Gallery of photos from the VK9NA Dxpedition in 2011. Click any photo to view larger size, with slideshow control options.
November 19th,2011
Amateur Radio |
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I needed to know at what time the sun would be positioned due north, to enable me to validate some previous measurements.
I found the following US Navy website which has a universal calculator allowing you to find this data for your lat/long which can be extracted from your iphone or any GPS.
http://aa.usno.navy.mil/data/docs/mrst.php
For readers in the northern hemisphere, the calculator does allow for north and south latitudes, as well as west and east longitudes…
August 1st,2011
general |
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Recently read some material published by Roy VK4ZQ about his portable station which can be operated on all main amateur bands up to 10 GHz. Worth a read.
July 2nd,2011
Amateur Radio,
contests,
equipment,
Radio |
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Having used some of the WSJT suite during the Norfolk Island VK9NA expedition in January 2011, and following some postings to the VK1 mailing list in recent weeks, I was curious to know how to use WSPR. The best reference is at the website of its author, Joe Taylor W1JT. Having downloaded and installed the software I then had to see what audio levels were suitable.
WSPR is part of a suite of software tools that use digital signal processing (DSP) to detect and decode very weak signals, much weaker than can be even detected by the human ear, let alone understood. Possiblly the best known modes are the FSK441 mode used for meteor scatter contacts on vhf bands, and the JT65 series used for terrestrial dx contacts and Earth-Moon-Earth (EME) contacts on various vhf and uhf bands. The JT65 modes were used at VK9NA.
I first tried connecting a cable from the speaker/headphone socket of the radio to the mike input on the computer. Levels were very sensitive and I had to cut everything down, but even then it didn’t work well. I needed to cut down the audio level output from the radio, an FT817. It was overdriving the mike input of the sound chip in the laptop. If there had been a “line in” option I think that would have worked almost without any further change. The microphone input is more sensitive as it is designed for the much lower level of a microphone. I wired up a potentiometer to enable the sound level going to the computer to be set as a fraction of the output from the radio and that worked very well. I finished up setting that to about 10% of full scale.
The website http://wsprnet.org/drupal/ is the next resource I found very useful. It lists the beacon frequencies commonly used world wide, for each band. I have tried the 7, 10 and 14 MHz bands and found it worked very well. A good read of the user manual is advisable. Adjusting the input level on noise to be around 0 db was quite important. After that it was just a matter of tuning the radio to the correct dial frequency, using USB mode.
Before long I found the screen was gradually building up a list of callsigns received and their signal levels, frequency offsets and the stated power level of their transmitters. Most seem to be 5w but some are less than 1w and one notable station indicated 1000 watts, but was no stronger than others running 5w, so I think he specified his power incorrectly.
The WSPR screen looked like this at one stage today.
WSPR screen, 10.140 MHz
Thanks to Ian VK1HOW for sparking my curiousity about this mode. This must be providing a wealth of data for propagation students.
This is a short contest for QRP operators. It runs for one hour on CW mode, then 1 hour on SSB. A truly easy contest to participate in. All licence classes can participate as QRP (low power) or their ordinary power. The contest was sponsored by the CW operators QRP club.
I wasn’t sure I would have an opportunity to operate in this contest but at about 6:30pm on Saturday 2nd April I decided I should put up an 80m antenna and have a go. At 6:40 I had identified a two section telomast and was measuring out some guy ropes for it. Having found some stakes, guying ring and found the wire antenna cross-boom with the attached halyards and pulleys, I was able to assemble the mast, attach the cross-boom, lay out the guy ropes and do a trial setup to get the guys set to the right lengths. Once that was done I hammered in three stakes and attached the guy ropes to two of them. Walking the mast up to vertical showed I had set one guy at an impossibly long length so it all had to come down. Next time was ok so I could walk the third guy out to the stake and tie it off. One 20 ft feedpoint suspender ready for action. Time about 7:15.
I had a 80/40m dipole assembly last used two years ago at a rental property in Canberra. I attached the centre conductor to one of the halyards and hauled it up to the dizzy 20ft height of the mast. Then I attached some light cords to the antenna ends and tied it to the fence at one end, and to some ground stakes at the other end of both dipole wires. This work was completed in the dark as the sun set at about 6pm local time.
