On Fri, 17 Nov 2000, Eric Scace wrote:
>and do not know how the operators were determining bearings.
And Jeff, KH6O added:
>I've been wondering that myself.
To which Milt, N5IA responded:
I will reply with a detailed account of the low band RX antennas and the
occurences at XZ0A after the SS weekend is over.
___________________________________________________________________________
The low band receiving antennas utilized at XZ0A were oriented as shown on
the accompanying photograph of Thahtay Khun Island. One attachment is the
photo and the other is the drawing overlay. They will open together in a
program such as Image Expert.
(Sorry but this reflector cannot handle attachments! de W4ZV)
The antennas were constructed of insulated, #16 stranded copper wire. The
ground rods were 1/2" x 4' copperweld. The terminating resistors were 500
Ohms. The tranformers were 9:1 and all feedline was 75 Ohm RG-6 CATV cable.
The antennas were mostly strung over jungle foilage at a height of 1-2
Meters above ground. At some open locations they were supported by bamboo
sticks. The center of the full sized 160 Meter dipole across the heliport
was supported by crossed, 20' long bamboo poles. The ends were hung in
jungle trees. The orientation of the dipole was from slightly north of East
to slightly south of West.
All feedlines were brought to a common point, split three ways, and fed to
three separate 17 position remote antenna switches. From there, three
separate feedlines went to the operating rooms. In this manner, all
receiving antennas were independently selectable by the 40 M., 80 M., and
the 160 M. stations
All previous comments by Robin, WA6CDR, regarding the performance of the low
dipole on the sunset openings are correct. A couple of evenings of getting
the impression that we were being heard much better than we were hearing
caused me to reflect on the full sized dipole I had installed at XZ1N the
previous year. That antenna had provided some contacts that could not be
heard on the Beverages and EWEs.
I commented to Robin. I am going to try putting a full sized dipole out at
the heliport. I don't think any of the Generals are going to be flying in
and that is the one place it can be done quite decently. I took two of the
2nd wave of operators, just as soon as they had put their bags in their
rooms, and headed out in the afternoon heat and humidity.
Two hours later the feedline was back at the switch boxes and ready for the
evening session. The rest is history. A couple of hours later at the
appointed time, in a matter of less than one minute, the signals from W/K
east coast were there in droves. The signals were barely audible on the SE
Bev as they had been the previous few nights. On the dipole the signals
were layers deep.
EVERY evening, from then until the end of the DXpedition, the scenario was
as Robin described. I will forever remember the last unbelievable night.
When the NA opening was over I went in to Robin's bed, woke him, and while
crying told him of the fantastic occurrences of the past hour and 45
minutes. I was exhausted, exhilirated, and overcome with emotion at the
same time.
This one nearly did not happen. But then that is another story. If any of
you have questions regarding the RX or TX antenna systems, do not hesitate
to ask. I do have lots of digital photos. Have a great Thanksgiving
holiday. 73 de Milt, N5IA
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