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Hi Mike I love Huff Puff circuits. There's no doubt though, this technique is practically-speaking outdated now it is so easy to generate clean stable signals so cheaply with chips like the Si5351A.

Considering the crudities of the termination of the lpf, I'd say that's about right, but more. 73 de Andy

My sentiments are exactly like Jack's. Having also started in 1954 with a Heathkit AT1 and following with all sorts of QRO rigs I now find I'm practicing CW daily so I can work QRP with my 20 and 40

Allison, Taking 2 turns off each, brings it down to 1.5 db @ 14.000 MHZ, and I did normalize the set-up! I have .8 db at 2 MHZ! Phil --- This email has been checked for viruses by AVG.

Andy, Thanks for the help... taking 2 turns off each toroid brings it down to 1.5 db @ 14.000 MHZ. Is this typical ? (I did normalize the test set-up.) Phil --- This email has been checked for viruses

Joe, I agree, far as I'm concerned every milliwatt or db counts if your goal is to have more QSOs and especially more DX QSOs .??? A lot of other things figure in but a little more power or a

As I recall, my first QRP rig (other than my not-really-QRP 15W? Novice rig in 1954) was the CRK-10A, a 40M transceiver. I was amazed at what the receiver could pull in, and all for around $40 at the

Hi Joe, If you are concerned about current drain, drift, AND phase noise you might consider a VXO. Obviously it won't tune from DC to daylight. So many choices, -sigh- 73, Bill KU8H

Hi Joe, My first response was about what QRP *is*. It's about reduced power at the transmitter output and more recently folks think of 5 watts. It is not about the physical size of the gear. Obviously

Its not uncommon to see a 10% variation from one wound iron power core to another.? Add to that even 10% caps and yes they can gang up on you. My first test it to make sure the winding occupies 2/3

Hi Allison All good points, however consider in the context, this is a PTO I am building for my Norcal 2030, a rig which has phenomenal dynamic range and large close in signal handling while sipping

It is pretty funny picturing those kilowatt capable match boxes on a picnic table beside a diminutive QRP xcvr. But food for thought: The QRO guys build those big clunky (but low loss) boxes and run

Generally with PTO radios of the tentec and Drake realm if the PTO is drifting something isn't right.? I start there.? ? Exceptions are Swan and Atlas plus a few older Tentec like the Argonaut 505

Hi Phil, Yes, all discussed before, and the original design is a bit sharp anyway ;-) The TL;DR? answer is to take 1 or 2 turns off each toroid, or try spreading the coils out a bit. That's all you

Hello All! I just built and tested a 20 meter low pass filter. My Rigol DSA 815 says that it's down 1.9 db @ 14.000 MHZ. Isn't that a little too soon? I would think that the roll-off should start

Hi George, Several others have offered links to kits. You may have seen them shortly after you sent this message :) The advantage to kits over scratch building is having all the parts in one place at

Hi R. Tyson Thanks for the suggestions ! The ATU sounds like a great project. ?Do you know if anyone offers a kit version of the one you described.? Thanks George

Hi R. Tyson, I have a pair of Johnson Matchboxes. Those will handle QRP for sure. I have used them at 5 watts and less many many times. They do not even get warm! <evil grin> I also have the BLT that

I would concur. Specifically on the Z match tuner... the Emtech ZM-2 tuner is one that offers good tuning for coax and twin lead, and has the built-in resistive bridge for finals protection while

Antenna, ATU, SWR meter, dummy load ...? ?that's assuming you don't already have all of these. If you do have them - are they QRP versions ? I built a Z match ATU with a resistive bridge. That way