The Weekend brings more 600m Spots

The Locals responded wonderfully to my request to look out for my signal this weekend plus another new Scottish station GM0UDL in the bag and G4FDD.

30/01/2010 22:44 0.503816 -29 0.000200 GM0UDL IO77vo 630
31/01/2010 21:58 0.503825 -30 0.000200 G4FDD IO93kx 191

From the Local camp G4YKE at 8Km provided a 24 Hour monitor of my signal allowing me to take a look at this close propagation thing. We are line of sight across some undulating fairly damp clay fields with a clump of trees on the highest point just past mid way which don’t completely block the line of sight. I named these trees ‘Fat Lady Laying Down’ ’cause that is what they look like, Morse modulated Light Waves and Microwaves pass down her cleavage, we know we have done it.

31/01/2010 11:30 0.503855 -19 0.000200 G4MZX IO92nd 14
31/01/2010 14:20 0.503847 -31 0.000200 G8EUX IO92md 15

So do my signals vary with propagation at 8km, only 10 Wavelengths distant? It looks like it does, comparing my signal received by G4YKE on a horizontal antenna at 8Km and by M0LMH on a 500kHz vertical antenna at 194Km seems to indicate this.


Next if we compare the signal from the Vertical Antenna of G4JNT received at G4YKE, a distance of 160Km, with that of G3ZJO at just 8Km distant it seems that, whatever the polarisation and angle of radiation from my Antenna is (it is uncertain due to its compact size and surroundings), we suffer similar changes in propagation at the same time.zjo-yke-jnt-zjo


I am not experienced enough on MF to draw positive conclusions, others may be able to say more.

2 more Stations on 500kHz

The close range stuff still continues to intrigue. Finally I have been Spotted by G0NBD and G3KAN, it was my QRSS he spotted the other evening, now he is getting good signals. I think it is too early in the setting up and aerial adjustment period to study what is happening to my signal in the first 5-6Km or so.

28/01/2010 23:36 0.503812 -28 0.000200 G0NBD IO83lk 195
29/01/2010 13:10  0.503824 -12 0.000200 G3KAN IO92nf 5

Spotted by the POLICE or was it the Palace on 500kHz

Well PA0LCE actually, one more added to the list overnight.

2010-01-28 06:36 G3ZJO 0.503838 -33 0 IO92ng +17 0.050 PA0LCE JO21nj 423

423Km, -33dB is just on the edge of possibility with WSPR.

I have also had a report of my QRSS possibly being copied at 6Km. The local distances intrigue me, inefficient antennas mean not much is copied on the band, but I would not have expected much attenuation of my signal at 5 to 6Km.

500kHz Antenna Computer Model ERP

The QRP Kids on 500kHz G3XBM and G3ZJO would hate to be over underestimating, 😀 our QRPp ERP levels.
A few days ago Roger told me he had got more sensitivity out of his Antenna Current Meter and Re – Calibrated it. Funny that, I read his e-mail with my Meter in one hand having modified it for more sensitivity.

I had a FT37-43 ring core in my meter, I struggled to get a decent reading. I have had in mind for some time to try something from the ‘unknown ring core drawer’. In fact some are ‘known unknowns’ from faulty CFL’s, I suspected they were OK for 500KHz and I had tested the Inductance with 1 turn, it is huge. I used one of those cores and the sensitivity is much greater and hence load on the source less.

Well, Computer Modelling done, and some dry weather and no frozen feet this morning, I took my newly calibrated current meter to the garden and measured my Antenna Current as 73mA.

No Loss Conductor Model (Not correct as Ohmic loss is important on 500KHz) – 260uW ERP – Gain 3.09dBi

Copper Wire construction (Correct for my Antenna but fed at ground level) – 370uW ERP – Gain 3dBi

Copper Wire construction and 300mm off ground Feed Point (Real Antenna) – 269uW ERP – Gain 1.48dBi

These figures take into account the accepted 3dB absorption, MMNA modelling will not factor absorption loss at 500KHz. For me anyway.

They tie in with M0BMU‘s estimates using received signal strength too.

Perhaps I should use 270uW as my stated ERP, I don’t know though, that’s only 1 dB.:-/

Now a picture of the Computer Model.

The important Current ‘sticks’ to the Vertical, the Top Load Current, Horizontal, is shown blue,we don’t much amplitude change here either, the concentration of current in the Hat turns it a nice overall blue.

