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Yeah, it doesn't make much sense. I was thinking about RF in the shack - RF sometimes does strange things. I put the amp on the bench just to look at it and measure the quiescent, which is 228 mA.

That seems hard to achieve. Maybe you are over driving the amp and possibly also the tinysa. If you have an attenuator available, see if the harmonic drops more than the attenuation. Curt

Vic Interesting misfortune. A 500w amp remains on my wish list. Switching diodes and maybe even transistors are often even more vulnerable when not biased. I am thinking try using the leaded parts

Thanks for reminding me, Arv. I used to know this stuff pretty well, but that was over 40 years ago. Time to review. In the meantime, I took the uBITX and the amp off the desk, lest I be tempted to

Frequently there are comments regarding the proper bias setting for transistor amplifiers (BJT and MOSFET). For SSB, in order to minimize spurious emissions you want to operate your finals in the

Characterizing the Chinese amp/LPF with the TinySA... Second harmonic not too bad. THIRD harmonic OTOH is consistently 10 dB higher than the fundamental! Think I need to look at the biasing on that

So my adventure with the CCLPF ( cheap Chinese...) continues. I started by characterizing the existing filters with a NanoVNA. Enjoying the learning curve on that one... The 80M was just weird -

I've had a BitX40 since 2017, and blew the driver transistor sitting on the bench not even connected to an antenna when my 500w amp was running, so I installed the back to back protection diodes and

IF you really REALLY want to use these preformed jumpers. . . copper plate the tips first - silver plate would work, too.? Probably a lot more bother than precutting your own jumpers from the same

Is it possible you are trying to solder to aluminum or steel pins crimped on the ends of the wires? Those may be more difficult to impossible to solder. Gordon

I am using the ones that come as kits of wires, cut to various lengths and with the ends preformed for insertion into solderless breadboards like these: Preformed Jumpers ( http://postimg.cc/Dmr3p4xb

Finally got a microphone hooked up to the uSDX this morning and spent the day making contacts!? Slick little radio, for the price, but I like the uBITX better for base station duty. But, once I get

What wires are you using? Are you re-purposing male-male jumpers w/ pins on the ends or just raw wire cut to fit? Ken, N2VIP

Cheap wire probably heavily oxidized

I have several different brands of the jumper wires.? In all cases, when I try to solder these jumpers on the protoboard, it is nearly impossible to get the solder to wick onto the wire surface even

Can you go into a bit more detail on the troubles you're seeing when soldering the current breadboard wires on the protoboard? -- -Chris

I have been breadboarding using solderless breadboards and preformed jumper wires.? I can buy protoboards that have the same hole pattern for more permanent applications.? However, when I move the

I'll see if I can google around and find the article again. Tom, wb6b

Not the ceramic ones, you get xtal ones.. a little pricy but sharp stopbands. Basic ones are 7.5 KHz, I am sure wider ones are there. Probably in 21.4MHz.

Raj, I evaluated a few 10.7 mhz fm filters. Their stop-band rejection was hardly 50 dB, not enough for HF radio. Btw, the sbitx scheme does not stop using a narrow cw crystal filter. The entire IF