Jim,
What I find is each board is different in behaviour. One on my bench now maxes out at 8W on 40M and any more than
4W on 80M results in bad spurs.
Raj
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At 01-03-19, you wrote:
I got my 2nd Version 5 uBITX in the other day. I took the time to build it into a nice case and very carefully wired everything up. I actually made up a shielded "digital" cable using the regular wires and encased them in the silver plated shield from some double shielded RG58 sized, Teflon insulated Coax. I connected the yellow ground wire to the "digital' connector end of the shield and also used another short piece of the yellow ground wire connected between the encoder end of the shield and the encoders ground or "C" pin. The shield only extended to just short of the Encoder and the Key lines and PTT line remained unshielded from that point on.
I built it into the same eBAY case that Jack and Al used for their JackAl builds. I did make an aluminum front panel to make it easier for me to mill out the display window and painted it with 3 coats of Testors blue glossy lacquer. The original case bottom, top and panels were heavily painted and not good candidates for grounding so I removed the paint around all holes in the bottom and steel rear panel. I also grounded the panels using solder lugs and some more of that silver plated braid to a single point ground under one of the standoffs the V5 board was mounted on using star washers and tightened them as far as I could without stripping or breaking the screws. I did make up a double shielded, miniature Teflon coax for the RF output cabling. All other wiring was done as twisted pair or twisted multiple pair wires (including those inside the shield).
I just ran the same exact spectrum test I did on the first Version 5 I received from several weeks ago (the first one was in an open frame aluminum chassis and I did use the twisted pair RF connection between the uBITX board and the SO-239 on the rear panel -- I posted those spectrum data in a previous thread and wasn't really happy with the results.
Here is a picture of the 2nd build and the spectrum plots I got using the exact same setup as for the first version. (I saved the spectrum analyzer setup as a "Preset" so I could, as closely as possible, duplicate the previous tests. BTW I did forget to run the test on 60 meters, sorry about that.
Plots are offered here without further comment for you to make your own conclusions.
Jim Sheldon, W0EB
TSW Project Coordinator and Test Engineer
Raj vu2zap