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This is simple, make several soda water dummy loads. Here is Mine. I made mine 1 to 1 SWR. it is dead flat from 160 thru 2 meters. Probably Higher, but don't know because don't have equipment any

Very nice work Dave ! Did you print the whole case or just the front panel attached to a real PRC case?? Looks Great ! Jim WB4ILP

Jerry, The model you posted does not include the 100pF capacitor across the inductor that acts as a second harmonic trap. I also got different inductance values from Toroids.info for the transformer

Hi to get a swr 2, just use a T bnc and put 2 dummy load on it, then they will be in parallel, 25 ohm. The other is to put 2 dummy load in serie, but that is not so easy, to get 100 ohm. 73, oz8pz

bumpity bump

I'm hoping the smarter folks here can help me create some dummy loads with higher SWR's. I'd like to do some temperature delta measurements without putting signals on the air since I want to include

Attached is a revised LT-Spice simulation of the QMX final, also placed under KE7ER under files. There are four separate instances running simultaneously allowing waveforms to be easily compared. T501

Ta1mHS The 10W amp was designed for lower drive levels.? For a QMX to do that and not sacrifice anything There is a need need to attenuate its output by roughly 20db.? To me a waste of

it is solveable<<< You apparently do not understand how things work. -- Allison ------------------ Post online only, direct email will go to a bit bucket.

Only going to use it on 17.

I bought this soldering iron and I love it! 100 Watt. Heats quick and gets hot enough for most work you will have doing kits. I would also suggest looking into getting some good tips for it. I found

That was probably me who used lowercase m for meg ohm. When I'm on my phone proper capitalization sometimes gets by me . Also yes, the 1 M resistor does protect the op as well. I was focused more on

I suspect the topology is wrong on the QMX for a Voltage Mode Class D (VMCD), L502 simply should not be there. Since it is there, it is forcing a constant current into the final, creating the voltage

Hi Jerry, and GM Evan, Evan is correct in all the points he made. Also note that the .asc file he provided includes a model for the BS170 transistor. There is possibly a way to create an L502

Hi Jerry, John Z and I did several simulations of the QDX PA.? The most significant issue is the end-of-transmission spike when the energy in L502 is dissipated by the off state of all four

Hello Hans, Thank you very much, indeed ! I feel much honored. 73 de Aki, JO4MTH Sent: Thursday, February 27, 2025 1:58 PM To: [email protected] Subject: Re: [QRPLabs] 10m low pass filter

The four BS170's and T501 are arranged in a standard voltage mode class D push-pull amp. The center tap of T501's primary is normally a DC voltage source, as it is on the 50W QCX amp. When one set of

I use it for a switch to turn power to the power amplifier on and off. That way I don't have to wait for e.g gps acquisition before the u3s is ready to

Hello Aki Excellent document, very interesting. I hope you wouldn't mind if I put this on the 50W PA page for people to find easily? Attachments in the groups.io forum quickly get automatically

Darrell, I was considering uploading the files to one of those Chinese companies like PCBWay to get a quote for milling the parts from aluminum. I have a hunch that the price might leave me in shock.