I hooked up the dummy load to the signal generator output and measured Vpp with a scope in the mV range for a signal! That seems to me to be quite low! The output from the synthesizer looks OK Vpp wis

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Syd, So the output is loaded by 50 Ohms. This is what I see. I'm no expert but has the 85 Ohm output impedance of the Si5351 anything to do with this? 73 Alan G4ZFQ

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Can you elaborate? How are the "generator" and "synthesizer" different? Are you measuring the output of the si5351 from different points? More info is needed, at least by me, to understand what you're

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With a scope the output of the synthesizer IC clocks look good on the scope,somewhere around 3+Vpp at the clocks. When I put a dummy load on the generator output the signal is significantly lower than

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Hi All I believe QRP labs AN 006 has the info. you require. Regards Mike G6GN

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Right, those are for the LPF switch kit which is unused for the Sig Gen/VFO kit. Keep in mind that the PCB used for the SIg Gen/VFO is also used for the U3S and Clock kit, so it's got stuff you won't

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It's for this, no? https://www.qrp-labs.com/ultimatelpf

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I'm looking at the construction manual of the signal generator: pages 2 & 4. Page 2 is supposed to be the "schematic" and page 4 shows one view of the main PCB layout. Page 4 shows a connector that ha

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Well in the process of checking and reflowing joints, and checking values I managed to short something. Good thing I have added a current limiting supply to the workbench. I need to try and track that

#qcxmini #problem

No worries at all, Ryan, and kudos to you for being so gracious about it; in my mind that pays for a whole year of "whoopsies" :-) On a side note, I wrote the mini informal description because many he

#qcxmini #problem

I stand corrected, and wonderfully so. I'm going to have to take more time to read and digest your response in full. I am the first to admit there's a lot I don't understand. I try to stay within my s

#qcxmini #problem

He said he's seeing signal voltage at C22 and C23, so Q7 isn't the problem. He also says he's seeing signal voltage at the junction of R37 and R30, and that's definitely a problem, because as I said,

#qcxmini #problem

Sounds like your trouble is in this part of the circuit: Did you put the correct part in for Q7? It's a BSS123 not BS170. I'd also check that R51 and R52 didn't get damaged during construction, and re

#qcxmini #problem

Hi Bryan, If you're seeing a signal on the input side (I presume you mean the inverting input to the op-amp at pin 6) of R38 and C23, there's a problem: that's a classic op-amp summing junction, at wh

#qcxmini #problem

Julian, Didn’t have a few minutes until late tonight. I verified that R247 is 0 ohms. I am seeing 700Hz on the scope at C21-> C22 -> R37 -> R38 and C23 on the input side of them. Not seeing the tone o

#qcxmini #problem

Good, then, Brian, "we're one down and one to go". You mentioned in your first post that you saw an AC voltage a the top and the slider of the potentiometer; did I correctly interpret your notes? I ho

#qcxmini #problem

Julian, Thank you. I had missed the DVM Power hook up bridge. Battery indicator is functioning now. Thanks for pointing out the pin out numbering. I was rushing to get out the door and felt I had some

#qcxmini #problem

First thing = easy thing: did you connect Pin 1 to Pin 3 on the DVM/Pwr meter header area ? Next thing, your IC pin numbering is the wrong way around: pin 8 is 12v (nominally), pin 4 is gnd. With that

#qcxmini #problem

New build of a QCX mini for 20m. Rev 1 board. I get no audio out. Adjusting the pot results in varying output on the middle lug of the pot. I can track that output through the mating connector. 3.8V m

#qcxmini #problem

Finished building the 40m mini. Smoke test went good. Everything ok. Working my way through alignment. 2nd step.. Adjustment of IQ Balance... R27 is kaput (furthest left blue trimmer. Tried heating up

#qcxmini #problem