2020-01-19

Winter VHF Day, In Ringsted.

This annual winter VHF day takes place in the second half of January, and if I am not prevented by a family occasion, I will usually be going.

This year had a bit of a theme on OSCAR (QO) 100.

A nice presentation by OZ2OE and OZ5N showing some simple and less simple home construction projects for receiving the down link on 10GHz, as well as different versions of an up-converter to 2400MHz, ranging from some older home made (and modified for the frequency) 13cm equipment to a setup made with low cost Chinese modules.
OZ2OE was presented with an award, the VHF profile of 2019, mainly for his work on publishing information about how to get on the QO100 satellite.

Another presentation on the GPS control by Bo, OZ2M, I did not attend, but it does relate to QO100, in the sense that knowing your frequency (TX and RX) makes the satellite operation much more convenient, and with narrow band digital modes it is a necessity.

As usual, it is always a pleasure to meet friends, old and new, so I had an excellent time there.

2020-01-06

2m Tropo Over The New Year's Period.

Though I have had the cough and not too much energy, 2m has been good to me, mostly via FT8. When the voice is not good, it is a much better mode, and it is excellent for monitoring the propagation.

2m:
Coming back home on the 27th (I think) I noticed a cluster of spots from Southern France, all within a period of 10 minutes and in a relatively small area. This I consider a sporadic E opening, as other stations i Europe were working Es via a reflecting "cloud in the same area. My first experience of 2m Winter Es.
In the same opening LX1JX was worked as a new DXCC on 6m.
28th provided QSOs with 3 G stations and a PA. Not spectacular, but not too bad.
2nd January, just a single QSO on 2m with LY5P
5th gave me quite a surprise: I saw EA2XR in my FT8 display, only 17dB S/N, but I tried anyway. Much to my surprise he answered my first call, and the QSO was made. The surprise is more so, because he gave me a better report than I gave him: -6dB S/N. My guess is that I must have been lucky that he had his antenna precisely in my direction, and that his receiver is top notch (EME system?)
On 10m S01WS was worked.

All through this, I am surprised of the results using an omni-directional (Big Wheel) antenna on 2m, a long, lossy cable, and ... no preamplifier. There is plenty of room for improvement.

This is not a bad start of 2020.

2020-01-05

2020 Has Started, And A Brief Look Back On 2019.

For me, 2020 started in the sign of the cough. It stared e few days before the New Year, and is still there, though it seems to be subsiding now.

2019 was a year of travel, and not too much radio activities.
The QO100 geostationary satellite was activated, and the amateur radio transponder went on line in February. I got a decent system up and running for receiving the narrow band transponder down link. This is actually not too complex, as a TV satellite LNB is sufficient for converting the 10GHz down link signal from the satellite. A bit of modification, and adding an external reference oscillator placed indoors proved necessary, was constructed and has been in use since then. An improved version is in the making.
Next step is - still - getting to transmit on the 2400MHz up link for the satellite.
Also on 10GHz, a simple experiment has been running: Using a LNB for reception of terrestrial signals, via rain scatter and tropospheric propagation. I am still impressed that I receive a beacon about 36km from here, certainly non-line-of-sight. It is there all the time, received with the LNB alone, no extra gain from a dish.
Also, a fair amount of sporadic E openings over the summer on 6m and 4m, with a few new countries worked on each band, and getting a fair amount of components for projects (mostly via eBay).
Not too many projects finished, and many more ideas appeared. It is a fact of life that getting ideas is easy, putting them into practise takes much more time.

2020 should probably see me finishing just a few projects, like:
- QO100 uplink capability
- receive antenna system for monitoring several frequencies simultaneously
- some QRSS activity, mostly grabbing (receiving) QRSS signals  and other weak signal modes

The beginning of 2020 (and the end of 2019) has seen some spectacular tropospheric propagation over the Atlantic.
On 2m the European distance record was broken for tropo signals, with a spectacular QSO between Cape Verde and Northern Scotland.
On 70cm the world record was broken with a QSO from Cape Verde to Scotland.
All this has been made possible by using weak signal modes, like FT8. I would not be surprised if those records will be broken again later this year. Exciting times on VHF and UHF, and possibly the microwave bands.

Happy New Year to all from here. Hope to work some of you guys.

2019-12-27

A Brief 10m QRPP Experiment.

