Topband: HS72B

[Milt Jensen]

----- Original Message ----- 
From: "Bill Tippett" <btippett at alum.mit.edu>
To: <topband at contesting.com>
Sent: Wednesday, December 08, 2004 11:22 AM
Subject: Re: Topband: HS72B

> 1.  Find as remote a location as possible (away from city noise, etc).
> 2.  Find a location where good RX antennas like Beverages are possible.
> 3.  Put up as large a vertical as possible with a good ground system.
> 4.  Try a very low dipole for HIGH angles in addition to #2.  (Beverages,
> Pennant/Flag, EWE, K9AY all being good RX antennas for LOW angles.)

                                          73,  Bill  W4ZV

This is very true on all counts.  At XZ1N in 1998 we were at a hotel within
the city limits of the Capital city of Yangon.  The noise levels were high
and no matter where I constructed Beverages (physical location or azimuth)
we were unable to hear weak signals.  After one week of that I constructed
the full length dipole and strung in UNDER the jungle canopy at a height of
about 3 Meters average above ground.  I made one contact before I left to
come home (only there 10 days) that showed the dipole was capable of
receiving when the Beverages andother RX antennas did not.  Robin had great
success with the sundown openings after I left.  Our transmit antenna at
XZ1N was a 1/4 WL sloper on the north side of the hotel tied to and working
against the large, heavy lightning rod and grounding system from the peak of
the elevator tower 5 stories above ground.

For the XZ0A in 2000 Robin and I were adamant about selecting a location
where the ambient man made noises would be as low as possible.  The island
of Thaytay Khun at the southern tip of Myanmar was selected and proved to be
tremendously effective both on transmit and receive.  For TX antenna was a
full size 1/4 Ground Plane with 12, 1/4 WL elevated radials.  Initially we
installed 8 Beverages, 1 to 2 WL long, for all the primary receving
directions as well as the morning and evening skew paths.  These antennas
were signal split 3 ways and with separate selectors were available to all
three low band stations.

Everything worked FB other than the grayline periods for NA.  After three
evenings of frustration with being unable to copy the multitudes from NA I
remembered the XZ1N dipole and told Robin I was going to add one.  When the
second wave of operators arrived, as there feet touched the island I
commissioned two of them to work with me on this project.  We felt sure the
Generals weren't going to fly in and visit us so we selected the heliport
for the dipole installation, a circular area cut out of the jungle on a
small knoll some 250 Meters east of the hotel.  We constructed our center
support point for the dipole from two bamboo poles, tied together and
erected in an inverted vee form.  The dipole took off at right angles,
supporting the bamboo poles from falling down, and terminated in trees in
the jungle on either side of the heliport.  Average height above ground
level was approximately 5 Meters.  The length of RG-6 feedline was run back
to the signal splitting/switching location.  We finished this project in
about 4, hot, sweaty hours under an afternoon equatorial sun.

BUT, it was worth it.  Just a couple of hours later at sundown the 160 Meter
operator was running stations from the SE USA, all being heard on the dipole
where they were barely discernable on a 2 WL Beverage oriented SE.  The
signals were coming from that direction as that Bev was the only one that
was hearing any signal at all.  The only problem was everyone was bunched
up.  After getting word back to the masses that they needed to spread it
out, when signals were available we worked stations much more easily.

The rest of the story is history of course.  The application of the four
points Bill makes above is exactly what we did at XZ0A.  Results?  Even
though this operation took place at the very peak of the sun spot cycle
(late January & early February, 2000), the operation holds the all time
record for number of QSO's by a DXpedition.  Robin and I firmly believe that
had we done the operation at a sunspot low there would have been 5,000 + Q's
in the log with more than a thousand of them in North America.  See
http://site204.webhost4life.com/g3wgv/fsdxa/Records.pdf .

Anyone wanting to have success with a low band operation from locations far
away from the primary ham population centers of the world should pay
attention to these four points.  If anyone is interested in seeing photos of
the antenna systems mentioned in this post as well as the other aspects of
the XZ0A DXpedition they can view them on my website at
http://www.eaars.com/milt/XZ0A%20slide%20show/ .

Milt, N5IA