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 Return to top of page · Post #: 16 · Written at 2:24:38 PM on 10 March 2017.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2371

Yeah, life was cheap in those days.


 
 Return to top of page · Post #: 17 · Written at 7:05:59 PM on 11 March 2017.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

Yes I will do that. It is quite dangerous.
Jimb.


 
 Return to top of page · Post #: 18 · Written at 5:36:05 PM on 14 March 2017.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

I have eliminated it. and I had already fitted a 3 core flex and grounded it . It now has a standard antenna wire.
Jimb.


 
 Return to top of page · Post #: 19 · Written at 9:47:59 PM on 14 March 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

Methinks a whole lot safer that way. Might even work better?

Marc


 
 Return to top of page · Post #: 20 · Written at 8:37:03 PM on 16 March 2017.
JamieLee's Gravatar
 Location: Clare, SA
 Member since 27 March 2016
 Member #: 1894
 Postcount: 510

I know this may be a silly question, but why would using the mains as an aerial be dangerous if properly isolated with an appropriate capacitor/ capacitors, and the chassis earthed? Given that there is lethal voltage present in many parts of a radio and generally with the chassis inside the case and the back on, one would presume that everything would be ok and that with one less wire coming out of the set, two less with an earthed 3 ply mains cord, everything would be internal and insulated?


 
 Return to top of page · Post #: 21 · Written at 8:50:20 PM on 16 March 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6687

Quite apart from the safety aspect, the mains are full of electrical noise particularly as AM goes and particularly these days.

So not a good idea at all.


 
 Return to top of page · Post #: 22 · Written at 10:04:02 PM on 16 March 2017.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2015

Yeah that's the main problem, it can carry all kinds of rubbish these days.

As an aside, I did try on one radio (as an experiment) using the earth wire (in the mains cord) as an aerial instead of its usual function... it does actually work. I wouldn't advise using it on other people's radios though. It might also cause a leakage-type circuit breaker to trip.


 
 Return to top of page · Post #: 23 · Written at 12:06:48 PM on 17 March 2017.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7303

What we need to assume is that most houses in Australia do not have RCD protection, because that is actually the case. That said, if an open circuit earth fault in an electrical installation is present and a fault also develops in an appliance, it will make all parts of the earthing system live.

With that in mind I don't recommend experimenting in this manner. There's too many unknowns...


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 24 · Written at 7:08:19 PM on 17 March 2017.
JamieLee's Gravatar
 Location: Clare, SA
 Member since 27 March 2016
 Member #: 1894
 Postcount: 510

Hmmn.. All parts of the earthing system live? That sounds rather scary!

I actually didn't think of that one, but yes, that's exactly what would happen and Murphy's law would make damn sure!

Risk minimisation is always best practice.

Good explanation. Thank you!


 
 Return to top of page · Post #: 25 · Written at 9:39:52 PM on 18 March 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

One thing from the regulations to consider when repairing. It actually states that if a metal part can become live, then it should be grounded.

Whilst the old transformers were built to a standard rendering them virtually as good as "double insulation"; By grounding the metal chassis on a transformer set, you virtually eliminate any chance of the chassis ever becoming alive.

What should be looked out for, are those line caps as the Americans used them a lot & I have a 1930's US radio here with them.

Some mains transformers are shielded and they bleed charge to the chassis. I have measured that at 185V on one (high impedance meter) that does not mean the transformer is defective (that one wasn't -- it got insulation tested). Grounding the chassis (naturally) gets rid of that charge.


 
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