Re: Matching transformer for PL-380


You're absolutely right, Rick. The best results I've achieved with the Quantum loop + PL-380 combo is when the Quantum is inductively coupled to the 7.5" loopstick on the modified PL-380, by means of the Quantum coupler. This works excellent.


Vardo isl. Arctic Norway 

---In ultralightdx@..., <n3ikq@...> wrote:

I'm not sure I understand exactly what you are doing but be VERY careful if you are connecting an external signal directly to the solder pads where the loop wires go. Go to Silicone Labs website and download the documentation for the Silicon Labs si4734 chip. You will notice that the loopstick forms a resonant circuit with varicaps embedded in the chip. To tune the radio the DSP changes the capacitor value effectively resonating the tank circuit to the desired frequency. In other words, the radio has its own internal tuned loop circuit. Attaching any high level signal in place of a loopstick seems dangerous. Additionally, there are many ESD warnings to the possibility of zapping the chip at the antenna input unless an external capacitor is used for protection when bringing in external signals. Indirectly coupling a signal into the original or supercharged loopstick seems to be the best and safest way as far as I can tell. Rick

---In ultralightdx@..., <hans.ostnell@...> wrote:


Anyone who could suggest a matching transformer to use when connecting the 50 Ohm output from my Quantum QX-loop directly to the PL-380?

What I'm doing now is to switch between the 7.5" loopstick and the QX-loop. The QX works pretty good together with the 380, actually, but I can see that I'm not taking full advantage of the QX sensibililty (i.e I loose gain from the loop when connecting it diretly to the ferrite input on the PL-380). This is most likely due to the impedance mismatch between the QX output and the ferrite input on the 380.

Yes, It works fine tocouple the QX inductive via the 7.5" loopstick, but I would like to experiment a bit with disconnecting the 7.5" loopstick from the system.


Vardo, Arctic Norway

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