On Jul 11, 2008, at 6:44 AM, k5nwa wrote: > At 07:54 AM 7/11/2008, you wrote: >> However, I did notice a strange occurrence on >> the oscolloscope, with the SEC-1223Â keydown >> continuous, there was just a voltage drop. But >> with the W-30AM, there was oscillation between >> the dropped voltage and the full voltage on continuous keydown. > >> Will this oscillation cause my problems? I see >> it as TVI/RFI and am awaiting my XYL to return >> from work to get her assistance in more testing. Kind Rgds, Gwyn - >> G4FKH > > Oscillations are not good at all. You need a > better power supply or a lot of work on cleaning that one up. > > I keep mentioning that to test the power supply > you need a dynamic test not a steady state test > because how the power supply reacts to change can > be many times worse than the wiring drop, but it > seems that the people testing are bent on doing > static test which are rather useless in the long > run. Forget DVM's they are too slow to see what > is going on you need an oscilloscope. > > You can take a horse to water but .....
It is all part of the testing process. Remember, the power feed system has it own *impedance*. That means resistance AND reactance. The static test is measuring the *resistance* of the power supply and power wiring. Certainly one can tackle those problems first, mostly just use fatter wire. Certainly the measurements at the output of the power supply suggest that the supply is very "stiff" and doesn't change much from no-load to full-load. But we aren't measuring the reactive portion. The biggest problem is inductance in the wire. First step to combat that is the bring the wires as close as possible in parallel (or twist them) in order to cancel their mutual inductance. That will help stiffen things up to a dynamic signal. The other thing that will help is to put a lot of energy storage (capacitance) right at the load (radio) in order to cancel out the inductive component of the wire. So yeah Cecil, a scope will let us see what is going on right at the radio. OTOH, I am sure that Flex could tell us if there is sufficient bypass inside the radio itself thus solving the problem. -- 73 de Brian, WB6RQN Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
