Month: November 2012

Mission Complete

Dave Mueller

Earlier this year I decided to try to operate all three CQWW DX contests seriously, to see how I could do.

First, in September was CQWW DX RTTY. It looks like I finished in the top 10 in the world, and broke the existing Oceania record in the process.

Next, in October, came CQWW DX SSB. This was the contest that worried me the most. In 1999 I had operated as KH2/N2NL from KH2JU’s QTH, crashing hard at about the 40 hour mark and finishing with just over 5,000 QSOs and about 7 meg. The station I have put together works well, but I did not anticipate making much more than 5,000 QSOs. It turns out that I did much better than I expected, finishing with over 6,000 QSOs and possibly an eighth or ninth place finish in the world. I fell just over a million points short of Jose CT1BOH’s Oceania record (as KH7R) but it appears that I won the continent, beating a very spirited effort from geographically disadvantaged Hawaii by NH6V at KH6LC.

Finally, last weekend was the CQWW DX CW contest. I had broken the record last year and have all the confidence in the world in this mode (my favorite by far is CW), but I was not looking forward to another 48-hour effort. Once the contest started, however, there was no turning back and when rates were similar to last year, I pushed hard to try to beat my QSO count from last year. I was successful in doing this, making just under 6,500 QSOs and breaking the Oceania record I set last year by over 1/2 million points. It also looks like I may have made the top 10 again, something I am extremely proud of doing from this part of the world.

Contest season for me is over, however I probably will make a few QSOs in the ARRL 160 and 10m contests. CQWW 160 in January is also a fun contest. In the mean time, I will probably continue chasing DX and working the low bands.

Beverage antenna splitter

Dave Mueller

This week I wound a simple Beverage RX antenna splitter – 12 turn primary on a 73-202 binocular core, with a 16 turn secondary center tapped and grounded through a 33 ohm resistor. The idea is to share my Beverage switch box between both radios. This should help me with multipliers on the low bands, an improvement over the past where the 2nd radio could only listen on the noisy low band transmit antennas.

Thanks to N0AX for deciphering my spectrum analyzer for me, but it looks like about 4dB of loss through the transformer, with good isolation between both outputs. Theoretically I could get 3DB loss with a Magic T splitter, but this is fine for Beverage antennas. It seems to work well, and it appears I may even be able to do some same-band SO2R with some of the more remotely located Beverages I have.

The signal was zeroed out to the 50dB line before putting the splitter in-line – shows about 4dB loss on 3.5 Mhz (similar measurements were found on 1.8, 7.0, and 14.0 mhz)

 

Another new Beverage Antenna

Dave Mueller

Yesterday I finally got the chance to install a 6th Beverage receive antenna. The new one is pointed at 160 degrees – about the line separating zones 30 and 32. The new antenna should help not only with VK/ZL, but also Europe long path on 40 and perhaps even 80m. This had to be a short one, about 450ft long, because the housing area and fence meant that I would have to place the feed point deep into the jungle – the deeper I go, the more coax loss countering the performance gain of a longer antenna. I ended up using about 500ft of RG6 to reach the feed point from the remote coax switch that is already 400ft from the shack.

Last night the antenna seemed deaf. While laying in bed – the light bulb went on in my head – I was a doofus and had forgotten to splice the two pieces of wire I used to make up the antenna. Essentially I had been listening on an unterminated, 75ft long Beverage. After I fixed it this morning, the new antenna seems to be hearing normally now.

Here’s the splice point I had forgotten yesterday. A terminated 450ft long antenna hears better than an unterminated 75ft long one!
Yes – the beverage transformer is housed in a Tic Tac box. It’s all I had at the moment, and I only care to keep the transformer somewhat dry and protected from the rain.
Yes – the beverage transformer is housed in a Tic Tac box. It’s all I had at the moment, and I only care to keep the transformer somewhat dry and protected from the rain.
The new wire passes through an area used as a late WW2/immediate post-war dump. These are beer and liquor bottles dated 1945-1947. The Beverage passes through a field of Beverage containers – good luck?

Today, when I finished the splice, I had to clear off a tree that had fallen on my old North American Beverage. The insulators I use allow the wire to slide through them – so tree falls like this normally do not break the wire and allow the antenna to still function.

Nice day in the jungle – sunny and not too damp today
This tree fell when it became overgrown with vines.

