Month: October 2012

CQWW DX SSB preps

Dave Mueller

I’ve been quite busy the past few weeks trying to finish some station improvements before the CQWW DX SSB weekend. SSB is my least favorite mode, but if conditions are good, you can have sky high rates which makes up somewhat for all the QRM. My station works much better on CW, but the WW SSB is one of the greatest contests of the year.

First of all, I had to repair my 80/160m mast. The bamboo was a good idea, but when I pulled a little too hard to try to clear the vertical wire from a branch, it snapped off about 2ft from the top. Down it came and in it’s place I put up 70ft of aluminum mast – somewhat flimsy but fine for the 20-30mph trade winds we get here. Before I pulled the antenna up, I hoisted up my GoPro camera and got some bird’s eye view photos from the 70ft level.

Looking straight down at the tree
Looking northeast toward North America – you can sort of see my 40m vertical next to the ladder in my back yard. The Spiderbeam is nearly invisible in this shot.
Looking due north. There is a slight down slope in this direction, but the fish eye camera lens makes it appear much more than it actually is. All of my Beverage receive antennas are in the jungle beyond the fence.
Looking east – most of the houses are vacant, with the exception of mine (closest to the left) and my neighbor (NH2KD, on the right).

As you can see, the takeoff is not spectacular but is not bad either. The biggest advantage is that this location is pretty quiet most of the time. There are moments when I have power line noise to my south, but there is nothing but jungle to the north.

Once I got the 80/160m antenna back up, I finished building my new remote coax switch. My soldering turned out to be a total mess, partially because I was pressed for time and because I used mostly parts on hand, but it works very well.

dead bug construction at its ugliest!

Essentially, I took my original Beverage switch box built in 2006, and modified it. This switch box uses momentary push buttons to select and latch an antenna, which makes it easy to switch directions quickly. Inside this box is a LM317 with set resistors for R2 to vary the voltage output depending on which antenna is selected. This voltage is then “injected” into the RG-6 feed line through a RF choke and HV capacitor.

At the far end, the DC voltage is “extracted” from the feed line with another RFC, and there a LM3914 chip senses the voltage, selecting an output depending on the value. This output drives a PNP transistor which activates a relay with a 5V coil, selecting that particular antenna. The chip and the relays are driven by a 7805 regulator at the far end. I only use it to switch between 4 different antenna, but it is capable of selecting up to 10. Thus – I am now able to remotely switch between four different antennas on this particular feed line without any additional wires. I do have a second feed line running to the jungle which I still use my standard two-position switch to feed two additional Beverages.

I now can listen in 5 directions: 240 (Africa/SE Asia), 330 (EU/JA), 030 (NA – longer feed line but quieter RX toward NA on 160), 050 (NA – shorter feed line so it performs better on 40/30m), and 110 (SA). I still am planning on installing a Beverage toward VK/ZL before the CQWW DX CW weekend.

CQWW RTTY

Dave Mueller

I operated the CQWW DX RTTY contest a couple weekends ago and conditions on 10 and 15 meters were fantastic. Zones 40 and 33 can be extremely difficult from here, due to the polar path, yet I was able to work TF, CT3, and CR2X which is one of the most difficult countries to work from here due to propagation. This is similar to someone in W3 working UA0 in zone 18 on 10, or a European working KH6.

Conditions on the low bands, however, were dismal. I could get nothing going the 1st night and wasted a lot of time CQing on 40 and 80 for few responses. Everyone was on the higher bands! Tropical systems all around Guam added to the noise, and a strong tropical storm over Japan probably curtailed activity somewhat.

The claimed score is about 1 million points over the Oceania SOAB record – so my goal was met – but I felt I left a lot on the table. If I operate this contest again next year (if I get the 1-year extension I requested), I will have to try to do more on the low bands and try some dual-band CQing. I probably could have added 20-30 QSOs or more per hour had I tried this.

This past weekend was the Oceania DX SSB contest. I made only a few contacts; the EU pileup quickly became unmanageable and unruly so I shut off the radio. We had a threatening weather system that put us in a higher typhoon readiness condition. This meant I had to take down my 80/160m vertical and almost my Spiderbeam. As a result, the station was not ready for a full effort.