[TenTec] Station power supply??

[Bob McGraw - K4TAX]

Jims point is well taken.  This is one and the precice reason that I stress 
one must connect a ground wire from the radio ground terminal to the power 
supply ground terminal.   DO NOT rely on the power supply negative lead and 
associated connectors to be of adequale of low resistance to keep the radio 
at zero volt potential.

So to summarize, to connect the radio to the power supply requires three 
wires:  Positive, Negative, and Ground.

73
Bob, K4TAX


>
> Bonding -12VDC to the chassis causes a problem when powering a SSB rig 
> that SOUNDS like RFI, but is NOT RFI.  W8JI pointed out this problem to me 
> several years ago. Ohm's Law causes IR drop in both V+ and V- conductors 
> that varies with SSB modulation.  Nothing new. But when V- is bonded to 
> the chassis, and when audio accessories are running from that same supply, 
> the modulation of V- is added to the audio. That modulation SOUNDS like 
> SSB in an AM detector -- it SOUNDS like RFI.  But it's not.  You can hear 
> this modulation if you connect headphones between one end and the other of 
> the V- conductor of your power supply wiring.
>
> I have long advocated bonding chassis to chassis for all equipment in our 
> ham shacks to minimize problems with hum, buzz, and RFI. This practice 
> also reduces the above problem to the point where it is not audible. .
>
> 73, Jim K9YC
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