While walking the 045 Beverage, I crossed some cigarette butts under the antenna. I had heard a couple gun shots last weekend – pig hunters – but didn’t realize that had been in the vicinity of my wires. Either they did not see them (the #18 cu clad wire is almost invisible) or they are respecting them. Copper theft is very prevalent on Guam but most hunters I’ve seen in the area are responsible people and I let them know what the antennas are for (and that the cu clad wire is almost worthless as scrap). The fact that there are hunters in the area are why I do antenna work mid day, when the hunters are not active (pigs are active in morning and evening) and why I wear colorful clothing and make a lot of noise. I don’t want to be mistaken for a pig or deer!

 

80/160m vertical work

Dave Mueller

Today I completed some work on my 80/160m vertical. My design is somewhat unique, using two parallel vertical wires connected at the feed point – one side is 1/4L on 80m, the other side is connected to top loading wires and is resonant on 160m. The system works very well for me and allows me to share one extensive radial system.

Until today, I always used copper clad window line for this vertical section, because the rigid spacing would keep SWR from fluctuating. I have had lots of problems with mechanical strength however, both with broken wires and some arcing issues if I was transmitting when the wind blew the line into a wet tree branch. This quick arc would burn off the copper cladding, and the steel core would quickly rust, form a high resistance point, and eventually break.

Yesterday I made up a length of homebrew balanced line, using spacers made of 1/2″ PVC sprinkler line which is very light, cheap, and easy to work with. The new antenna should be much more reliable and easy to repair. I also made some extra effort to keep the wire away from branches.

This is the top of the vertical portion of the antenna – left vertical wire for 80m (terminates at the white PVC insulator), right vertical wire continues up to the three top loading wires for 160m.
The feed point has not changed, but you can see the two vertical wires connected together at the feed. The white vacuum relay and coil are used for matching purposes on 160 and acts as a hairpin match.
Here’s the top of the antenna – you can see the new ladder line and the three top loading wires used for 160 and also to support the somewhat flimsy mast in the wind.

CQWW DX SSB results and preps for the CW weekend

Dave Mueller

I’ve been bad about updating this site. I suppose it is a good thing, but I have been extremely busy – but I know there are those who visit here periodically so I need to be better about updating.

The CQWW DX SSB contest exceeded all of my expectations. I had hoped to break 5,000 QSOs – which would match my last SOAB effort from Guam in this contest back in 1999. It turns out that I broke 6,000 QSOs – but fell short of the Oceania single op record. Conditions were good, but not good enough.

Here is the breakdown:

Summary:
Band QSOs Zones Countries
——————————
160: 5 3 5
80: 124 27 35
40: 602 29 67
20: 1227 35 103
15: 2014 35 96
10: 2414 36 100
——————————
Total: 6386 165 406 Total Score = 10,602,889

This score is very close to my CW score from last year. I had more multipliers in 2011, but the QSO total is within 100 or so.

I found a number of small issues with the station during the contest. Most of all, my new remote Beverage switch, utilizing the LM3914, worked very poorly. Specifically, it introduced noise into the feed line, which reduced the effectiveness of the receive antennas. Additionally, the noise floor on my NW and W Beverages was much higher than earlier this year – by 5 or 6 S-units. The European Beverages used to be my quietest antenna, but for the contest it was the noisiest.

I replaced my LM3914 “experiment” with a new design, using +12V, -12V, and 12VAC to switch between four antenna positions. Design is similar to the RCS-4. It works fantastic and all the noise generated by the 3914 IC is gone. I also found and corrected the source of the noise on my NW and W Beverages – a bad connection in the RG-6 cable that feeds these antennas. The bad connection allowed the antennas to function, but high resistance allowed ingress of common mode noise from the shield. Once fixed, my European Beverage is now as quiet as it has been in the past.

Last week I had just finished working PT0S on 40m CW (seconds after sending 5NN) when I heard a loud BOOM of thunder and a loud snap in the shack. I had taken a very close lightning strike. I was completely unaware that a storm had moved in, and lightning is rare on Guam. Turns out I was lucky. So far, the only apparent damage is to one antenna port in my 6X2 antenna switch and the house telephone. I am able to bypass this antenna port – and should be ready for next weekend.

I have a few more things to wrap up this week also before the contest. It’s been busy to find time, because of my work responsibilities as Port Engineer. I have a ship that just entered an availability, so my work load will be greatly increased until the project is complete next February. Here are some photos of the haul out of USCGC ASSATEAGUE, a 110ft Island Class patrol boat based here on Guam.

Looking down at the ship from a camera mounted to the main crane hook about 150ft high.
Divers check out the position of the lifting cradle under the ship
ASSATEAGUE is in mid-air as the floating cranes are shifted around to the pier where the ship will sit until work is complete.