The two dipoles are joined at the centre. This works because the 80m antenna is a very high impedance on 40m, so is virtually “not there at all”. The 40m dipole detunes the 80m one slightly but I went through the adjustment process with this antenna about 20 years ago and have simply rolled it up when I finished using it each time.
Then I got out the FT817 and found a suitable keyer cable, microphone, power supply. On 80m the dipole presented a 1:1 match on the CW end of the band so that was fine. On 3690 it was about 1.3 but my Emtron tuner handled that mismatch with a fairly broad dip. The time now was about 19:45 local and the contest started in 15 minutes, or so I thought.
At 20:00 local time I heard a station calling CQ TEST so I answered, received a number, gave a number, signed off. Good start to the contest, I thought. Then I called CQ TEST myself. No replies. Tuning around showed nil activity. Called CQ again. This time I got a reply from an operator who kindly advised me that the contest was not due to start until 2100 local time. I opened up the computer and checked the contest rules. Start time 1000 UTC, which was 9pm local, but somehow I had reverted to non DST in my calculations due to daylight saving ending later that night. 1000 UTC was almost an hour away. So I had time for some dinner!
About 45 minutes later I went back to the radio and started the contest again at the right time. Signals were strong and most stations were in the vk2, 3 and 4 areas though there were some vk5, vk7 and ZL stations worked too at signal reports of 559 or so. I made 10 cw contacts in this hour. A slow contest compared with the DX contests but it was also quite relaxed and unrushed.
At 1100 UTC the SSB section commenced, operating between 3550 and 3590. Signals were very strong from some stations. Again a few names were exchanged as well as the contest numbers. 15 contacts on SSB, and I got the impression the antenna was working well, as mostly my replies were answered after only one call. Quite good for a 5 watt signal.
I have sent in my log and I don’t think this is the only QRP event I will operate in. This was a very enjoyable process and quite rewarding for the minimal effort required to get on the air. Next time: antenna up another 10 feet. And the ends should be higher too! Should be no problem. I might even do most of the work in the daylight next time.
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Mast and 80/40m dipoles
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Feedpoint of 80/40m dipole
Antennas for 144, 432 and 1296
I plan to operate in this event from home, starting on Saturday evening due to a family commitment that afternoon. I will operate on 144, 432 and 1296 MHz bands only, unless I am inspired to erect more antennas.
Post contest note: I made 40 contacts in the few hours I was able to operate on 144, 432 and 1296. Only a couple of contacts on 1296 but one was to VK2BPK a club station operating from a hill just north of Grenfell. I think that’s the site of the Grenfell 2m repeater. 133km from my location at Yass.
In completing the log and looking at the scoring I noted that the scoring for home stations does not appear to give any incentive for home stations to make contacts with the more distant field stations. The 2 points I get for working a local station on 2m is the same as I earn for a 505 km contact with VK3UHF near Geelong, a much more difficult contact. The purpose of increased points for more difficult contacts is to encourage people to improve their stations and in this kind of contest it encourages home stations to make contacts with distant field stations. There is a full table of scores earned by field stations for different distances. However much the field station may wish to make long distance, difficult contacts, the home stations have no incentive other than their own interest in such contacts. An odd aspect of the rules.
Late comments about the VK9NA expedition I joined in January 2011. This was a VHF/UHF/microwave and 2m EME operation. Due to quite poor conditions for tropo across to the mainland, we eventually did most of the operation on 2m EME. However we did try to make contacts and ran a lot of CQs on 144 MHz every day. We did make some contacts but there were nowhere near the number of tropo contacts made last year. The 144 MHz band was the main band used for this work.
We activated the station every day on 6m as well, from the hotel site.
Due to the high winds experienced on the hill we moved the EME station to the Guide Hall where we had been kindly offered the use of the grounds.
On Norfolk the internet access is provided by Wifi connections at hotels/resorts and a few in the Burnt Pine business area. I found it was necessary to buy several different cards to get access via NIDS, Norfolk telecom and another account for access at the hotel I stayed at. Wifi access from Mt Pitt was good, from the hotel the others stayed at, access to NIDS was not good.
