Really usefull explanation! you are great in make easy complex things. I apreciate it so much. Thank you for the precious time that you give us in those wonderfull explanations.
Really good demonstration between the maths and real world readings. Much easier to make a calculation of expected tx output using simple mathematical formula. Karl
Nice and interesting as you always are. Aside, I believe that your Siglent awg is capable of giving you two tones from one port. I’m sure it has a combiner itself inside, so you don’t need the external one you made. You might wanna check in the manual. Tschüss
I note that to calculate the average power with two tones, that's exactly the (fallacious) RMS power divided per 2 : (Vpp/2/sqrt(2))^2 /50 /2 (recalling that the signal is between the peaks and 0 half the time, that sounds to make sense)
instead of using a 40db attenuator,it would be possible to use a 1:100 oscilloscope probe connected to the amplifier output and make a direct reading in the oscillocope screen?
I'm confused, so is the Average Power output in watts calculated greater when feeding a dual tone input verses feeding with a same amplitude single tone? Or is only the PEP higher with a dual tone, but calculates to a lower Average Power output in watts when compared to to Average Power output when using a single tone of same amplitude. I was under the previous assumption that PEP power output in watts is the same as Average Power power output in watts regardless of if it is produced by a single audio input frequency or a dual.
Mike K Hi Mike, yeah you second assumption is right. Dual tone means higher PEP power while the Avg. power drops at the same time. You can see it very clearly when you carefully watch my AF experiments. You find the both AF signals adding up. What you see in the AF experiment also happens on RF. Single ton means PEP= AVG while PEP with single tone is lower than on dual tone. This issue still confuses may OM's as it is really tricky. Hope this helps a bit 73
Couldnt be bothered mentioning the 2 resistor values even after a few requests in the comments...now how hard would it be mentioning the 2 resistor values ???
I don't know where the "16" in his "Pavg" formula comes from. 40+ years ago I was taught "Pavg = (Vpeak x .5)squared / Rload", which still works when using his voltages. Vpeak x .5 = Vavg.
Was ich aber komplett vergessen habe , ganz zum Schluss rechnest Du mit 120V wo bei dein Scope nur 1,21V anzeigt und rechts im Bild der Teiler bei x1 steht, ist dort also ein 100:1 Teiler an der Meßspitze geschalten, das geht hier so nicht hervor auch nicht wo das TX Signal dabei abgegriffen wird weil durch den Tastkopf am Antennenausgang wird durch die Kapazität der Messvorgang zum Power Meter doch komplett verfälscht. Ich hoffe dass Du hier zu den Messungen eine kurze Erklärung parat hast für all diejenigen welche das nachmessen möchten aber nicht die Ausstattung haben wie in deinem Lab und ev. mit einem ganz normalen Wattmeter ohne AVG messen werden.
Das ist im Video erklärt Andreas. Hinter dem Sender ist ein 40db leistungs dämpfungsglieder. 40db im spannungsbereich bedeutet Faktor 100. hoffe das hilft. 73
@@TRXLab habe ich anscheinend überhört , habs mir noch mal angesehen und mitbekommen :-) aber schön erklärt. das müssten sich mal viel mehr Leute ansehen die mit den analog Gurken messen und nur einen Ton pfeifen können und dann sagen da kommt viel zu wenig raus! Wenn die dann an meinem LP500 und 2 Ton sehen was da wirklich kommt schaut man immer komplett verdutzt, will es aber dann auch nicht glauben
Well, that's a wrap ! I'll make it simple and easy on myself. I'l just throw away my TI-92 calculator and buy a LP100a. No use to use a formula when using the LP-100 becausev it is all already there. Terrific explanation and demonstratiion!! Thumbs up and thanks for the video. kc5okn
The LP100A is obviously a great meter. But, at $450US that's out of my budget and I assume most small shops and hams. It would be nice if they offered a kit.
+Rudy Rutenber Hi Rudy, yea you are right it is not the cheapest one but you should visit Larry's web site and leave him a message telling about the idea of a kit. He will most likely answer you.
+Rudy Rutenber Well, the gear changed over the years again and again. So I can't really tell you how long it took to set it up that way. Actually I'm again adapting to new needs.
I think your statement is closer to the truth. PEP is the AVERAGE POWER over one cycle taken at the PEAK of the modulation ENVELOPE. This is true whether you use one tone or two for SSB. The issue with one tone is that the output is a constant envelope, single-frequency sinusoid at either the upper or the lower side frequency. SSB transmitters normally don't run at this power on a continuous basis. But if you use two tones, then the amplitude of the two tones must be equal when added together to the amplitude of the single tone. The PEP will be the same, but a power meter designed to measure the AVERAGE power will indicate only HALF of what it was with one tone, since the envelope is no longer constant. To get the PEP, simply multiply that average by 2. The advantage with two tones is the TX does not operate at maximum power on a continuous basis, as it would for a single tone.
Deine Videos sind super, das muss man deutlich mal sagen, jedoch warum nicht in deutsch ? Sehr schwer dir zu zu hören in englisch das würde in deutsch viel besser kommen oder wie wäre es in 2 Ton :-)
Hallo Andreas, vielen Dank freut mich das dir meine Videos gefallen. Leider ist die Videoproduktion eine einmannshow und ich habe keine zusätzliche Kapazität um die Videos nachzuvertonen. Auf der anderen Seite ist ca. 85% meiner Zuschauer englischsprachig. Somit stecke ich ein wenig in der Klemme😀😀 Danke für deinen Kommentar. 73
