On Jul 12, 2018, at 10:19 PM, GEORGE WALLNER <[email protected]> wrote:
Dear Top Banders,
Here is a brief descriptionof the recent Baker Island (KH1/HK7Z) 160-meter
operation.
Among the numerouslimitations the USFWS placed on us, being only allowed on the
island in June was the most onerous. A long way from ideal from a low-band
point of view, but we were determined to make itwork. The result was over 1500
QSO-s on Top Band.
Transmit Antenna and Gear:
The location of the 160 m TXantenna was close to the north-west corner of the
island, but not as far north and clear of the land as we would have liked it.
Also, we were not able to place our TX antenna fully inthe water, due to the
pounding surf. (Which did destroy our 80 m antennathe first night.) Instead,
the 160 m TX antenna stood just at the high tidewater-line, with the metal base
buried in wet sand. At low tide the antennabase was 30 feet from the water’s
edge, but fortunately the sand below theantenna was always saturated with
salt-water. Luckily, the tide was mostly uparound the times we were working NA
on TB. We were only allowed a maximum antennaheight of 43 feet. To meet this
requirement, we designed a “fat” 160 mvertical, which had three vertical wires,
two of them on spreaders to make theapparent diameter of the vertical conductor
larger. The antenna also had two12.5 m top-loading wires, which sloped down at
45-degrees. The antenna had 8 radialsof various lengths, with three of them
going directly into the salt-water. Takeoff to the west and north-west was
clear over open water, but to thenorth-east (towards NA) it was over land, with
a 20’ high sand berm directly inthe way. The antenna was fed via a
remote-controlled coupler. I want to pointout that even this simple, and far
less than ideal, arrangement took atremendous effort to build, as we had to
haul the all the gear for the CW tentabout ¼ mile from the boat landing,
working in 100 degree heat under theEquatorial sun. Transmitter power was
around 800 W (but occasionally reduced400 W to leave more generator power for
the other bands). The radio was a K3S.
Receive Antenna: After thesecond night of operation we built a 60 foot long
DHDL facing north-east. Theantenna had a high-performance filter/pre-amplifier.
After the fourth night weadded a second DHDL that faced towards Europe.
We were expecting easyconditions for JA (who were closer) and difficult for NA.
We got the opposite.The band would open to NA soon after our sun-set (around
18:00 local time) withvery little noise. NA callers were initially weak but
easy copy. Noise wouldstart rising about two hours after sun-set. Fortunately,
that was about thetime the gray-line was reaching the East Coast, which brought
up the signalswell above the noise. Some East Coast signals were quite loud. As
the eveningprogressed, noise continued rising as more of the equatorial
thunderstorms toour west came under darkness. By the time the JA-s would show
up (about 5 hoursafter our sun-set) noise was way up, and receiving conditions
were becomingdifficult. Still, some West Coast stations kept coming in strong,
well over thenoise, and quite able to work among the numerous JA callers.
Occasionally, wehad to listen up for NA above 1825.00 to avoid the JA QRM, but
on the long runthat proved to be unnecessary. Overall, working NA was a
pleasure, whileworking JA (and SE Asia) was a pain due to the noise. By
midnight local timethe lightning crashes on the TX antenna were becoming
painful. Later, the DHDLRX antennas would help, but even then, many signals
were a better copy on theTX antenna. Almost every call was different, some
would be strong and clear onthe TX antenna, while others could only be copied
on the RX antenna. There wasalso a large variation in RX conditions from night
to night. On our secondnight the noise was much higher than on the first night.
Also, as we wereworking progressively weaker stations, things were getting
harder.
Although we knew that thechances for working western EU were basically nil, we
made a big effort to workas far west possible. On most mornings the noise was
just too much to copyanything below S7. A few nights, however, conditions were
favorable, and we gotas far as European Russia. Conditions were the best on our
last night, whenjust at sunrise we got as far west as Serbia, with numerous
Russian andUkrainian stations also logged. (Remember, this was in July!)
After operating 7 straightnights on 160, my ears were ready for a break. We
switched to FT8 for about 5hours, using the regular QSO mode (not
hound-and-fox). With N1DG operating, wemade about 120 NA QSO-s in about 5
hours! Just before midnight, we switched backto CW for the JA-s, who are not
allowed to operate FT8 in the lower part of theband. The FT8 operation revealed
three things: There is serious demand for FT8on TB, the mode gets through the
noise very well and gives modest stations achance to work serious DX on TB, but
it is easily dominated by the strongsignals.
An interesting lesson fromwhat happened to our 80 meter antenna. Initially, it
stood on a sturdy metalbase in the water. During the first night we had a storm
and the surf broke upthe base (snapping ¼” bolts like they were matchsticks).
The surf knocked theantenna down and soaked the tuner with salt-water. The next
morning, we rebuiltthe antenna further up the beach, but without the metal base
which originally connected it to the salt-water ground. Although we added a
good number ofradials, performance was poor, especially when compared to the
160 m antenna,whose metal base was in contact with the salt-water below.
The key lessons learned:
1. 160 m DX is morethan possible in June and July.
2. For good results, you mustbe on the band every night, otherwise you may miss
that special night when theconditions line up just perfectly.
3. A salt-water ground helps,and where possible, vertical antennas should stand
in the water. Being up thebeach is not the same.
4. RX antennas are needed towork the weaker stations.
5. DXpeditions should have astation dedicated to 160 m (at night) with
operators who want to work 160.
6. FT8 is now part of AmateurRadio, even on TB.
Happy DX-ing and 73,
George,
KH1/KH7Z (AA7JV)
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