This is just a reminder of the other sites I maintain. Hopefully, you will find some inspiration on these. Overall, I hope you have fun.
http://www.g3xbm.co.uk
https://www.youtube.com/@G3XBM
http://g3xbm-qrp.blogspot.com/
12 Apr 2023
CDARC Wednesday Net
At 1900z on Wednesday evenings, the Cambridge and district amateur radio club (CDARC) holds a very informal net on 145.55 MHz FM. Anyone in range is welcome whether a club member or not. Usually there are between 3 and 7 members on. Polarisation is vertical and there is a web SDR if you are having difficulties receiving. I thought the link for this SDR was on the CDARC website, but cannot find it.
Most people on the net are in the greater Cambridge area (surrounding villages). The net usually lasts for 20-60 minutes, but people come and go as they want. It is rarely technical!
See cdarcvhfrx.hopto.org:8073 for the webSDR.
Matching the earth-electrode antenna in the ground
To allow the auto ATU in the FT-710 to match the earth-electrode antenna on 80m (see the excellent results yesterday) I had to use this transformer. As you can see, it is not pretty!! With it, the load presented to the FT-710 was obviously less than 3:1 as it matched well.
12 years ago
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| Earth-mode experiments in 2011 |
This was my earth-mode signal 4.5km away from home in 2011 at 1.095 kHz using Spectran software on the PC. Strictly speaking, I suppose this is ULF!
It is a long time since I have done any earth-mode experiments, but my health has got in the way. It would be good to do some more experiments.
11 Apr 2023
70cm activity contest
After copying no stations at all (!) I gave up. I expect the next 70cm FT8 activity contest will be much better!
80m FT8 (Tuesday)
As 6m was so poor, I QSYed to 80m FT8 using the earth-electrode "antenna" in the ground. Although I am receiving spots of my signal from right across Europe, it says I am receiving none. This is rubbish as I can see loads of stations locally. Either there is a delay with uploads from me or, more probably, my spots are not getting to PSKreporter. Shortly I shall do reset to see if this cures it.
UPDATE 1922z: The reset did the trick with lots of spots on RX. On TX 36 unique station spots of me so far.
6m FT8 (Tuesday)
In a word, hopeless. I have been on 6m FT8 for about a hour and have been spotted very strongly by just one station not too far away (50km). On RX absolutely nobody copied.
UPDATE 1708z: Still useless! Just 2 stations have spotted me and I have spotted nobody! Soon be time to try another band. I might give 80m FT8 a go with the earth-electrode "antenna" in the ground - probably after tea.
Windmill next door - NOT amateur radio
This stunning photo of the windmill next door was taken by a neighbour K. Tingey.
E-field probes (EFPs)
These are tiny receive only antennas that can work extremely effectively at VLF, LF and MF where external noise is usually the dominant factor. I guess as local external noise is increasingly the dominating factor, these will be as effective as a "big" antenna at even higher frequencies. At LF they can be only a few centimetres long, but be as effective as antennas hundreds of metre long.
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| EFP on a mag mount for 2200m RX |
As the signal decreases, so does the external noise! Overall, nothing is lost. There is no advantage by using a large antenna at low frequencies for receive only. For TX efficiency, a large antenna and good earth help! A popular EFP design is that PA0RDT (Google it). I have made versions for LF and VLF with a tuned peak as shown in the circuit.
See https://sites.google.com/view/g3xbm4/home/antennas/137khz-efp-rx-antenna .
Double rainbow - NOT amateur radio
April in the UK is a strange month. Some days can be warm and sunny, whereas others can be cold. Yesterday was a mix of sunshine and showers. The photo of the double rainbow was taken in haste from the lounge window. A few minutes later it had gone.
10 Apr 2023
630m WSPR RX
At about 1940z, I switched to 630m WSPR RX with the earth-electrode "antenna" in the ground. So far, no spots.
UPDATE 2126z: Several WSPR spots of DC0DX (467km) at up to -9dB S/N.
Earth-mode paper
Someone asked for access to this file. It is now open so if you have this link you should be able to read it. It was sent to me some years ago.
See https://drive.google.com/file/d/16vtYNznORclXJTfpaT-RC7Z3IV8RKqyi/view?usp=sharing .
6m FT8 (Monday)
For about an hour, I have been on 6m FT8. So far, 13 stations have spotted me and 1 have had 1 QSO. I noticed the BNC plug was intermittent. Mending it took about an hour. In years gone by this would have taken me 5 minutes.
80m FT8 (Monday)
At 1255z, I moved from 160m FT8 (no spots) to 80m FT8 using the earth-electrode "antenna" in the ground. The FT8 frequency on 80m seems to be 3.573 MHz.
160m FT8 (Monday)
As my earth-electrode "antenna" is now matched, I am currently using it on 160m FT8 with 10W from the FT-710. No spots, although I am not surprised in daylight. I must double check on the 160m FT8 frequency in Europe. I have never tried FT8 on topband. I have used WSPR in the past. Currently I am on 1840 kHz FT8, which seems right.
UPDATE 1120z: This looks a useful resource for digital modes in Europe. See https://www.pa8s.nl/knowledge-base/frequencies-for-digital-modes/
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| Spots of me at 1814z |
UPDATE 1856z: 15 stations in 7 countries have so far spotted my 10W FT8 on 160m this evening in the daylight. And the antenna is invisible to my XYL!
UPDATE 2005z: My first FT8 QSO on topband with GM8IEM (753km). Although I was in beacon mode and not answering calls earlier, I see I was called by several stations including one in Denmark. 21 stations have spotted me tonight Now QRT on 160m FT8.
