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AW: LF: "Gain" between qrss3 and qrss10?

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Subject: AW: LF: "Gain" between qrss3 and qrss10?
From: Stefan Schäfer <[email protected]>
Date: Tue, 15 Dec 2009 11:03:47 +0100
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Thread-topic: LF: "Gain" between qrss3 and qrss10?

Dear LF,

I have done some further thoughts/questions about the "gain" between the qrss modes.

If the "gain" or better said SNR between qrss30 and qrss3 is 10dB, so can I do a QSO to VK with 1W TX Power and an antenna efficiency of 1/1000 if I choose QRSS10000000000? That’s a litte jokingly formulated but you know what I mean. In other words, where are the limitations of this rule?

In CW I think that rule cannot be valid because a dot in CW (say 20wpm) is much shorter than 0,3s but to my experience the “gain” compared to qrss3 is not even 10dB. Furthermore a PC must be seen as a source of QRM, especially when connected to the antenna system (e.g. for switching a tx relay with the qrs-programm) and RX (even when using a insulating transformer for the AF), and so it always brings a “negative gain”, even when one uses 10s of ferrite cores…   

And: I always thought of the energy "waste" when applying 1kW (before 6 yrs when I became qrv with a much worse antenna) to the antenna and pumping 999,9W into the earth. But when I need 10x the time in qrss30 to do the qso with 100W, the needed energy is the same (compared to 1kW in qrss3). So, qsos could be done much faster if choosing 10x the power and stay in qrss3. The additional advantage would be, if I try to do a TA QSO I could just stay in the region of 137.7 and those who are qrv in qrss3 and only watch the qrss3-sector would get a nice signal and thus more fascination for the LF-hobby (I often think about the LWLs watching my transmission when no one is answering my call ;-)). In sum, the needed energy (=money) is the same but the needed time would be 10x less.

Of course, there would be some problems like partial discharges due to the high voltage at the antenna and for 10kW the kitchen stove must be connected in parallel, that could cause QRM with the XYL... ;-) But generally it would be interesting!?

What is the maximum power that is applied to an antenna yet? What have you heard yet? I have applied 1kW in a bad antenna (=> abt 100mW ERP), so 10kW would be possible when considering to stay in the legal limit. 10kW would be possible since one doesn't need a ferrite core that has to keep the power (in Class E mode). In USA it would be even more easy due to the fact that the 110V of the mains could just be rectified. Then I would take some STW12NK90Z in parallel and a IXDD414 and try it with 15A antenna current ;-)

Sorry, but in that hobby it is really easy to become euphoric…

 

73 and hope for fine qsos for us J

Stefan / DK7FC

 

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