Has anyone noticed this?


eberhard keller
 

Or "what happens to Q wen you connect your high Q loop"
to a PL-310,PL-380 etc?
I have been experimenting now for several weeks to come up
with one ferrite rod to cover the entire 150khz to 1700khz,
to connect to these radios with the 1/8" connector mod to
substitute the internal rod.
Along the way I discovered that the radio cares little
about "Q" of the coil,it mostly comes to the mass of
ferrite and the outer limits of the materials permeability.
This became evident to me after I purchased some of
the 5/8"x8" rods sold on $bay,and without making any
measurements placed these in the coils used with amidon
1/2"x7.5" #61 rods,and saw signal indication step-up
of ~3dB over most of the AM band.Coils were wound 175/46
litz on tubing obtained from 19mm knitting needles and
allowed both rod sizes.I eventually made two coils,each
to 350uH 90/44 litz,and tested Q from 530kHz to 1700kHz.
The #61 rod Q was 780 to570,the $bay rod was 400 to 28.
Then I ran a scan of AM stations across the band,
showing a 3dB higher indication with the $bay rod
through most of the band up to 1470kHz and still matching
readings over the rest.
Another comparison made was with two coils of ~200uH,
one #22 mag.wire Q-190 and 90/44 litz Q-750 on #61 rod.
Tuned PL-310 to 810 KGO, 44dB and 46dB.
Any comments?
Eb Keller.

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