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The second amp is at ~12mhz.? if the LO to the second mixer is not correct then nothing works. The second LO is in either 33 or 57 mhz (check the docs). The chain from antenna in is 14.0mhz

Henning, Just one more part of the picture but less an issue for lower power. I call that saturation thought its something different.? To many I call that the hockey stick region as it really bends

After hooking up my new Nextion screen and making several great contacts, I was trying to optimize the frequency calibration and? hit the PPT switch a few times with the antenna switch in the wrong

Allison, one more point: for the load always stay off the "knee" i.e. the so called ohmic range. Above this point the MOSFET acts like a voltage controlled (control voltage is the gate to source

Right now we are in a low time of sunspots which is part of the Solar Flux equation that effects our Ionosphere and allows the upper HF bands to work (20 through 10 meters) Until the Solar Cycle

Hello, I upgraded to the KD8CEC firmware last night and I really like it. I see that there is also the uBitx Manager software.? Im guessing that I can backup my existing settings with this software?

Daniel: I have both and I can't really say there's a big difference. One position is save the $50, buy the BITX40, and spend that extra money to upgrade to the best antenna you can buy. On the other

Perfect!? Thanks Allison!? I'm doin it!

Daniel, I'm a bit of a noob, but I have been playing with with various transceivers in receive mode for a few years.? For what it's worth, I can tell you that regardless of the unit, your going to

Air core has one liability that is mutual coupling. So if you use air core the parts must be oriented so they will not couple That means one in each plane of X, Y and Z.? Supporting the Z might be?

The bother I have with most all those curves is that they start at Amperes ....Not mA's ...Been considering generating some on my own, just for fun and enjoyment ...(conductance curve probably) Jim

I'd like to build a few lpfs for my ubitx.? Can I use air core inductors?? I've got plenty of magnet wire and there are lots of inductor calculator online. If this is doable,? Is close wound ok??

Tim, IMD can be caused by two things, saturation at high power and cross-over distortion near idle conditions. You missed one.? Anytime the output is not a uniform multiple of the input. Or what is

Hey everyone! I have a uBitx for few days and I can say that it's awesome! it's my first and only HF transceiver. Yesterday I listened all across 10m to 80m with just few meters of copper wire as an

Jim, Its not only if you do not meet "x" your problems start earlier. Its the difference between ON and "well sorta on" the latter being conducting but not hard.. For commutating mixers (DBMs and

IMD can be caused by two things, saturation at high power and cross-over distortion near idle conditions. I suspect the high standing current prevents cross-over distortion which is why you get better

Mike: I think your criteria may be too narrow. Not all of us are EE guys who understand the nuances of amplifier design. To me, most of the topics you're complaining about seem to make sense to me,

Thanks folks!? I found some good pages on filters to study up on.? Doesn't look too bad.? Think I'll go ahead and build them for the experience points :)

Farhan, I am very aware that fewer devices are desired for better IMD.? ?The key is using competent devices at attainable gains.? There are two problems with 3904s in that role, gain compression at

Allison, Modelling confirmed to me that fewer active devices (and hence higher gain per stage), the better is the IMD. From an IMD perspective, higher gain with high standing current results in better