David DL1DN has send me a link for his very interesting video.
David made a video in which he reduces his SSB signal from 2.5 W to 19 mW, during a QSO
He reduces his power using an attenuator of 3 dB and 3 attenuators of 6 dB.
An attenuator of 3 dB reduces the power to 1/2.
An attenuator of 6 dB reduces the power to 1/4.
David starts with 2.5 watt (0 dB) and uses a homebrew multiband dipole at 1.9 m above the ground.
The next steps are:
Time Attenuation Pwr Signal
0:15 0 dB 2.5 W
1:30 -3 dB 1.25 W S6
1:42 -9 dB 300 mW S5
2:00 -15 dB 80 mW Video says: -18 dB, but it is -15 dB.
2:14 -21 dB 19 mW S4 or S3
Please notice that every step of 6 dB is 1 S-point.
The receiving OM has an calibrated S-meter, which is excellent for this experiment.
The video shows what happens when the power is reduced.
David transmits but also receives through the attenuator.
Every time that David reduces the power, also the signal of the received station is reduced, so you can hear for yourself what each step of 6 dB does.
As you can hear, listening though the attenuator is absolutely NO problem.
Click here: https://www.youtube.com/watch?v=rvpxyoacrec
Enjoy this very interesting video
For non German speakers:
Wahnsin = madnes
Hintergrundpegel = back ground level
Power Attenuator 1000 Miles per Watt WSPR Propagation Analysis
Working with the Lowest possible power in CW QSO's with QRP and QRPp
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vrijdag 19 september 2014
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Hallo Bert, een heel leuk filmpje. En inderdaad, qua ontvangst valt het me 100% mee. 73, Bas
BeantwoordenVerwijderenHallo Bert, leuk om te zien dat ook met SSB QRP goed te doen is. Phone zit wat QRP betreft een beetje in het verdomhoekje. Leuk om dit op het filmpje te zien. 73 Paul
BeantwoordenVerwijderenHallo Bas en Paul, bedankt voor de enthousiaste reacties. SSB scheelt maar 2 S-punten t.o.v. CW. De veranderingen in propagatie zijn veel groter. Daarom gaat het met SSB ook zo goed. Een inspirerend filmpje. 73, Bert
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