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Telamon wrote in message ...
In article , "DJB" wrote: Question to the group, Is it better to have a separate ground for you random wire short wave antenna (w/9:1 transformer) and a separate ground for your receiver (station ground) or can both use the same ground? If both were connected to the same ground, wouldn't that cause ground loop problems? Thank you in advance It prevents a ground loop problem to use isolated grounds. Huh???? This doesn't make sense to me. Using separate grounds is the fastest way to cause a ground loop. All grounds should always be tied together at a common point. It's in the NEC. And all gear should use it's own single wire to that single ground point. "star configuration" This assures no ground loops. It will help reduce noise from the AC powering your radio from being part of the ³measurement³ in this case the signal of the station you are trying to receive at the input to the radio from also seeing noise on the AC power system. How will grounding a radio reduce AC power noise? If you have AC noise, you need AC line filtering, not a ground. Or seems to me anyway...I haven't grounded any of my radios in years. I don't have AC noise problems, unless I pick up radiated line noise. No grounding will cure that. Creating a ground for the antenna that is isolated from the power ground through the ³transformer² will help reduce the noise floor on received signals. I don't see how. But even ignoring that, what you propose is a violation of NEC. And it's also a way to ensure severe lightning damage if that ever occurs due to the differences in ground potentials. If you built a balanced or complete antenna like a dipole the antenna ground would not help much at all. True. The transformer would still help to isolate the antenna circuit from the virtual RF ground to the AC system reducing the noise floor. This confuses me though...What virtual RF ground? Normally, the AC system should not be an issue if using a dipole. Best way to ensure a quiet dipole is to use good decoupling. IE: balun, chokes, etc to reduce noise ingress... Myself, and this is open to debate of course...I would use a single ground point. I would use a ground rod at the balun. And that ground would be bonded to the main house ground system to keep at the same potential. I probably would not bother grounding the radio, but if I did, I would use a single wire to the same ground outside the shack at the balun. There is no way this will cause a ground loop. And will reduce problems if lightning strikes. Remember the recent lightning post where all gear in the house was trashed? Thats what happens when you don't bond all grounds together to keep them at the same potential. Of course, I don't consider mine the last word, but I do have to respectably disagree with your separate grounding proposal...I would never do that myself. MK |
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