Thursday, October 31, 2019

Comparison of the FT8 and WSPR modes on 28 MHz - 31st Oct 2019

For the months of May & June 2019, I left the radio listening to FT8 signals on 28 MHz and fed the reception reports up to the PSK Reporter website. With the Summer Sporadic-E season in full swing, it kind of got very repetitive in terms of what was being heard with each days list of stations looking pretty much the same as the previous days.

For the second half of the Summer, I spent a lot more time listening to the WSPR frequency on 28 MHz and uploaded those spots instead. Once we got to September however, the number of reports really began to diminish.

FT8 V WSPR... As an experiment, I tried out both modes today on 28 MHz. My objective was to listen at a time when the band was open and see how the activity on each mode compared.

Session 1... 30 mins of FT8. There seemed to be plenty of signals around 12:00 UTC and this is what I heard on FT8....

Session 2... 30 mins of WSPR. I went to the WSPR frequency and I heard nothing. I could see the odd bit of a signal on the waterfall but no decodes.

Session 3... 30 mins of FT8. I switched back to the FT8 frequency for 30 mins and heard the following...

Obviously conditions had declined a bit from session 1 but I was still hearing signals.

Session 4... 30 mins of WSPR. I switched to the WSPR frequency for 30 mins and heard nothing.

I checked the WSPRnet website and it said that there were 84 stations active worldwide on 10-metres during this period. If I take out the receive only stations then there were just 21 stations in all of Europe transmitting on WSPR on 28 MHz.

Conclusion... Even though WPSR is a fascinating mode, it does require enough users to be operating on the band to make it useful. I'm of the opinion that outside of the summer Sporadic-E season, that critical mass doesn't exist for WSPR on 28 MHz.

Maybe things will be different as we leave the sunspot minimum but it seems to me as if that on 28 MHz at least, FT8 is the only mode that has a critical mass of users.

Addendum : Later in the evening, I heard Mauritania, Argentina and the Falkland Islands on 28 MHz FT8.

Opening on 28 MHz - Wed 30th Oct 2019

The 30th of October was one of those days when I could hear some weak FT8 signals coming from the loudspeaker of the radio and not really strong enough to take much notice of them.

It was a bit of a suprise to see later that the band had been open to Africa and South America during the day

Wednesday, October 30, 2019

Local experiments on 23cms...

Every Tuesday evening, we have a local VHF net in Cork and a few of us get together for a chat. We use the the 6m, 4m, 2m and 70cms bands and which one we use depends on which Tuesday of the month it is.

It usually covers the first four Tuesdays of the month and if there happens to be a fifth Tuesday then we gave it a skip. A few weeks back, we thought it might be a good idea to use the fifth Tuesday in a month for experimentation, to try something that we don't usually do.

From this concept came the idea to try the 23cms band, i.e. 1296 MHz.

Denis, EI4KH near Watergrasshill has a Yaesu FT-2312 23cms transceiver running 4 watts on FM only and his antenna is a 26 element Yagi horizontally polarised.

A sked was organised with Don, EI8DJ who was located in a car at Camden near Crosshaven at the mouth of Cork harbour, a distance of 22 kms or 13.8 miles.

While the path wasn't line of sight, both Denis and Don were in good high locations. EI4KH was about 120m above sea level while EI8DJ was at a spot about 45m above sea level.

As the plot shows below, any obstructions on the path were several kms distant which made them less of an obstruction.

For EI8DJ's portable set-up, he was using a scanner for receive with a home made Bi-Square antenna shown below which was sitting on the dash of his car.

Using a frequency of 1290.000 MHz, EI8DJ managed to hear the FM signal from EI4KH at an estimated S'4' signal strength and a successful 23cms to 2m crossband contact was completed.

EI8DJ found the Bi-Square to be suprisingly directive and later peaked the FM signal from EI4KH to a maximum of an estimated S'7' signal strength.

The experiment was repeated with EI8DJ back in his driveway which is some bit lower than his portable location. From his home location, EI8DJ couldn't hear any sign of the FM signal from EI4KH.

While the distanced achieved were nothing special, it was interesting to see some local activity on the lowest of the amateur microwave bands.

1) The beam heading for Denis was 170 deg.

Saturday, October 26, 2019

Sporadic-E opening on 28 MHz - Fri 25th Oct 2019

Even though it was late October, there was a Sporadic-E opening on 28 MHz from around Europe.

As can be seen from the map, the band opened up via Sporadic-E to Spain and probably linked up with some F2 propagation down to South Africa.

