Topband: KH1/KH7Z TopBand Ops Brief

[GEORGE WALLNER]

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)