A radio can NEVER work without a ground?
hfeinstein at cox.net
Sat Aug 4 10:30:25 CDT 2007
No, Tom, your right on track.
Obviously the proposition is false by the two counter-examples I
provided. Early radio inventors thought the "ground return"
was a required element of all single wire communications systems, as
in any single wire electrical circuit, of which they thought radio
is an example.
(The single wire telegraph being another.)
Experiments by Hertz demonstrate transmission at a distance w/o a
required ground so, in theory, a ground return path might not be needed.
Today we know, as you rightly point out, that the ground plays no
role in ideal radio transmission. But the ground is still with us.
What should we think when told
to ground our receiver for "better" reception, and to ground our
transmitter to get rid of unwanted harmonics and improve range?
What magic is performed by this handy conductor at our feet?
Would the same mechanisms be in play between a transmitter and
receiver in deep space?
On Aug 3, 2007, at 5:52 PM, Tom Azlin, N4ZPT wrote:
> Hi Hal,
> Where did step one come from, i.e. the proposition?? An E-Field or
> H-Field antenna picks up the EM wave as it goes by, no ground needed.
> Thus your Sony works and the space probe works. And my coax fed
> dipole up in the trees!
> Or am I missing something??
> 73, tom n4zpt
> hal feinstein wrote:
>> Another of those glaringly obvious questions:
>> Proposition: In an idea system we know that radio reception can
>> only occur when a receiving apparatus conducts radio signals
>> from its antenna, through intermediate circuits, to ground.
>> Then: Removing either or both the antenna or ground renders the
>> receiver non-functional.
>> Conclusion: No matter in what form, all radio receivers (and
>> transmitters) must be grounded even if no attachment to the
>> "earth return"
>> is obvious. A ground must exist if the receiver functions.
>> Where is the ground?
>> Here I have a Sony 2010 tuned to a local station. It uses
>> batteries and has no attachment to the power distribution system
>> and thereby is not grounded through it. How does the radio
>> signal "return" to the transmitter?
>> A space probe in deep space sends a signal back to its Earth
>> controllers. Since the signal is received
>> we know there must be a "ground." Where is the "ground?"
>> --hal f
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