Tricks in the art
By Mark Connelly
hcdx list, September 4, 2000
On Saturday, September 2, 2000, I stopped in at Vern Brownell's
QTH (W1VB) on Eastward Road in Chatham, Cape Cod, MA.
Vern has recently become interested in medium-wave and his house
is right on a private beach: ideal for DX.
One purpose of my visit was to consult on a good antenna system
for medium-wave DXing. There's a reasonable amount of land between
the house and the beach, certainly not enough for a Beverage but
adequate for two 50 m (160 ft) wires, one northeast and one southeast.
This is the first system we rolled out.
I had a phasing unit with me and I told Vern that by combining
the two wires through the phaser we could generate a good east-
west cardioid pattern that, if set up for the west null, should
give a good 120-degree wide sweep of DX targets from Europe and
the Middle East on the northern end to Africa and Brazil on the
southern side of the optimum pick-up zone.
It soon became apparent that electrical noise carried on
house wiring was too high in amplitude - about S8 - for the wire
antenna system to work. The noise could be totally nulled with
the phasing unit, but using phasing for that took away the real
objective: nulling out pesky New York stations and other unwanted
broadcast interference from the west. Sometimes a noise null might
coincide with a "pest" station null, but more often it didn't.
Maybe you'd even be nulling desired DX instead. The results would
just turn out to be a "crap shoot" with little predictability.
Connecting the two wires through a balun reduced the noise a little
(down to about S5) but that took the nulling option away unless
a third antenna was introduced. Vern and I concluded that even
this level of noise was excessive. We connected the "beach ends"
of the two wires to change the "vee" into a horizontal triangle.
Signal levels were slightly higher but the mains noise still wasn't
low enough for weak-signal DXing such as during aurora or during
initial (1 hour or more pre-sunset) Trans-Atlantic fade-ins. Certainly
it wasn't good enough for 160-m ham DXing where the signals are
orders of magnitude weaker than the big European medium-wave broadcasters.
I still knew that there were some "tricks of the trade"
that could work. Even that "mecca" of MW DXing Cappahayden, Newfoundland
had some electrical noise issues that had to be solved. One of
the visitors at Vern's mentioned that he used to work for a power
company in Pennsylvania chasing down sources of electrical interference.
All of us know that the degree of cooperation that power companies
give to hams and radio listeners can vary greatly. It is often
in the power company's interest to find and eliminate noise sources,
more because the noise often emanates from their own equipment
that may be in the early stages of a possibly catastrophic, dangerous,
expensive, and service- interrupting failure. The threat of FCC
intervention (in these days of a relatively toothless agency)
is probably a secondary concern at best.
Vern and I went around the house with a transistor radio to see
if the noise peaked up at any single spot. The worst of it was
at the circuit breaker box (unfortunately quite close to the ham
shack) and we concluded that the RFI was probably riding in on
the mains from an outside source. The power conduits are underground
but that didn't seem to make much difference in the immediate
vicinity of the house. Perhaps Vern's friend can help him eventually
deal with the power company.
In the mean time, I knew that I had a good chance to eliminate
the noise pick-up by using a balanced loop antenna at least 15
m / 50 ft. behind the house. I installed the 1.8 m per side square
single-turn broadband loop (BBL-1) that I use on the roof of the
car during beach DXpeditions. The loop was aimed for east-west
and positioned about 15 m behind the house along the border between
the lawn and a low cluster of pitch pines and red cedars just
above the beach. We turned on the Drake R8A after deploying the
loop and "voila": very low noise. Weaker daytime groundwave stations
were now out of the "muck".
We still wanted to have another antenna available to allow
nulling of domestic stations to the west. The wire antenna that
we'd installed was too much of a noise "picker-upper" to be of
much benefit. I knew that a right-angle two loop system: one aimed
northeast and the other southeast would work very well into a
phasing unit adjusted to knock out westerly stations. I've used
a similar set-up at other house locations where longwires were
totally useless because of local electrical noise.
By this time it was about 6 p.m. local (2200 UTC) and skip
was starting to build. I had the broadband loop feeding channel
1 of the phasing unit and the noisy wire arrangement going to
channel 2. For cruising the dial, I left the unit set for reception
from the loop only. Not surprisingly, Saudi Arabia - 1521 was
the first Trans-Atlantic "out of the box" with a heterodyne against
WGAM/WWKB/WTHE-1520 at 2210 UTC and good room- filling audio by
2225. This is about an hour before sunset. Other early arrivers
included Algeria-981 and Libya-1251. Vern had a R9000 receiver
on the other side of the room. He brought up good Libya audio
on that: just about as clear as what I had off the loop on the
R8A. I asked him what antenna he had attached to the R9000: after
all it didn't seem to be picking up much noise. The antenna was
a ham band (VHF, I think) coax-fed vertical groundplane. I said
"Let's phase that against the loop". Noise problem solved ! We
could now DX seriously. I "walked up" to one NYC station after
another and then "bam !" nulled them into the dirt. I had Croatia/Spain-1134
louder than "next door" WBBR-1130. Morocco-1053 was blasting in
at S9+30 next to a feeble remnant of nulled WEVD-1050. We were
ready to rock.
Vern and I cruised the dial from 7 to 9 p.m. EDT (2300 to 0100
UTC). I didn't write anything down, but I know we heard, as a
minimum, the following signals: Algeria-549, Spain-585, Canaries-621,
Spain-639, Spain-684, Spain-774, Egypt-819, Azores-836, Canaries-837,
Italy-846, Spain-855, Egypt-864, Canaries-882, Algeria-891, UK-909.
Spain-918, Spain-954, Spain-972, Algeria-981 (and later possible
Greece), Spain-999, Canaries-1008, Spain-1026, Morocco-1044, Spain-1044,
Morocco-1053, Spain-1080 (almost equal to WTIC !), UK-1089, Spain-1107,
Spain-1116, Spain-1125 over Croatia, Spain/Croatia-1134 even mix
... huge!, Spain-1143, Spain-1152 over possible Romania, Canaries-1179
slightly over a big jumble (Sweden?, Greece?, Romania?), Spain-1197,
unID-1206 (low audio), Spain-1215, UK-1215, Spain-1224, unID-1233
prob. Morocco, Libya-1251, Spain-1296, Spain-1305, Spain-1359,
Spain-1413, Germany/Algeria-1422, Spain-1485, unID (Saudi Arabia
or Belgium)-1512 in WNRB slop, Saudi Arabia-1521, Spain-1521,
Kuwait-1548, Algeria-1550, unID-1557 (France ?) in WQEW hash,
Spain-1575, Spain-1584, Spain (EI)-1602 big (stronger than WUNR/WWRL-1600).
The best signals were in the mid-band (1000 to 1200 kHz) segment.
Low band conditions were poorer by comparison.
Latin Americans were weak: even RVC-530 wasn't too good.
I left a bit after 9 p.m. so Vern could get back to his guests
and I could get over to W. Yarmouth to sleep before going home
early the next morning. I'd been up since 5 a.m. and would be
arising at the same time on Sunday.
Most likely Vern will have me install a phasing unit and
at least one low-noise loop over at his place on a subsequent
visit. He told me that he'd probably join the National Radio Club
soon and that he's likely to show up at some of our monthly Boston
Area DXers meetings in Lexington, MA. The mind boggles at the
DX logs that will be possible from Vern's excellent location on
the shore in Chatham, not far from old (now-deactivated) WCC.
Who knows - maybe a "delegation" of the Boston Area DXers might
show up down there in the winter for a DXpedition. They used to
go up to Chamberlain, ME for this.