There were some signals from Eastern Ukraine and SW Russia as well. There were possibly F2 but I'd be inclined to think they were double hop Sporadic-E.

Even though we are at the bottom of the sunspot cycle, the band isn't completely dead.

Monday, October 21, 2019

The remarkable rise of FT8

I came across a news item recently with a chart showing the remarkable rise of FT8.

The data for this chart came from the ClubLog system which is used by thousands of people so I would assume it gives a reasonably representative picture.

Saturday, October 19, 2019

Conditions on 28 MHz - Sat 19th Oct 2019

An interesting day on 28 MHz. Even though the solar flux was way down at 66 and we're at the sunspot minimum, it does show that the 28 MHz band isn't completely dead at the moment.

While none of the signals were particularly strong and most were buried in the noise, the band was open. Over the last few days, there have been openings as well so it's worth checking the band.

Monday, October 14, 2019

Signs of the next solar cycle starting...

Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.

At the moment in October of 2019, we are the bottom of the sunspot cycle and conditions on the HF bands are pretty awful. Recent observations of the Sun however show that things are changing.

The image above shows the active regions of the Sun's corona, the outer atmosphere of the Sun. Active regions, solar flares, and coronal mass ejections will appear bright here.

On the 6th of October, two regions with different magnetic polarity were spotted which are part of the next solar cycle.

Back in April, I had a post about a report from NOAA/NASA which said that the end of Cycle 24 and start of Cycle 25 will occur no earlier than July, 2019, and no later than September, 2020. The latest observations tie in with this report.

These observations don't mean that conditions on the HF bands are going to improve all of a sudden. This is a slow process. Over the next year or so, we should begin to see more and more regions with the magnetic polarity of the new solar cycle 25 and fewer with the solar cycle 24 signature.

It's only after we have passed the solar minimum for sure that scientists can pinpoint exactly when it happened.

I would suggest that it will probably be late 2020 before we start to see any real enhancement in the HF bands. Even then, it will be a case of more openings on the likes of 21 MHz rather than 28 MHz.


Saturday, October 12, 2019

Example of BBC TV signal at 45 MHz being heard in South Africa

The BBC recently released this old television clip from 1949 explaining how an amateur radio station in Cape Town, South Africa had received TV signals from the UK.

The map below shows the path which is about 9,700kms or 6,000 miles...

The TV transmitter mentioned in the video was a 405 line transmission from Alexandra Palace in North London. This was vertically polarised with a power of 500 kilowatts (ERP?).

This TV signal had a video carrier on 45.0 MHz and a sound carrier down at 41.5 MHz.

The reception report in 1949 was near the peak of solar cycle 18. As can be seen from the chart below, that was a really good sunspot cycle and conditions were probably excellent on all the HF bands and well up into the low VHF region.

The most likely mode of propagation at 45 MHz was probably multi-hop from the F2 layer in the ionosphere. The maximum usable frequency was probably above 50 MHz so the signals on 45 MHz should have been very good.

It's likely however that with a video signal spread out over three and a half megahertz, the picture was probably very distorted and constantly changing. It should have been possible however to have very good reception of the sound on AM on 41.5 MHz with a dedicated radio receiver.

The radio contact shown in the clip between G8IG in England and ZS1PK in Cape Town, South Africa was probably on 28 MHz AM (note the beam at the start of the clip).

The South African station mentioned that signal were better when things were calm which might infer some sort of tropo ducting. That is unlikely to have been the case as it was very probable that all propagation was via the ionosphere and the weather conditions would have no impact.

All the same, it's an interesting example of early low band VHF TV reception.

Saturday, October 5, 2019

Video: 144 MHz moonbounce with 200w and a 9 el Yagi

In a 45 minute video presentation, KC1HTT in the US shows how it is possible to make contacts on 144 MHz by bouncing signals off the moon with 200 watts into a 9 element Yagi.


The complete station and project is costed at $5,000 but many people will have parts of the station anyway for their 2m SSB station.

The video is a good introduction into what is required to try moonbounce on 2 metres.

Thursday, October 3, 2019

Conditions on 28 MHz - Wed 2nd Oct 2019

I left the radio listening to the FT8 frequency on 28 MHz yesterday and I was suprised to see there had been a reasonable opening. Not too bad considering that the solar flux is down at 69 and we're hopping along the bottom of the sunspot cycle.

As per usual, the main workhorse here is Sporadic-E as can be seen from all the European signals. This allowed me to hear DX signals that were reaching the latitude of Spain.

i.e. F2 prop from say Chile to the Azores and then Sp-E to Ireland.