73

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Mitch N0DIM ()

Billy,

My $0.02, having built (1) QCX+, (2) 50W PA, and (2) QDX, is what others have said - carefully read the instructions, watch any videos, and then follow the instructions. Hans has done an excellent job writing them. I would emphasize the use of a magnifying device of your choice and the thorough use of a DMM so as to check for solder bridges, cold solder joints, and then for the toroids, I suggest checking not just the solder joints, but the next joints in line - I've had cases where it appeared that I had continuity, but it was actually just with the wire itself - it did not have a good connection to the pad - so follow the traces and do your continuity check at the next pads (does that make sense?).

Also, for the toroids, I have found that the best way (for me) is to install the toroid and to either mark where the solder joint will be on the wire with a Sharpie, remove the toroid and (at least mostly) scrape off the enamel - I use a box cutter - and then reinstall and solder OR, particularly for the larger wires, scrape the enamel off with the toroid/transformer?in situ. A key note is that that extra 1" or so of wire (you know, the excess so you can snug things down? :-) ) will act as a heat sink, so I scrape the enamel off, tack the wire in place, and then trim the excess down to 0.25-0.5" - long enough that I can both hold it with a pair of needle nose pliers (when really snugging things down, else they're a real heat sink!) and still solder. Speaking from experience, removing that 'heat sink' wire and removing as much enamel as you can before you solder is the way to go for the larger wires. For the smaller wires, I use a mix of that method and Hans' method of burning off the enamel?in situ. Ultimately, it's whatever way works best for you :-)

Finally, have fun! Breaks are allowed and a rested mind can catch things that a tired mind might miss :-)

Regards,

Charles Johnson
KF4AYT

PS I echo what has been said about this forum - for the most part, this is a SUPPORT forum, so while there are shared tips and 'watch out for this' messages, it is only natural that you'll mostly see 'problem' messages.

PPS Particularly for high density boards, I highly recommend a vacuum-operated desoldering gun. In addition to letting you target just THAT one pad, it reduces the amount of time heat is applied to the PCB. I don't recall how much I paid for my Hakka 808, but it's worth every penny!

Good evening everyone, I agree with what Jerry wrote, the WSPR propagation does not determine the openings in SSB,

I wonder why WSPR is less effective at VHF?? Is it due to the more rapid fading as opposed to the almost 2 minute frame for WSPR?

I may have a simplistic view, and I hope to be corrected, but it seems to me that an EER method can only reproduce a single tone at a time. The code tracks the loudest frequency and duplicates. The wave shaping circuit changes the volume. ?This can not generate a true two tone signal.?

The real trick to understanding this will be to develop an understanding of the IQ representation of RF signals. Seeing what an FM signal looks like on an IQ diagram, and seeing what an AM signal looks like, and understanding why those signals look the way they do, is really the key to understanding the fact that every arbitrary signal can be broken down into FM and AM components.

Surely this just amounts to creating? at any given point in time only one sampled frequency
and then switching to another fast enough in order to give the effect of two or more
simultaneous tones ?

In an analogue system? then ALL the tones of speech are present simultaneously.

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- 73 de Andy -

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