Before dark, I tried TXing from one side of the house to the other reflecting my 481THz optical beacon off the windmill. Even by ear in 600 ohm phones the signal was very clear and very easy to find. This was only about 100m path length, but I wanted to check the gear still worked as it is a long time since I used it. Not sure what to try next as I still feel very wobbly on my feet and tire easily. At least I know my homebrew optical gear all works still.

After my very disappointing results on VLF earth-mode yesterday – I must get to the bottom of why results were quite so bad – I think my next test will be at the other end of the spectrum. We have a windmill very close so I may try bouncing optical signals off this to test my optical gear is working still.   It is a long time since I have done any optical experiments.This will not be too far initially, more a test of the gear before venturing any distance.

Well, I did my first VLF earth-mode field test today since my brain bleed in Sept 2013. Sadly, it was a total failure. I am at a loss to explain the results.

Tuned VLF loop

I put the 5W, 8.976kHz, beacon on into the same earth electrodes used successfully on 472kHz (best DX on TX over 1000km) and went about 1.6km to a car park where I always had strong signals using a tuned loop on RX and earth-electrodes on TX from the old QTH in the same village. Nothing at all copied today – absolutely nothing. I waited in case I was in a pause between QRSS3 callsign transmissions, but no absolutely nothing at all. Not even the tiniest hint of a signal.

So I parked in the road about 0.3km from this QTH and again nothing at all. At this point we drove home.

Sure enough, everything was still working at the TX end.  I am using one remote ground and the mains ground as the shack end as for 472kHz. I did check this was grounded to real ground.

So, whatever utilities assistance I was getting before at the old QTH is not the same at this newer QTH. All very very odd. I was expecting to see something. In the past I received transmissions from the old QTH at the new QTH (about 0.3km away) using just an E-field probe on the car. From the old QTH I spanned 6km!

In summary, this VLF test was a total failure. I am at loss to explain things. Not only that, but the work has left me very exhausted. My brain is still foggy, but the results today were not due to any mistakes with the HW gear or PC Spectran settings.

I am not having much success today.

Today I adjusted the turns ratio on my 8.976kHz VLF QRSS3 and 10wpm CW 5W beacon to better match my earth electrodes. At this QTH they look much greater than 50 ohms, which I measured at the “old” QTH and optimised for.

On the way I managed to blow up a TDA2003 IC, which I had to replace. The whole exercise was far more exhausting than I was expecting. It seems that after about 10-15 minutes of physical or mental effort I am done in. Before my cerebellum brain bleed everything today would have been trivial. Now trivial tasks feel like climbing mountains! Although I can see progress in my recovery there is still a long way to go. One of my aims (among many) is to be able to resume field tests as before, but time will tell if I am really up to this: it is quite hard when your brain is still foggy a lot of the time. Oddly, when sitting down at home or when driving things are fine. It is when I do something requiring real physical or mental effort that I get tired. I guess the radio work today was hard as I had not done this sort of thing for some time.

Anyway, the good news is that I hope to do a VLF field test tomorrow.  Everything is ready and tested. It will not be until late afternoon as both my wife and I are busy before then. The XYL will be there at the test site if I get really tired.  Setting up the gear will be especially tiring in my current state. The test site is not too far from home. I have soak tested the TX and it should be fine on QRSS3 using my loop and Spectran at the RX end. I shall report results tomorrow. This will be my first VLF field test in over 18 months. How I have looked forward to this. If the loop is successful I may try the E-field probe.

These days, with dirt cheap kits from China often with free airmail, it is sometimes a wonder that any USA or UK kit companies exit at all. One of these I have mentioned before is Hendrick Kits, which always has a good selection on their website. These are best value if you live in the USA. Several kits are shown as “retired” which I guess means they did not sell well or they had problems with reproducibility. One favourite is the derivative of the BitX SSB design from Ashlan Farhan in India. This uses easily obtainable parts and has been a well proven design. Hendricks sell versions for 20m or 17m.

See http://www.qrpkits.com/bitx20a.html .

It looks like they have just moved so there might we a little delay until early May.

The power out, around 10W, should ensure plenty of contacts. These 2 bands are usually good even when the sun is quiet, so make a good choice. You have to choose either 20m or 17m SSB. I am sure Western kit companies would really value our business. “Use it or lose it”, is a phrase often used about bands. In this case it apples to amateur radio kit suppliers. If we don’t buy from them they will close their doors and cease trading. I am as guilty as anyone having recently bought a 40m Pixie kit from China.

From the Hendricks Kit website:

“The BitX20A and BitX17A are complete SSB kits with board, all parts, digital display and custom powder coated and punched case that is based on the BitX20 that was designed by Ashlan Farhan. The original version was built ugly construction, and you had to source all the parts. I discovered the BitX20 site on Yahoo in 2007, and decided that the BitX20 would be a neat kit for Hendricks QRP Kits. The problem was that it did not have a pcb. A team of Dan Tayloe, Jim Kortge and Arv Evans have worked countless hours making sure that the pcb version was stable and would meet United States F.C.C. Specs. We had to go through several revisions to get it right, and we are happy with the result, even though it took a long time. Some things just take time. The kit includes a commercial quality plated through, silkscreened, solder masked board, and all board mounted parts, plus the polyvaricon tuning capacitor, digital dial, custom powder coated and punched case, knobs and controls. Everything you need to build the kit is provided.
I encourage you to check out the BitX20 users group on Yahoo. They have agreed to provide support for the kits. There are hundreds of messages on there about the history and development of this kit. Our kit puts out about 10 watts, features dual IRF510’s as finals in a push-pull arrangement. The schematic is available at the Bitx20 site on Yahoo. Cost of the kit is $180.00 plus shipping and handling.“

The BitX looks a nice, useful radio. For a beginner it is just about all you need to get started.

Magnetic loop antennas can be very effective, small, antennas. They work well and are ideal for modes like WSPR, JT65, JT9-1 and PSK31 where frequencies don’t have to be moved much. Their main disadvantage is they are narrow-band so require retuning if moving very far in frequency and they are directional.

As ever, Steve G1KQH has been tracking down bargains – in this case motors that could be used to either tune or rotate loops.