Museum open again - NOT amateur radio
Yesterday, after what has seemed a long winter, our local museum and windmill next door reopened. The weather was sunny and pleasant. Parking near our house is not usually an issue. It was yesterday!!
Monday plans
My main aim today is to match my earth-electrode "antenna" on MF. I I can do this, I can try it on FT8 or WSPR TX on 160m or 80m.
Later, I may try 10m QRP FT8 again with the QDX, although it does not teach me much - I know less than 5W of FT8 can get spotted across the planet. All these stations could be worked, but I do not have the energy to chase these!
UPDATE 1021z: After adding more turns to the primary of my 3C90 transformer I can get a perfect match on 160m and 80m with my earth electrode "antenna" with the auto-ATU in the FT-710. I shall try 160m WSPR or FT8 tonight!
2m activty contest (UKAC) last week
Last Tuesday was the activity contest organised by the RSGB. My incredible score (I am joking!!) has just been submitted as I almost forgot. Tomorrow evening is the 70cm activity contest.
The impression I am getting is interest in this contest is waning with the FT8 contest on the following evening doing better. This is pity as it is a very "un"contest contest with people happy to see the activity levels up. I have been taking part for several years.
Earth-electrode "antenna"
My earth-electrode "antenna" has been reinstalled.
Much to my surprise I am unable to tune it using the internal auto-ATU suggesting the impedance is greater than 150 ohms.
I shall have to try a new matching transformer to bring it in range of my auto-ATU. This make take a few goes. I want a good match at MF.
9 Apr 2023
Rain Gauge - NOT amateur radio
One of my wife's Christmas presents was a rain gauge. We record the rain that has fallen each day and total up the month. February was very dry and, so far, in March, we have already had more than the whole of February!
2m Fredbox QSO
This was in 2011 and shows me in QSO with the 10mW 2m AM Fredbox. Many years ago I had a cross channel QSO with it handheld. These days it is hard enough having an FM QSO on 2m!
See https://sites.google.com/view/g3xbm4/home/vhfuhfmicrowaves/homebrew/fredbox.
Grand master? - NOT amateur radio
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| Playing chess with one of my grandsons |
There is no way I am good at chess!
A very useful app is https://www.chess.com/ where you can play against others online or against the computer.
The more successful chess players think well ahead - unlike me!
8m band
This is midway between 10m and 6m. It is only allocated to the Amateur Radio Service and in a few countries it has been allocated for experiments only to a handful of stations. In some cases this is very reluctantly.
It is my view that others could gain access without a licence in the ISM band from 40.66-40.70 MHz as long as local conditions are fully met. You need to convince yourself of the legality. In the UK this means 10mW ERP. On WSPR, this can go a very long way. In Australia 5mW of 8m WSPR has spanned 5000km!
In the next few months in the Es season 10mW ERP will definitely allow UK stations to be copied across Europe on 8m WSPR.
With sunspot numbers high at the moment, the F2 MUF exceeds 42MHz on occasions so very long distances are possible at times with FT8 or WSPR even with QRP.
See https://sites.google.com/view/g3xbm4/home/vhfuhfmicrowaves/8m-band .
8 Apr 2023
Soon to be obscured - NOT amateur radio
Yesterday, some of the hedge on the south side of our garden was cut back. The view of the village church about 300m away is now very good. In a few weeks' time this will be obscured by leaves on the trees.
Now this foliage is cut back I want to replace my earth-electrode "antenna". In a few weeks this will be much harder.
10m QRP FT8 (Saturday)
My 10m FT8 with the tiny QDX transceiver was turned on at 0835z.
UPDATE 1140z: 149 stations spotted and 42 stations have spotted my 10m FT8 QRP today with the QDX.
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| Stations that spotted my QRP today with the tiny QDX |
UPDATE 1909z: 216 spots of my 10m FT8 QRP today with the QDX.
Plans for today
One of my aims for today is to reinstall my earth-electrode antenna in the ground and try it out on MF with the FT-710. I shall probably go on 12m or 10m FT8 with the tiny QDX.
Absent friends?
It is odd how you do not see postings from people you know about for a while and then realise they are not there. Many times there is a good reason and they pop up again. For some time I have not heard from Mike Rainey W1TJ or Jay Wilson W5OLF. Just wondering if they are OK? If you have any news please let me know. They're kind and generous people.
First swallow seen - NOT amateur radio
See the RSPB website for details: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/swallow/
7 Apr 2023
Simple 10m FT8 RX as the Es season approaches
Now seems a good time to remind people of my very simple 10m FT8 receiver, the 10FT8R. Even buying all parts new, I doubt it would cost more than 4 cups of coffee out. It allows the "big rig" to be used for something else whilst keeping a watchful eye on 10m FT8. The design uses low cost crystals and a Polyakov mixer that requires injection at half frequency in a direct conversion RX. The design appeared in RadCom last year. It works remarkably well. My thanks to Jay, W5OLF for doing the schematic drawing.
See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10ft8r-rx .
10m FT8 QRP with the QDX (Friday)
Again, I am on 10m FT8 QRP with the QDX which runs less than 5W. It is now 0925z and I have been on for about 10 minutes. So far, spotted by 1 station 4X1UF (3513km) and 4 stations spotted on 10m FT8 RX.
UPDATE 1550z: So far today, my QRP 10m FT8 spotted by 57 stations on 5 continents.
Oscar 100 narrowband transponder
Every few weeks I like to give an update on activity levels on this geosynchronous satellite by looking at the web SDR at Goonhilly Downs in Cornwall. The last time I looked was late afternoon in the UK on a Thursday. Activity levels remain low.
See https://eshail.batc.org.uk/nb/ .
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