It will be interesting to see the responses from others.? Answers vary because there are many variables, as you know.

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And I echo Alan, and add “The best QRO station has…the biggest antenna with low losses, just like the QRPp station”? Remember when Clinton used to say “It’s the economy, Stupid?”? My Elmer used to say “It’s the antenna, Dummy!”

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In this case, you answered a very specific question…good on ya OM.? I will provide a very specific answer.

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You asked: Do QRPp devices substantially lose power from antenna tuners and other peripheral whatnot beyond the concerns of a more QRO system?

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My response: BEYOND the concerns of a more QRO system?? No.? The concerns are the same.? We must look at the entire system to see total efficiency, QRO or QRP or QRPp.? One footnote: as you already know, with QRO the concern is for the ability of the components in the tuner to handle higher voltages from more *power* contained in the mismatch.? But that is the one difference.

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If I was in your shoes, and I was asking the questions, my next question would be “OK, Mr. Dunning, do I need to be concerned about the losses in my coupler in absolute terms, then, rather than relative to QRO?”

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My typical answer, because I am an engineer, is “it depends” and “it’s all relative”

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We need to viewing the entire setup as a complete system, from rig to antenna, we must consider several factors:

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1.?????? What is the SWR mismatch?? Coax losses could be higher than the tuner losses depending on length and type of coax.

2.?????? What are the components used in the tuner at your QTH?? Higher SWR at the tuner will be accompanied by higher loss across the components, but “better” (higher quality, better design) parts will have less loss.

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Of course, the goal is maximum radiated power. Best to illustrate with my example (feel free to stop reading if this is boring, I apologize but it’s my nature).

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Also keep in mind these are guesstimate numbers, not measured.? And for the purists on this board, please don’t flame me if you disagree.? I’m 54, not 24, and I never claimed to be a PhD.? The only thing I ever did claim was for the punks in the neighborhood to get off my lawn.? Feel free to comment/add your observations.

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My setup:

·???????? I am sending 500 milliwatts of WSPR from my rig to an end-fed wire, 100 foot vertical and 32 foot horizontal.? I am transmitting on 80 meters, that’s a half wave long wire.

·???????? I have a remote coupler at the base of the wire, a CG-3000 unit, rated for 300 watts.? Because of this, I can pretty much ignore SWR losses on the coax.

·???????? I am using LMR-400 coax for the 300 feet from my shack to the coupler.? (Yes, that’s extreme, but it’s what I had at the time).? That gives me about 0.5 dB loss at 3.5 MHz, if I remember correctly.

·???????? The CG-3000 is a fancy design that has been tested and found to be fairly lossless (we can assume 95% efficiency with this high impedance load on 80 meters).

·???????? I have 24 radials, 16 x 32 feet and 8 x 64 feet.? Although it is a half wave wire, it does still need a counterpoise.? Not as much as a quarter-wave, but it does have to be there.? With high impedance feed-point, we can neglect the losses at ground in this case and assume a radiation efficiency that is pretty high, like 90%.?

·???????? And no gain at low angles for a vertical wire, so let’s consider that factor of unity

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So in my example above, the tuner losses can be ignored.

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But what happens if we cut the wire down to 16 feet, we jump to 20 meters, move it indoors, use a small length of coax, and use a tuner at the rig?

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1.?????? The wire will have a low impedance (quarter wave at 20 meters is 16 feet), so the tuner will have a harder time to make a match, and our efficiency will go down.? Let’s say 75%.

2.?????? The coax losses will be small, let’s assume 8 feet of coax from tuner to wire.

3.?????? No counterpoise, so the rig and the tuner and the human and nearby objects become the counterpoise.? The radiation efficiency goes WAY down, like to 25% or less.

4.?????? And what about the attenuation of the structure?? That could be minor (5-10%), or it could be huge (up to 50%).

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In this second example, the losses from reduced antenna efficiency and the attenuation from the structure are way bigger than the losses of the tuner.? I would be more concerned about those losses and trying to improve those if possible.

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Hopefully this helps.?

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Oh, and congrats on that WSPR report.? Well done!? Who says there is no propagation??

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Mark Lunday, WD4ELG

Greensboro, NC? FM06be

wd4elg@...

http://wd4elg.blogspot.com

SKCC #16439? FISTS #17972? QRP ARCI #16497

Hello Eric,

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Maybe you can try with smaller steps in menu 8.5.

Start again with 27.004 and move up or down in steps of 1 kHz, or even smaller and see what happens.

If you have the opportunity, check your QCX tx freq on another receiver.

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73, Guido, ON6RL.

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