On Thu, Dec 14, 2017 at 03:55 pm, David R. Hassall WA5DJJ wrote:
Dear Al,
.............Another hint is to glue a 4-40 Nut to the crystal can of the 27MHz Crystal........?
Thanks for the suggestions! I have read about the nut on crystal solution. In another project, SoftRock Lite, you solder a ground wire to the crystal case. Now, that shows the case can take solder in small dabs. That leads me to think that maybe a small strip of copper could be soldered to the 27mHz crystal's case and become a more effective heat sink than gluing the nut.
I haven't looked too closely at the scope of the project, and maybe there's just not enough room for that type of solution.
On the PS question, would you say that anyone using a LM7805 type regulator (typically 1A capable) would experience the same issues as me on QRSS? I did try another '7805 PS board, but with no heat sinking of the IC, and got pretty much the same results. Another thought is to power the PA separately from a different PS as a way to lighten the load during TX intervals. But, barefoot the U3S draws relatively little power a 1A supply should be enough, IMO. Once the U3S is put into transmit on FSKCW it's drawing current continuously through the cycle and the frequency shift shouldn't cause that much of a load change on the PS. But, we're talking just a few Hertz, so limitations in the PS shouldn't be swept under the carpet.
Well we've still got time to play! Thanks again for your help and support of QRSS!!
73,
--Al
