FSL coil Q of 1162/46 and 660/46 Litz compared using HP4342A Q meter
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.
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)
I should add that my 140mm ferrite rods are Chinese rods, not Russian rods, and that the results may be different using Russian rods. I don't have enough Russian rods to do the experiment using them. Gary's latest 6" FSL with Russian rods used 19 turns of the 1162/46 Litz where mine used 21 turns.
On 7/5/2020 3:46 PM, STEVE wrote:
Thanks for running these detailed "Q" tests between the 1162/46 and 660/46 Liz wire at various frequencies with the HP4342A Q meter. This kind of detailed test is something which would not be my first choice for using up my hobby time, but I'm happy that somebody did it! :-)
The 1162/46 Litz wire's 'Q" advantage on the low band covers the frequencies which are typically checked first during DXpeditions and band scans, so its substitution for the 660/46 Litz wire in 2014 may have given the impression that it was superior throughout the MW range, which apparently isn't so. But to be honest the recent replacement of the old "N50 365P" variable caps with the newer "N50 384P"variable caps seemed to provide a higher "Q" boost in the newer FSL's than the switch in Litz wire, to the extent that it was the inspiration for the miniature "Frequent Flyer' FSL's which have tracked down long range DX in Hawaii and the Cook Islands.
To make matters even more interesting, Oren Elliott seems to have recently improved his manufacturing process in the later "N50 384P" variable caps, so that the N50 384P caps with a "0219" series number are clearly superior to those with a "0217" series number. I don't know if he has been improving the dielectric, rotor or stator, but these newest variable caps are extremely sharp performers-- to the extent that every FSL antenna heading for the Rockwork Cliff this summer will have one of the latest variable cap upgrades. With Hawaii and all overseas travel temporarily scratched out because of the Pandemic, the Rockwork cliff should be a dream DXing venue for both Tom R. and yours truly, who both broke our records for South Pacific NDB-DX last August. Tom told me that he's still uncovering new South Pacific NDB-DX from that trip, in addition to his record-breaking haul already posted.
I just checked with Mike at https://www.mikeselectronicparts.com/ and he says his current caps are the latest version "0219" so I just ordered one to try.toggle quoted messageShow quoted text
Thanks for this info, Gary.
On 7/5/2020 11:05 PM, Gary DeBock via groups.io wrote: