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.

Having downloaded and installed the software I then had to see what audio levels were suitable.  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.

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.

The instruction manual for the generator had several paragraphs about what should be done to improve its efficiency at high altitudes (defined as > 5000 ft ASL). Measures such as fitting a different jet to the carburettor were included in the manual, these being arranged with “your authorised service centre”. When this was mentioned to the seller he said he had never had anyone ask about that for these generators.

So fortunately my money was refunded and I only had to pay freight both ways.

Subsequently my brother decided to replace his ageing Honda generator of some 20 years with a new EU20i inverter generator. I took a look at the manual and found it very interesting reading. Including the paragraph about getting an authorised service agent to install different jets in the carburettor if the generator is to be used at altitudes above 5000 ft asl…

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.

VHF field day antennas

The 8 element yagi for 144 MHz and 16 element for 432 MHz are on the main mast. The smaller mast carries a half wave vertical for 50 MHz, an 18 element yagi for 1296 and a gridpack dish for 2403 MHz.

Operating desk in the tent on Mt Ginini

From left: TS670S and amplifier for 6m, rotator control for small mast, clock for logging, second rotator control, Kbeep box, IC910H for 2m/70cm/23cm, power supply. Paper logs. Power supplies on floor. For 2.4 GHz an FT290R was used.

Field constructed dish feed for 2.4 GHz

The feed you use when the real one was left at home. Made from a piece of stiff coaxial cable, a type N socket a solder lug and some wire from the spare parts box. I knew there was a reason for taking that stuff.

Powered by AFG

Later I made contacts were made with VK1BL/p and VK2AES/p on all six bands (3400 only with VK1BL) but conditions and activity from further afield seemed quite poor with only weak signals from a small number of other portable stations.

I was running my station from a newly purchased inverter generator.  This was not a name brand but an import sold by a Victorian dealer, mostly marketed via Ebay.  I was pleased that its noise performance was much better than my previous generator.  However at about 9pm on Saturday night, within 20 minutes have having its fuel topped up, it slowly ran down and stopped.  All efforts to get it going again were unsuccessful.  I SMSd the other local field stations telling them I had a power problem.  The next morning I could only pack everything up and go home.

What happens to the generator has not been resolved yet.  My confidence in this particular unit is zero.  I have not been able to restart it, despite following the advice of the dealer and changing the fuel to premium unleaded.  I can believe it would run better, but I don’t see why it would simply fail to restart on ordinary unleaded.

I did examine the spark plug and found it was fouled considerably.  The recoil starter still reveals compression is good so I don’t think the rings have given up.  I suspect ignition circuit failure.

Fortunately others didn’t have this problem and went on to make more contacts.  The contacts with Doug 4OE did not work out too well, with Ted VK1BL making only marginal contacts on 144.  Contacts on higher bands were not possible.   Conditions were simply too poor.

Better luck next time.

There have been a number of GMC branded generators on the Australian market.  GMC (Global Machinery Company) was based in China, or was it just an Australian importer of various GMC-branded items?

Mine is rated 950watts, which should really be called 950 VA (volt-amperes) and is powered by a small 4 stroke engine.  My experience of it is that it is a quiet and reliable engine, and the generator produces enough power for my modest VHF/UHF portable station, which requires power for an IC910H and a TS670S plus some minor items like a 40w light globe and a couple of antenna rotators.

My only problem with it was that it produced radio noise at a quite high level, sufficient to require a noise blanker to be run on 144 and be noticeable on 432 MHz.  On 50 MHz it was S9, at a distance of 25 metres between the generator and the 6 metre antenna, an omnidirectional vertical. I tried shielding the entire generator by wrapping it in chicken wire connected to the frame of the generator.  No improvement.

Several other radio amateurs have suggested the noise from the generator is transmitted along the 240V cable.  I haven’t yet proved where the noise is being radiated from.

Last week I put oil into a new Chinese built inverter generator and started it for the first time.  It ran fine and the voltage output displayed as 237 on a DVM.

I found a small engine mechanic willing to look at the GMC generator.  He said the magneto assembly was touching the shaft and preventing it from moving.  He has readjusted it so that it runs smoothly and at about the right RPM.  I have yet to try to calibrate the speed for 50 Hz output but I have a DVM that does frequency among other things, so I should be able to take a low voltage out of my scope soldering iron transformer and see what the frequency is.  For that matter I should check the inverter generator.

The method I used was to load the helical with a capacity hat formed by a short wire, actually an alligator lead I had in my field day accessories box.  I was operating from the car and was nowhere near home at the time.

Here is the SWR curve from the front panel of the IC706, with the radio tuned to 3585 kHz.  The SWR bar-graph is small but the general shape of the SWR curve can be appreciated.  The bars represent the SWR at frequencies below and above the centre frequency indicated by the main frequency dial.  The small dot below the bar in the centre of the graph reminds you that is the measurement corresponding to the dial frequency.  The increment per measurement is 10 KHz, as set using key M2.  The white rectangle drawn around the SWR bar graph was added to the photo by me.

SWR centred on 3585

After adding the loading and retuning the radio to 3521, the SWR curve moved down the band and here it is centred on 3521:

SWR of loaded helical, centred on 3521

A nice application for the SWR indicator and sweep function in the IC706.

This is surprising because anyone who has bought equipment knows very well what they paid, knows what they got and usually has a good idea of whether they got a good deal.  You’d think anyone selling equipment would do a bit of basic research to find out what they are likely to get for a Bloggs XYZ120S transceiver.  But many people don’t do that.  You’d think their precious Bloggs transceiver was gold plated.  They should rethink what it is they are selling.

Radio equipment has a remarkably high resale value compared with most consumer electronics and certainly compared with motor cars we get huge prices for our old radio gear.  Why is that?  Before trying to answer that, let’s consider a few examples of unrealistic pricing or expectations.

One case is a Collins KWM2A transceiver with matching power supply.  These units were arguably the best you could get in their class for about 30 years, from the early 60s to the mid 80s and possibly longer.  They could barely be matched in even one respect by the best any other manufacturer produced.  The reasons – good design, simple operation, no frills, mechanically reliable and electrically hard to fault.  However this gear is now pretty old.  It uses tubes.  The manufacturer does not build these radios any more, parts are now harder to find and are becoming expensive.  Only the true fanatic will continue to maintain and use this type of equipment.  Modern equipment by other manufacturers offers much more in the way of operator conveniences apart from power and space efficiency.  So with this background we see a number of these radios being sold on the second hand market, sometimes with remarkably high pricing.  One ad even stated that since he had noticed similar equipment, together with a power amplifier being sold on Ebay for $US4000.  However he did not nominate an asking price and left it to the reader to work out what he would be prepared to accept. what should it be worth?  What alternatives are there that produce 100 watts on the bands from 80m thru 10m, with say 500 Hz dial readout and one VFO.  Well, almost none on the new market.  Even the cheapest Icom HF radio IC718 offers more facilities for around $800.  So to hope for any more than that is plainly based on the hope that there are people out there that want the equipment just for the pleasure of owning that particular brand or model.  Only the older operators will be at all interested in that thought, yet their numbers are diminishing.  So what chance does our seller have of receiving the $2500 he may think this is worth.  My feeling is, not much at all.

Another example is a portable multimode portable transceiver for the 420-450 MHz band.  This is a Yaesu FT790R.  3 watts output and modes SSB, CW and FM.  This is a curious gadget type radio, with insufficient power to make many contacts at all, unless you are located on the top of a tall hill or connected to a power amplifier.  OR it may be used as an intermediate frequency (IF) radio for higher bands such as microwave bands from say 2 to 10 GHz.  On those bands, using a higher IF is preferable to using 144 or lower frequencies as the IF.   So what is this type of radio worth?  Well, the latest version of the portable low power radio from Yaesu is the FT817.  It operates on all bands from 1.8 MHz to 450 MHz and produces 5 watts of any mode on all those bands.  It has digital readout and tons of memories, an inbuilt keyer and so on.  It is available new for just under $900 and is available on the second hand market for around $600 to $750 depending on age (5 years or 5 days).  So what kind of price should the seller hope to receive for his 20+ year old radio without warranty and spare parts availability.  Would you think $250 excessive?  So would I, but the seller in this example wanted $600 for his old FT790R (including a 10w power amplifier). In my view this is at least double its maximum value.

Another example was someone who should have known better.  A rare piece of Icom VHF/UHF equipment was advertised with a list of all the extras that had been loaded into it.   As my eyes ran over the listing, I searched for the asking price.  I found no clues given except for the amazing phrase “don’t make silly offers”.  Well, what is not silly?  How can a buyer read the seller’s mind and know what he has in mind for an unusual item like that?

In other consumer goods no-one would expect anything for a 20 year old transistor radio, or even a 2 year old MP3 player.  They get thrown on the scrap heap once the next model arrives.  Even more expensive goods like televisions and stereo gear is almost thrown out as worthless at the ripe age of 10 years.

In the case of used amateur radio equipment, you can be lucky and find equipment that has been looked after an used carefully.  The case is not damaged, the electronics inside it are all in good order.  No-one has made non-standard modifications (“improvements”) that reduce its quality of reception or transmission.  You can also be unlucky and find a radio is being sold because someone has discovered it does not work well at all.  With 20 to 30 year old equipment, the work needed to fix some problems can be quite expensive.   However there is currently a high demand for used equipment, which is artificially propping up prices for old equipment that should really be worth $50, not $300.

But what if you do think your Bloggs radio is a fabulous piece of equipment someone will love to use, and get heaps of service from?  Well, the least you can do is to look around first and see what they are selling for.  Be realistic, especially for 20 to 30 year old equipment.

But please, name an asking price and don’t expect buyers to read your mind.