[HCDX]: NEW ANTENNA SYSTEM + weekend DX

[wa1ion@xxxxxxxxxxxxx (Mark Connelly)]

I put a new antenna system to the test last night (Sunday, 28 SEP)
and it worked even better than expected.  This consisted of two 
MFJ-1024 active whips to the further-modified (Al Merriman take 
note !) MFJ-1026 phaser.  The MFJ-1026 phasing unit had all of
the initial modifications, as documented by my previous E-mails
and by DX News (vol. 64, no. 30 ... date: 22 SEP 1997).  

The MFJ-1026 was modified for this by providing an extra main 
antenna input jack (RCA phono) that was tied to the regular main 
input through a 0.1 uF DC-blocking capacitor and to the +12 VDC
line through a 2.2 mH Mouser high-current RF choke.  This allows 
+12 VDC to be fed out on a coaxial line to one of the two active
whips.  The existing RCA phono jack that is associated with the 
Auxiliary input (tied to the corresponding SO-239) was altered to 
run to the SO-239 via a 0.1 uF capacitor and to +12 VDC through 
a 2.2 mH choke in a manner similar to the added Main input phono 
jack.  The reworked Auxiliary RCA phono input can now pass power
to, and accept RF from, "active whip #2".  

The trick to making this system work is to provide a physical 
separation between the two whips equal to at least 1/16 wavelength 
at the lowest operating frequency.  I set the system up at the house 
in East Harwich (Cape Cod, MA) with each whip fed by 22 m (72 ft.) 
lengths of coaxial cable.  Coaxial cables ran out a south-facing 
window, one off to the east, the other to the west.  Because of 
short lengths of cable inside the room, the actual distance between 
the MFJ-1024 whip east of the house and the one west of it was 
about 40 m (131 ft.).  This is about 1/16 wavelength at the low 
end of the MW band.  When the phase is correctly adjusted on the 
MFJ-1026, cardioid patterns with a null to the west or a null to 
the east can be produced.  The null to the west is of most use in 
my situation, unless I want to hear a ballgame on a domestic that 
is being severely trashed by an Algerian (a not-uncommon occurrence 
on Cape Cod !).

Nulls of domestics to the southwest / west / northwest, even pesty
short-skip New Yorkers, set up beautifully.  The 1220 to 1490 section 
of the dial, with many domestics per channel, was a "tough nugget", 
but other frequencies were eminently DXable.  Hets on the car radio 
well before 2200 UTC / 6 p.m. local (before sunset) told me that the 
TA's were going to be screaming as soon as the real DX gear was set 
up.  "Everything and its mother" was piling in on the TA channels 
below 1200 kHz.  I'd have to rank the best catches as Syria-827, 
SER Spain on 810 kHz (// 792) sometimes beating CJVA and nulled WGY, 
and Italy on 900 kHz (// 846) mixed with CKDH and CJBR (FF) with the 
other 900 kHz domestics pretty much absent from the "playing field".  
Reception UTC times: Spain-810 @ 2219, Italy-900 @ 2251, Syria-827
@ 2356.  The heavy hitters from Spain, Morocco, and Algeria were 
"body-slamming" the R8A with S9+40 signals.  WABC-770 was sometimes 
weaker than ...and slopped by (!) ... Switzerland-765 and 
Spain/Egypt-774.  Morocco-207 longwave was quite useful to parallel 
with 594, 819, and 1053 (all of which dominated their respective 
channels with big signals much of the time).  The Arab North 
Africans all the way from Egypt to Morocco were generally huge 
and ran roughshod over any attempted co-channel competition from
UK and German stations.  Egypt-864 roared in, ruining any chance 
at hearing the Irish low-power pirate.  After 0600 UTC would work 
better for this.

So that's it for the story of the "phased vertical array" (and 
we're not talking broadcast towers here).  The 2-whip array is
broadband for easy parallel checking and "frequency agility".  
This should be a useful system for beach DXpeditions at sites 
with insufficient space for Beverages, but adequate room (and 
privacy) for setting up something better than the typical 
vehicle-mounted loop / whip cardioid array.  Though the loop / 
whip set up works well, it requires varactor tuning that can 
slow you down during a "killer" opening.

Mark Connelly - WA1ION
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