The radio conditions on vhf up were not as good as they had been in 2010. This was partly due to physical weather conditions, including strong winds for the duration of the operation from 8th to 20th January. On the weekend of the summer field day conditions were very poor and the only contacts made with the mainland that weekend were on 6m, and there were not many of them.
The 2m EME operation was very successful. Over a hundred contacts were made using JT65 via the FT897 and a laptop computer running the WSJT software. A TE systems amplifier boosted the output power of the FT897 for EME work. The list of stations worked is at the VK9NA website.
I greatly enjoyed the event. I learned how to use WSJT on both FSK441 and JT65B, and learned a bit about pointing a very large 2m antenna (19 elements, 12 metres length) at the moon and periodically repointing it. For about half or more of the time, the moon was not visible so we were relying on compass bearings corrected for mag offset/declination and an inclinometer for the elevation.
I also became familiar with the FT897 and found what a great radio it is for this kind of operation. The other radios used were FT817 and a TS2000 which I found to be a very good radio too.
The TS2000 has an option to automatically transmit CW at a 700 hz offset (actually the offset equals your selected cw beat note and sidetone frequency) when you switch from USB to CW. It also has an option to automatically switch from SSB to CW mode if you press the key, whether it’s an automatic key or a hand key. Very neat.
Apart from the radio aspects it was also great to get to know Michael VK3KH, Alan VK3XPD, Kevin VK4UH. We were fortunate in being well organised on the social and meals front by Michael’s wife Roz and her sister Gail, and Alan’s wife Aileen all of whom made this event that much more enjoyable.
We did attend a few local special events such as the fish fry, the progressive dinner and the re-enactment drama based on the voyage of the Bounty, the eventual mutiny led by Fletcher Christian and the exile of the mutineers at Pitcairn Island. This history is a proud aspect of the Norfolk Island culture today.
A great event and a fun filled 10 day trip for me.
Here are some photos at Flickr:
Here is one photo of the EME antenna. Remember it is 12 metres long. There are 19 elements. Click the photo for a larger view. 
March 18th,2011
Amateur Radio,
equipment,
Internet,
Radio | tags:
2.4 GHz,
3400 MHz,
Amateur Radio,
antenna,
ham radio,
microwave,
Norfolk Island,
uhf,
vhf |
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For this event I took my usual station on 50 to 1296 MHz, plus my transverter and gridpack for 2403 MHz, Ted VK1BL’s transverter and gridpack for 3400 and Dale VK1DSH’s 10 GHz station (IC202, transverter, dish and tripod).
Contacts were made on all these bands.
Performance of the station on 1296 MHz was not as good as in previous years. This may be due to conditions, or to a problem with my antenna or my location on Mt Ginini. It is becoming increasingly more difficult to find suitable places where even two required directions are not partly blocked by the trees on that mountain.
Some pictures are already on http://www.flickr.com/photos/exposite/sets and I’ll be putting some also onto the vk1da.info photo pages.
December 4th,2010
Amateur Radio,
contests,
Radio | tags:
2.4 GHz,
3400 MHz,
Amateur Radio,
antenna,
contest,
field day,
fieldday,
generator,
ham radio,
microwave,
radio equipment,
vhf/uhf |
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I am joining the VK9NA team for January 2011. All the details of this expedition are on the VK9NA.COM website. This is a VHF/UHF/microwave expedition which will include some 2m EME capability and will have reasonable power (75w) on 5.7 and 10 GHz too.
The station should be on the air by 9th January and will be active in the following weekend’s VK VHF/UHF Summer Field Day event.
More details on the VK9NA website vk9na.com
At the Dayton Hamvention 2010, I attended the VHF weak signal group dinner.
I met and chatted with a number of other people about VHF activities in Australia and heard discussions on contest rules that were familiar issues. Should contest points be based on distance or on grid squares, or power, or what?
In the US VHF sprints they are trying a distance based formula based on 6 character grid locators. They have found that this approach has been well accepted by contest participants. It is now quite feasible to calculate distances based on 6 character locators, since computers are so common. Maybe this is what Australian VHF operators would like. The grid square bonus system is much simpler but some people think it doesn’t give recognition or incentives for longer distance contacts.
It will be interesting to see whether they decide to keep the distance based scoring formula.
May 17th,2010
Amateur Radio,
contests,
Radio | tags:
contests,
scoring,
uhf,
vhf |
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