Vu meter, RF probe, GDO queries

I have just tried haha. It seems to work when I loop 1 turn over the GDO coil. Later, I will proceed with the adjustment.



73s

Hi,
any microammeter between 50 and 500 uA will usually do in RF indicators (GDOs, RF probes, SWR meters etc.) If you need to know its sensitivity exactly, simply put it in series with a multimeter set to the lowest current range and a big variable resistor, regulate the current to the maximum deviation and read its value. Be careful not to overload the meter, it can be destroyed easily by overcurrent.
I expect the BPF can be tuned using a RF probe or a GDO switched as an absorbing meter. Harry´s GDO-2 seems not to have this possibility, but I may be wrong.

BR from Ivan

Hi again. I have been playing with radio on and off for sometime now yet cant still understand RF. In an attempt to reboot this interest, I started to build the easybitx kit. The parts are mounted already except for the final transistor.

Now comes adjustment. I already have the gdo2 although the battery has drained already. I also want to build an RF probe using a salvaged meter. First question is, how do I know if this is a 50 or 100ua meter? Second, can I peak the bpf coil using gdo or should still build the rf probe?

Thanks and 73s