[Hammarlund] Hammarlund power

[Kenneth G. Gordon]

On 6 Feb 2007 at 23:11, Mike Taylor wrote:

> Thanks for the replies. I must not be asking the question correctly. I
> understand that if I use a three conductor power cord, and connect the
> green wire to receiver chassis, then the receiver cabinet is connected
> to the earth. Is there something different in using a two wire power
> cord, and connecting the "G" terminal on the antenna input strip to a
> good earth ground (copper rod driven into the ground or metal water
> pipe connection)?

Take a look at the schematic diagram. That may help answer your 
question.

In many receivers, the "Gnd" or "G" terminal at the antenna input strip 
is NOT connected in any way to the chassis, but to one end of a coil 
that is part of the antenna input system.

If you connect the green wire of a three-wire system to the chassis, the 
chassis of the receiver is connected directly (more or less) to the 
POWERline ground, which is supposed to be connected directly to a 
ground rod.

You MAY use a ground rod connected to the "gnd" terminal at the 
antenna connector strip if you have an unbalanced (coax-fed) antenna, 
or you MAY connect that "Gnd" terminal to one of the two sides of a 
balanced antenna's feedline, like open-wire line, or 300 ohm twin-lead.

Usually in the older receivers, there were THREE connections on the 
antenna connection terminal strip: two for antenna, and one for ground. 
Then for an end-fed wire or for coax fed antennas, one of the two "ant" 
terminals was jumpered to the "gnd" terminal.

But in most cases, that "gnd" terminal or screw was not connected to 
the chassis.

In some cases it was, in which case, if you then connected that "gnd" 
terminal to a ground rod, your receiver would also be connected to it.

So, the correct answer to your first question would be, "It depends".

In any case, I would not rely on the "Gnd" terminal to carry the load of a 
properly connected green wire to the chassis.

In my case, I always use a three-wire cord and connect the green wire 
directly to the chassis...except for AC/DC sets, in which case, you have 
to do something totally different.

Ken Gordon W7EKB