Thursday, 24 May 2018

"Bumps on the Air" 2018 - QRP in North Norfolk, UK


Today was 2018 ”Bumps on the Air” day for me. Because we don’t have any summits in Norfolk I have to make do with tiny hills, or bumps!

Two years ago Jim G3YLA and I climbed up Beeston Bump (63m) and did some amateur radio operating. This year I wanted to beat that so drove to Norfolk’s mightiest peak – Beacon Hill near West Runton at 100m. Ta dah!

Actually, this wasn’t a very exciting spot as there are just two rotting benches, a flag pole and trees all around.

Nevertheless, I set up my end fed half weave vertical on a 10m fishing pole and connected up my Yaesu FT817. There wasn’t too much about but I worked John F5VKU (also G8MM) near Cannes with 5W SSB. He said he was struggling to hear me.

My 20m QCX radio - click to enlarge any image.
After playing with SSB for a bit and failing to break some pile ups I connected up my 20m QCX radio and tried some CW. I was really surprised as Karl IV3RJH came back to me, 559/549 both ways. I was running about 2W, he was running 3W.

I do have to fix the sidetone on the QCX as calling CQ sounds more like “thump-de-thump-thump-thump-thump-de-thump”. I have the new capacitors, but am waiting for some new BS170 transistors so I can hopefully up the power level to more like 4W too.

But the QCX is an amazing radio for the money and hey, I built it myself, complete with the case and custom label, so any QSO makes me smile.

Another 20m SSB session with the FT817 and I bagged Jack OH3GZ and Juha OH6QAZ.

At this point I packed away and after lunch headed for Beeston Bump on the coast near Sheringham. I’ve written about this before as it has a fantastic view over the North Sea.

Anyway, I put up the EFHW vertical for 20m and set to with 5W CW from my Elecraft K1. This raised Gert OH/DL7UG and Dima RW4C. I then bagged Fabi IK5IiS near Florence.

Also heard were stations in Cypus and Canada, but the Cyprus station on SSB couldn’t hear me and the Canadian seemed to be sending his life story in CW to another station and I got fed up waiting to call him!

I also had a play with my 3W MTR3, but didn’t work anyone as I could see rain clouds coming and decided to pack up.

So not a bad day’s radio. The Elecraft K1 and Yaesu FT-817 worked flawlessly. I think I was getting some RF into the keyer on the QCX as I had trouble sending “/P” – the “/” turned into a right mess sometimes, although I had no trouble sending it on the K1 with the same Palm Paddle.

The moral is that life is NOT too short for QRP!

Tuesday, 1 May 2018

IBP propagation predictions for the UK for May 2018

Propagation predictions for the International Beacon Chain
for the UK, May 2018.
In an effort to try to make HF propagation predictions more accurate I have been playing with a different method of producing them using the ITURHFPROP software.

Previously I had been calculating the field strength of each beacon and then converting that to an S point level. It was pointed out that this isn't the best way and that calculating the signal strength in dBm and then converting it would be better.

They are based on 100W to a dipole at 10m - we know that the IBP chain use a Cushcraft R5 antenna.

I then hit the problem as to what antenna gain do you use. This may sound simplistic, but in fact it isn't as the actual gain off a dipole will depend upon its height, its orientation and the required take-off angle.

Now, the take-off angle will depend upon what ionospheric mode is dominant at that point in time. That is, is it one F-layer hop, two F-layer hops or a combination of E and F-layer hops.

After a lot of thought and discussion I settled on setting the gain at both ends at 0dBi, which appears to give reasonable results - setting it at 2.15dBi gave over-optimistic results

Anyway, attached is the plot of predictions for the beacon chain for May 2018. I'll check to see how accurate it is and adjust the input files accordingly. The ultimate goal is to the transfer these settings to other HF predictions.

If anyone wants to report on whether they find these accurate or not please let me know. They are median predictions, which means some days may be better, some days worse.

Just click on the chart to enlarge it.