[HBR] Coil 'Q'

[Diane Swynar]

Hi Kees...

I always use clear nail polish to seal the turns of my coils---in fact, I
apply no less than two coats before I'm satisfied that the darn things
won't unravel on me.

The loss in Q is, to my mind anyway, a small price to pay for consistency
in inductance value. I never would have used it at all, really, were it not
for the fact that the stuff smells just like the old "G-C Q-DOPE" of bygone
days...

~73~ Eddy VE3CUI - VE3XZ






>>From coils shields to the coils themselves........
>
> Tried a few different coil forms and got the attached data.
>
> The 1-1/4" amber plastic pill bottle looks good, is cheap, is
> available, but it's not sturdy and needs a connector attached.
> The PVC looks surprisingly good, is cheap, is readily available,
> is sturdy and needs a connector attached.
>
> I wouldn't use paper/cardboard as a coil form and definitely
> don't use fingernail polish to hold the turns in place. The
> silicone adhesive affects it some but it won't crack like
> super glue. Haven't tried Duco cement.
>
> All coils wound with #28 AWG magnet wire.
>
> "Q" at 6 Mhz with all coils measuring 20.5uH (cap 35pf):
> ------------------------------------------------------------------------
> Note #                               1       2      3      4
>
> 1-1/4" Amphenol 5-pin    175    --    175    --
> 1-1/4" amber pill bottle    180    --    177  172
> 1-1/2" amber pill bottle    161  145     --     --
> 1-1/4" untreated paper/   152  130     --     --
>          cardboard
> 1-1/8" PVC                      173    --    175    --
>
> "Q" at 9.5Mhz with all coils measuring 8.4uH (cap 35pf):
> -------------------------------------------------------------------------
>
>
> 1-1/4" amber pill bottle      --     --     187    --
> 1-1/8" PVC                        --     --     180    --
>
> Notes:
> 1 - plain wiring, no adhesives to hold windings
> 2 - use clear fingernail polish to hold windings
>     (strips didn't work, light coat across coil)
> 3 - use Elmer's Stix-All silicone to hold windings
>     (4 strips across coil)
> 4 - use Scotch black electrical tape to hold coil
>     windings (1-1/2 turn)
>
>
>
> 73s  Kees K5BCQ
>
>
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