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[IRCA] Vactrol luvin' !!

Where have these things been all my life and why didn't I use them in lieu
of termination resistors (Rt) previously is what I must ask!  With some
good weather today and a drying antenna field I did some work on two DKAZ's
today and reinstalled the Vactrol setup.
I have only one setup from a friend who makes his own for his DKAZ DXpeds.
I will stress that having a multi turn pot or a smaller pot in series for
fine tuning is very useful. No one setting is going to be optimal for every
frequency or deviation from 180 degrees from beampeak but I have found a
setting that seems better than anything I ever could obtain using and
manually fine tuning fixed resistor combos.

Here's some examples from daytime DX today. Locals on 1330 and 1430 are
both at about 102 deg and 13 miles away. My DKAZ aims due west 270 deg so
90 deg should the spot of best back null per theory. 1330 WKTA's ethnic is
so clobbered that I cannot hear a trace of it under WNTA.  Without touching
the Vactrol pot 1430 WEEF's ethnic is also inaudible under WCMY which isn't
strong and has two more stations under it. I've never had nulls this good
or stable on those two before even with phasing!

With the same pot setting, WHFB 1060 at 94 deg is also crushed and WRHL is
basically alone. WLW and WJR aren't strong here days, but they are gone
with the same pot setting and WKZO 590 is basically lost under Omaha's
KXSP. Yes you can get Nebraska in the daytime in NE IL thanx to good ground
conductivity. Note also that Chcago's  WRTO 1200 at 140 deg while not gone
is deeply nulled with that setting. Fun also to have Clinton IA's GYer KROS
1340 dominant.

I'll break out the ohm meter and measure what Rt the Vactrol is providing
tomorrow and likely move the setup to my other west DKAZ as I've been
having trouble getting deep back nulls since repairing it after severe
storm damage.

I'd recommend that anyone considering a terminated loop type of antenna
strongly consider using a Vactrol as it is much faster and easier than
walking back and forth manually adjusting resistances. My Vactrol is
connected to the control unit with two separate wires about 250 ft long and
clearly nulls aren't spoiled. A nice pure resistance is created by the
Vactrol and applied to the termination end.

73 KAZ Barrington IL (35 miles NW of Chicago)
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