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.

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.

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.

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.

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.

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

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.

Well it is a big show.  Very big.  Have a look at the Hamvention website and you’ll find maps of the covered exhibition areas and the flea market area which is described as being 9 acres.  I observed that some lanes of what is normally a car park were not fully occupied, and some discussion on the hamvention mailing list (see yahoo groups) indicated that there were many more vendors in the flea market area in past years.

There were over 200 vendors in the covered areas.  The Dayton Amateur Radio Association (DARA) conducted exams for those who wanted to take out a ham licence, or upgrade from Technician or General to a higher grade. Candidates were lined up outside the examination areas all day, Friday and Saturday.  Hundreds must have been examined.

All the equipment manufacturers you have heard of and a lot you haven’t were present with impressive displays of their wares.

New to me were the Kenwood TS590 (HF/6m 100w transceiver), the Flex 1500 (HF/6m 5w transceiver) and the Elecraft 500w power amplifier.

I also saw a rotary 80m dipole on display from Array Solutions.  It looked to be about 50ft or 15m long, with loading coils and loading sections on each end of the dipole. It may have been shorter.

In the flea market there were many hundred vintage radios, ATUs, cables, antennas, connectors, you name it.  My vote for the most unusual item was the F16 simulator.

I came close to buying several new items but eventually just picked up some small components I want for my new antennas, some microwave attenuators and a G4DDK preamp kit for 2.4 GHz.

I met G4DDK at stand 915 where he and Kent WA5VJB were displaying and selling various items including a range of Kent’s pcb antennas including log periodic and skeleton horns for frequencies from 400 MHz to 10 GHz.

The event wound up officially at about 1pm on Sunday.  After that the exhibitor’s area was closed.

I missed out on a great deal I had been offered on an SDR-IQ receiver on Saturday afternoon.  I didn’t realise how many vendors would either close early on Sunday or not turn up at all.  I’ve emailed RF Space and have received a reply already, so all may not be lost.

Dayton Hamvention: well worth going and seeing it, but only if you already have a reason to go to the US.  It’s a long way for 2.5 days of hamfest.

At the VHF weak signal group dinner on Friday night, 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 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.

This time Dale VK1DSH and I operated as a multiop station on 50, 144, 432, 1296, 2403 and 10368 MHz.

Successes:

• Dale made several contacts on 10 GHz with Andy VK2AES operating south east of Bungendore.
• Despite leaving the feed for the 2.4 GHz dish at home, we still made a contact with Andy on that band, using a “field day special” feed constructed onsite from a piece of wire and a N type socket connected to a piece of cable through the dish centre and attached to the normal feed hardware.  Signals S9 over the 70 or 80 km path.
• Several successful contacts with Dave VK2JDS near Bathurst on 1296 MHz. Some persistence was needed for the first contact, when conditions were not so good and we had to get our beam headings right.  More power at both ends would have been a help.
• Other than that, we had a fair contact rate on 144 with many throws to other bands.
• For this event I used one of Owen VK1OD’s Roger Beep boards.  I assembled the board on the previous weekend, mounting the board into a small box with the Icom mike plugging into a socket on the RB box, and mike output to the IC910 through a short section of shielded cable. I set the CW speed to 30 wpm and selected the K option.
• Despite some thunderstorm activity in the area, we didn’t have to shut down.

Activity was a little lower than in the past.  Chris VK2DO was away on a business trip and Matt VK2DAG was roving up and down the NSW coast and unfortunately we didn’t work him once. Our score was just over 2000 points, though, with the help of the additional microwave bands. We were grateful for Andy VK2AES’s efforts in going portable on both days and giving us contacts on all bands, in particular 2.4 and 10 GHz.

VK1DA portable in VHF Field Day January 2010

The field day shack