Czech Republic on 500kHz QRPp confirmation

Lubos OK2BVG has uploaded the data from the G3XBM and G3ZJO 1000km busting night.

2010-01-20 22:16 G3ZJO 0.503819 -29 0 IO92ng +17 0.050 OK2BVG JN88ks 1310 814

Two more new stations also, one from Germany overnight.

2010-01-25 01:28 G3ZJO 0.503829 -28 1 IO92ng +17 0.050 DK8ZJ JO54ag 758 471

Also G0API at 185km.

2010-01-25 19:22 G3ZJO 0.503813 -29 0 IO92ng +17 0.050 G0API IO80xs 185 115

More problems with the data, both stations appeared on the Database so did their lines on the Map but they are phantom lines again with Mr Noboddy at the end. I hope its not just me.

That will be G0API then.

And at about the same distance as DL-SWL that will be DK8ZJ. Good job I copied it from the map when I did, no more than 20 mins later it has gone, yet DL-SWL is there and I asked for 24 hours of Spots.

Thank goodness the Computer Data System that looks after my Bank Account doesn’t lose stuff like it.

Current score on 500kHz 29 unique stations in 7 Countries.

500kHz QRP – QRSS sessions

A change of mode on 500kHz brought in some reports.

The Transmitter is the 4MHz Crystal divided by 8, modulated by a 16F628 PIC keyer. The PA is another Complementary Pair Class D, the transistors again ex Computer memory BFY50 and a CV No. PNP Silicon. I have replace the Inverter PA with this design, as used in my WSPR MEPT. Inverters being CMOS are limited to a 5Volt or so supply, I find them fine for HF where tens of milliwatts is used. On 500KHz you have to start to push them, the added current produces heat in the Voltage regulator but not much in the chip. This is totally wasteful, if I am going to burn my hands I want to do it on the RF device no the PSU.

I have built this TX with the Altoids tin in mind, each unit is on a board cut to fit the noble QRP enclosure. I had the Dispensers at the local chemists smiling the other day when I bought more mints and told them I only wanted the tin really, “they have a worldwide following you know”. “Yes sir, fine, keep taking the pills won’t you”.

It would be impossible to put the whole thing in 1 tin, so we have 3 modules, Keyer – RF Generator – PA. Ah! Happiness is a warm Altoids Tin.

The PA does not quite run as much power as the WSPR one, maybe it is the drive waveform, I have not worried about it as 500mW RF into 50 Ohms is just right.

The first session brought a nice report from G3XBM, interesting as we still have not managed to get a WSPR signal to him. There must be an answer to that somewhere.

Next G3CWB in IO91rm, BTW its downside up, read the bottom line.

Super signals at M0BMU, he is my standard by which I judge my performance, the first, and only for a while, station to receive my QRppppp when I first started with a dubious antenna.

G4GWT is at a fair distance in IO83qo 188.9 km or 117.4 mls. Captured at 1245utc on 24th January.

There may be more reports to come today, if so I will add them later.
A report was received from Mark GM-SWL, he sent some grabs which are pretty surely my signal although not enough information was clear for a positive report. Also after dusk Rik ON7YD copied my call several times.

Thanks to all reporters, unlike WSPR, you had a choice and put in some effort to spot the signals from IO92.

New Calls and Distance Record on 500kHz

Last night produced another Phantom Line on the Map. This time a line terminating in nothing goes up near Telford. However there is a new Spot on the Database which must be associated with it. Therefore I have done the labelling work manually.

Computers and their foibles don’t we love them aye?500k-map-231


I have also added to the map the Spot sent by e-mail by Lubos OK2BVG, I must ask him to add this to the database. I think that due to the RX being at his Portable location and he at home, Spots were not automatically uploaded.

Conditions on the 20th were superb G3XBM and I were keen to exceed 100Km on the band, Lubos OK2BVG went to the trouble of driving to his country QTH with a nice quiet background and installed his RX and Computer so that he could monitor from home. Now that is real Han Spirit.

I am not into claiming records / firsts for anything, this must be a good one though for the QRP involved and the distance.

It is 1310Km, according to the Loc.Distance software and equates to 6,550,000 Km per Watt of ERP.
In old money that is, 814 Miles, 4,070,000 Miles per Watt of ERP.

Estimated ERP is a difficult subject, I am prepared to accept that the actual power could be up to 10 dB more than stated. Well that is still peanuts and I am the lowest power on the band.

QRP don’t we just love it aye ?