeve. The same ferrite sleeve was used for both coils,
with the coils centered on the sleeve for peak inductance. The
1162/46 coil measured 236.5 uH; the 660/46 coil measured 253 uH
for the same 21 turns for each. (The fatter Litz will have a
little less inductance compared to the thinner Litz for the same
number of turns due to being a wider coil.)
Each ferrite sleeve coil was suspended 7" above the Q meter deck,
oriented horizontally; each coil had about 12" of pigtail length.
The HP4342A Q meter capacitor (very high Q) was used to resonate
each coil. Solid copper lugs were used on the ends of each coil to
connect the coil to the Q meter. Coil Q should directly relate to
signal level coupled to the receiver with higher Q giving higher
signal level. Since the Q meter's variable capacitor was used,
which has much higher Q than any external variable capacitor I'm
aware of, this removes the external capacitor Q effects from the
experimental results, only comparing the two Litz types.
73,
Steve AA7U
1162/46
660/46
1700 kHz 305Q 310Q
1600 kHz 345Q 350Q
1500 kHz 385Q 395Q
1400 kHz 440Q 445Q
1300 kHz 500Q 500Q
1200 kHz 565Q 570Q
1100 kHz 643Q 645Q Q's are
equal at this frequency
1000 kHz 740Q 730Q Fatter Litz
begins to have better Q
900 kHz 840Q 835Q
800 kHz 955Q 930Q
700 kHz 1116Q 1084Q
600 kHz 1246Q 1144Q
550 kHz 1301Q 1173Q
520 kHz 1332Q 1186Q
1162/46 Litz--385 pF, 516 kHz, 1333Q
(max capacitance of variable cap Gary uses)
510 kHz 1188Q
660/46 Litz--385 pF, 502 kHz, 1189Q (max
capacitance of variable cap Gary uses)