Hi Mal, since you mentioned 400Hz (I meant cycles per second of course, sorry...) I assume that your are about to bring some wartime airborne equipment back to life. If efficiency is not at highest p
Mal, please have a look at the FACTS at: http://en.wikipedia.org/wiki/Shannon-Hartley_theorem These are the "rules" that all kinds of communications have to obey to when information is sent through a
Yes. My QTH is only 80km from SAQ so I can easily hear the "backwave" signal which is about 17dB below key-down power. As a few kilowatts are leaking out when the TX is idling, I am able to hear when
Stefan, yes, I meant the BW of each Argo pixel. Unless there is QRM strong enough to cause overload, or intermodulation in badly designed audio circuits, there is no need to use a narrow filter in th
Yes, those Trappiste beers are quite interesting, Chimay for example which is available in different signal strengths (QRP..QRO), but I don't believe it is possible to get them in metal cans. As a co
Hi Stefan, Yes, it is not only possible, it is in fact quite simple: When the speed is reduced by a factor K, the information bandwidth is also reduced by the same factor. This allows you to use a re
Yes Alberto, it sounds like the Luxembourg effect. I have a heard a similar effect many times on DCF39's carrier. The high tones of the modulation are attenuated, probably because of some "thermal in
I'm sorry but I didn't do the spelling - I simply forwarded the message I got from SAQ. 73 Johan SM6LKM The reason for the extra transmission is a centenary commemoration of the Nobel Prize given to
mal hamilton wrote (to Alberto di Bene): Mal, a "preferred mode" is actually any mode that works in the current circumstances. Please choose your words more carefully, Alberto is one of the few gentl
Hi Andy, I tried to connect two class E stages in push-pull and it worked as expected. This was a QRP experiment on 160m but I see no reason why it shouldn't be scalable. The even harmonic cancellati
Hi Stefan, yes, a single ended class E amplifier would give the same power with both FETs in parallel but, due to symmetry, the push-pull design has the advantage of cancelling all even order harmoni
Andy, such a doubler will work but the flip-flop is not a guarantee for a perfect 50/50 square wave in this case. The flip-flop will be clocked by both edges of *one* of the XOR input signals, which
Jay, Marcus, LF, When sferics are weak or absent, I often see a "dark band" in that region, even with a nonresonant antenna (for example an E-field probe which is "flat"). Yes, and that is probably w
Yes, of course. It important to remember that 9kHz is still "the lonely dreamer's band". Pile-ups and other "traffic jams" are still quite rare (!) so the risk of misreading a callsign is minimal. Th
Hi Paul, it sounds like your impedance bridge is measuring the absolute impedance (that is Z = (R^2 + X^2)^0.5 where R is the real part, resistance, and X is the imaginary part, reactance). R is prob