A local amateur, OZ5AR has started taking the challenge of low power seriously. I should do the same.
He started building a simple circuit, yes, it is just an attenuator. The output (and therefore the attenuation has not yet been measured, and he did not tell me the value of the series resistor part, so I do not yet know how low his power was. Calibration needed.
The signal went from about S5 down to an easily readable CW signal with practically no S-meter output.
We have both tested the lowest power output of our standard rigs, the IC-7300 and the IC-7600, and measured it to be between 700 and 1500mW. A more precise measurement is needed.
The distance between us is almost exactly 2km. My challenge is to see the minimum power necessary to make a contact, and preferably go below 1mW. A contact like this would actually qualify for an award: The 1000 miles per Watt Award. Just for the fun of it.
The initial test is on 28.322MHz, a frequency to which a "standard" crystal oscillator is available. The frequency (+/- the tolerance of the oscillators) is also used by Italian stations for very low power QRSS transmissions.I do have attenuators available to reduce the power from 1.25W to approximately 1mW. More when I have had the time to find everything. The next few days are quite busy with going on and receiving visits.
Yes, we will test as many bands as we can, but the experiments will have to finish some time next year. For some bands, like 472kHz a transmitter needs to be built.
I would like to do the experiments with home brew transmitters (and, over time, receivers), just for the fun of it
Yes, yes, never running out of ideas ...


2019-12-25

Idea Box: QRSS With Simple Home Made Equipment.

Some years ago, while living in the Netherlands, I made a few experiments in receiving QRSS (very slow morse) with a receiver and a computer running the SpectrumLab software under Wine in Linux.

Despite living in an apartment I had some success, but when I moved everything was dismantled.

I have still been following the developments in the QRSS activity, and I should like to get going again. Running a so-called Grabber (QRSS receiver does not take too much time out for other activities, because the spectrograms are simply up-loaded to a website for all to see.
QRSS provides a quite good weak signal performance, so it is usable for propagation monitoring, provided that there are some QRSS transmitters active.

Last time I was running a QRSS Grabber was before the time of the low cost Raspberry Pi single board computer, but these days it is an excellent candidate for running grabber software.

Now, what about receivers ? I was thinking of running a very simple, low cost receiver to begin with, e.g. a modifies Pixie kit.
The Pixie is an extremely simple 40m single frequency CW transceiver, mostly supplied with a 7023kHz crystal. On 40m it just might be capable of running a grabber on 7040kHz. The "IF" will be 17kHz, that should be within the capabilities of spectrum analysis programs for the Raspberry Pi. Alternatively, a different crystal, say 7030, 7035 or even 7038kHz crystal could be used, substantially bringing the "IF" down. If the missing image selectivity becomes a problem, a simple, single crystal filter with a 7040kHz crystal filter could be used.

To be fair, the Pixie is very low cost, a kit can be had for less than $5, so it is an excellent candidate for experiments. The design, however, is probably quite reliable, but certainly not high performance.

In the coming year I hope to have room for some experiments with QRSS, but a higher priority is getting a signal through the QO100 satellite.

2019-12-24

More Solar Cycle 25 Sunspots.

More sunspots from the new solar cycle 25 have appeared on the sun.

Today Spaceweather.com announced that two spots from cycle 25 have appeared showing in the solar disk.
This is the first time this cycle, and suggests that the Maunder minimum sometimes predicted in solar activity is not imminent. The Maunder Minimum was a period of decades without sunspots occurred in the 17th century.

This quickening appears to show a normal cycle 25, with a predicted maximum in mid-2025. The current minimum is, however, considered a "deep minimum", usually occurring once a century.

I am very much looking forward to more sunspots and therefore bettewr propagation on the higher bands.

Christmas present from the sun ? ;)

2019-12-23

Construction Style For Home Made Radio Equipment.

We are approaching the Winter Solstice holiday season, and I do not expect to be blogging much in that period.
Therefore, I will take the opportunity to wish you all Happy holidays, Merry Christmas. Happy Hanukkah, or whichever holidays you may want to celebrate at this time of the year.

Now for a little bit of radio:
I was watching some Youtube videos on home made TRXs, by ZL2CTM. He has a very neat style of home building using modules built on strip boards, then mounting on the copper clad side of a un-etched PCB (single or double sided). This should make for some quite good RF construction practice, at least on the HF bands, maybe on the lower VHF bands.
He uses old fashioned non-SMD style components, but actually surface mounted on the strip board. There is no reason that it could not be adapted for SMD style components, too, if space is at a premium, or for higher frequencies.
I have a good amount of strip boards ("Vero Boards"), some "island" boards, and some blank PCBs, so it is possible to start.
I also have some "island" experimental boards with a ground plane on the other side, this could potentially be used for higher VHF, and maybe, just maybe for some 432MHz experiments. This should prove an interesting experiment. Some RF shielding would be in order, though.

So what should happen here in the holiday season and next year ?

Now, I need to finish some projects and get my stock of components and PCB modules in better order. This process has started, but it needs to continue.
Then, I should probably start this by use the construction style mentioned above for the QO100 control boxes, outdoors and indoors. Will need a shielded box or two, too, though. After all, some of the frequencies of the system are in the 100s of MHz range.

How soon will I finis the next project ? We shall see.