Last night, I was spotted by LA9IY (1393km) for my best ever TX DX from this QTH on 472kHz WSPR . In all, 10 different stations received me last night on 472kHz WSPR. As usual, I am still using the earth-electrode "antenna" in the ground. Performance amazes me.
Yet again, this proves you do not need lots of power or big antennas on this band. Simple works. QRP rules!
6 Apr 2016
AM and AM Modulation
Someone suggested I put this on my blog, so here goes with a brief introduction.
My favorite method is series modulation using a transistor as the "modulation" stage. The modulated RF stage is set so the stage voltage is close to half rail. With modulation the voltage swings to close to full rail (4 times the power). This stage is followed by a linear amplifier to bring the power up to that required. I used this in my Fredbox and Sixbox rigs without a linear. If I ever do a simple Tenbox AM rig I'd add a linear RF stage.
See Fredbox .
See Sixbox .
Don't forget that if you click on a picture or schematic on my website a larger version is usually available.
AM rigs are simple to build. I am truly surprised that these have gone out of favour in recent times. Surplus PMR AM rigs can often be found for almost nothing. Back in the 1950s and 1960s AM was the predominant mode on HF and VHF.
There is plenty of space for AM on 10m, 6m, 4m and 2m. A decent AM rig should only occupy 6kHz or less of bandwidth.
My favorite method is series modulation using a transistor as the "modulation" stage. The modulated RF stage is set so the stage voltage is close to half rail. With modulation the voltage swings to close to full rail (4 times the power). This stage is followed by a linear amplifier to bring the power up to that required. I used this in my Fredbox and Sixbox rigs without a linear. If I ever do a simple Tenbox AM rig I'd add a linear RF stage.
See Fredbox .
See Sixbox .
Don't forget that if you click on a picture or schematic on my website a larger version is usually available.
AM rigs are simple to build. I am truly surprised that these have gone out of favour in recent times. Surplus PMR AM rigs can often be found for almost nothing. Back in the 1950s and 1960s AM was the predominant mode on HF and VHF.
There is plenty of space for AM on 10m, 6m, 4m and 2m. A decent AM rig should only occupy 6kHz or less of bandwidth.
D-star Cubesat
Southgate Amateur Radio News has a report today of a D-star transponder on a Cubesat. I ahve to admit that I am not "turned on" by these digital modes. It seems to me we are in for a standards war in the coming years. I am happy to sit this one out until the punters decide on one. System fusion, C4FM, D-star, DMR?? Others? Who cares!
See http://www.southgatearc.org/news/2016/april/dstar_satellite_to_launch_from_kourou.htm#.VwTc_L6LWzk.
See http://www.southgatearc.org/news/2016/april/dstar_satellite_to_launch_from_kourou.htm#.VwTc_L6LWzk.
Sunspots and 10m - Wed April 6th 2016
Solar flux is 83 today. Sunspot number is 27 today (K=2). The forecast for 10m propagation is again "poor". After yesterday, I am not expecting much on 10m, but I might get a surprise!
QRT on 630m WSPR and now back on 10m WSPR
After a relatively quiet night on 630m WSPR during which I was copied by several different Dutch stations, I have now returned to 10m WSPR.
UPDATE 0945z: No 10m WSPR spots as yet.
UPDATE 1558z: Still not a single 10m WSPR spot here all day.
UPDATE 0945z: No 10m WSPR spots as yet.
UPDATE 1558z: Still not a single 10m WSPR spot here all day.
5 Apr 2016
Back on 630m (472kHz) WSPR
Since around 1900z I have been active on 630m WSPR. There have been lots of spots given and received. It would not entirely surprise me if my 5mW ERP signal is spotted in Norway again tonight. LA8AV is quite strong here tonight.
Concert - NOT amateur radio
My wife's concert was last Saturday and she spent part of this morning
erasing pencil marks from the many scores borrowed by inter library
loan.She now has a break until the autumn when they start rehearsals again for the 2017 concert which is Elijah by Mendelssohn.
The next concert will be at the West Road Concert Hall. which is an excellent venue in Cambridge. It is where the university music school is located.
The 2016 concert was good and enjoyed by the very full audience who attended.
Sunspots and 10m - Tues April 5th 2016
Solar flux was 82 and sunspot number 23 (K=1). The forecast for 10m propagation remains "poor" today.
UPDATE 0915z: No 10m spots so far, although this is expected as it is still very early.
UPDATE 0942z: G4CUI (172km), to the west of Sheffield, has been spotted on 10m WSPR. He is often spotted here.
UPDATE 1256z: G4CUI spotted again, but no DX on 10m.
UPDATE 0915z: No 10m spots so far, although this is expected as it is still very early.
UPDATE 0942z: G4CUI (172km), to the west of Sheffield, has been spotted on 10m WSPR. He is often spotted here.
UPDATE 1256z: G4CUI spotted again, but no DX on 10m.
2m UKAC tonight
A reminder that the 2m leg of the RSGB's UK activity contest is tonight at 1900z for 2.5 hours. I shall be on with 5W QRP and the big-wheel omni. I seem to be able to work out to about 200km, although I usually only stay on for an hour or less because of my poor voice. 8-10 QSOs and I'm done in!
UPDATE 2025z: After 8 QSOs I was done in. So I stopped after 50 minutes on air. Best DX was the South Coast with G4RUL/P (172km).
UPDATE 2025z: After 8 QSOs I was done in. So I stopped after 50 minutes on air. Best DX was the South Coast with G4RUL/P (172km).
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| 2m QSOs tonight with 5W SSB and big-wheel in 50 minutes |
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