Tuesday, January 25, 2011


You can read in the side bar of the WSPRnet.org that: QRP for our purpose means 500mW or lower. The last 2 years I thought that 5 watts was QRP, and in the beginning I thought: will anybody ever hear me with 5 watts. But I did, in one year I worked 76 DXCC, most of them with SSB. Everything is relative. Since I work with WSPR and JT65A I know that I can work with 50 milliwatt the same distance as with 5 watt SSB. A discrepancy of 20 db. Thanks to Joe Taylor K1JT for his fine software. Because without the WSPR software we weren’t able to ‘hear’ signals -25 db or lower. I even decode signals with -33 db. I began to think in terms of 5 watt is QRO.


  1. Good morning Paul, I still am at the point were with 5 watts I feel I am pushing super low power...but then again WSPR has been on the back burner with me. I did over Christmas try for a short time to set it up but was just having troubles setting the K3 up to work with it. But with all the posts about it I am getting sparked to give it another go maybe over the weekend.

  2. Hi Paul
    I guess I'm in the same boat as Mike here, I have been running 5w for ages even on CW - I still have the feeling that 5w is on the brink - especially with dipoles and my present End Fed.
    I think we very much need to have higher efficiency antennas for "Very Low Power" My Ideal would be to try a vertical with 120 radials, but space does not permit - now I'm thinking Loops.

    73 Peter

  3. Hello Mike and Peter,

    I run with CW or SSB never below 5 watt. Only with digital modes I do experiments with QRP. QRP is one thing, the other thing is the antenna. I always use moderate antennas. If anything must be improved then it should be my antenna.

    And yes, condx... today is worse. I can hardly make a QSO. I made one with CW on 40 meter. That's all. I quit for today.

    73 Paul

  4. Agreed. 5W is QRO in the WSPR world.

  5. Hello Roger, PA1B Bert made a analysis about my WSPR-ing on 80 meter this week. Between 50 mW and 5 W. It makes almost no difference. Only 6% spots less with 50 mW. Isn't great? 73 Paul

  6. Anonymous1/25/2011

    Hallo Paul,
    De afname van 6%, van het aantal spots treedt op, als je zou reduceren van 5 watt naar 500 mW en als je met 50 mW zou werken, blijven er 47 % van het aantal spots over.

    Overigens, de invloed van het vermogen op het aantal spots, hangt samen met de propagatie en niet zo zeer met WSPR.
    Ik zie een namelijk een zelfde soort verdeling van het vermogen terug, in de QSO's die gemaakt zijn met het laagst mogelijke vermogen.
    Zie: http://a29.veron.nl/pa1b-08n.htm

    De invloed die WSPR inbrengt, is dat door het gebruik van QRSS, alles meer dan tien keer zo langzaam gaat, waardoor het vermogen nog 10 keer zo laag mag zijn. -10 dB

    Groeten, Bert PA1B


Thank you for visiting my website and leaving a comment. 73 Paul

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