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-   -   Why ground the transmitter? (https://www.radiobanter.com/antenna/85601-why-ground-transmitter.html)

Reg Edwards January 2nd 06 05:09 PM

Why ground the transmitter?
 
Transmitters, like any other 50/60 Hz AC power operated equipment,
should be grounded for safety reasons.

This is done automatically via the AC power cable regardless of what
floor level the transmitter is located.

If a balanced feedline is used to the antenna then no other grounding
is needed.

If the antenna is an endfed wire then, for good RF radiating
efficiency, there should be a low impedance connection between the
TUNER and ground. The transmitter can still be left to its own
devices.

If the transmitter and tuner are in the same box then the low
impedance ground connection and the AC power ground are in parallel
with each other. This results in an even lower impedance RF ground
connection.

On whatever floor the transmitter + tuner is located, to obtain a low
impedance ground, connect everything in sight together via the
shortest reasonably possible wires, including hot and cold metal water
pipes, the domestic plumbing system, central heating system, not
forgetting the incoming water and gas mains.

The more the merrier! But only 2 or 3 distributed wires can be very
effective.

Running a copper strip down an outside wall to a set of shallow buried
radial wires in your back yard will be useful provided the length of
the copper strip is NOT 1/4-wavelength at your favourite operating
frequency. A single ground rod is wasted time, money and labour.

But, in general, if you live several floors up in a block of flats, a
centre-fed dipole of random length, fed via a 450-ohm ladder-line,
plus a tuner plus ckoke-balun, will be the more convenient and RF
power-efficient option.

Any objections from the experts and Guru's?
----
Reg, G4FGQ.



[email protected] January 2nd 06 07:17 PM

Why ground the transmitter?
 
Any objections?

If there is no need for an RF ground, I think trying to
conjur one up is silly and just adds more problems.
IE: "virtual grounding"...Thats sillyness... :/

IE: ..
On whatever floor the transmitter + tuner is located, to obtain a low

impedance ground, connect everything in sight together via the
shortest reasonably possible wires, including hot and cold metal water
pipes, the domestic plumbing system, central heating system, not
forgetting the incoming water and gas mains.


Sounds like a good way to connect to a bunch of noise to me...
After all, ground is a noise source.
If the antenna is not fed directly from the shack, IE: end fed wire
from a shack tuner, I don't try to "rf" ground the shack. Being I
never feed directly from the shack, I never try to ground it.
I could be on the ground floor, or the 22nd, and I would not notice
any difference in operation. Also when mobile...Sure , I make sure
the ground under the antenna is very good. It's the rf ground. But..
I rarely bother grounding my rig itself. There is no real need.
Besides, it is grounded, when you consider the (-) power connection.
I know I'm a weirdo, but I think there are few cases where a ground
is required in radio operation. Overall, ground is either a bandaid,
or a
noise source, or a good place to lose useful rf due to excess
ground losses. The latter due to poor rf grounds under an antenna.
I think the farther one can stay away from grounds the better, overall.

I've never had much use for ground, except under vertical antennas, or
to safety ground high voltage gear like tube radios and amps.
MK


Bill Turner January 2nd 06 07:41 PM

Why ground the transmitter?
 

ORIGINAL MESSAGE:

On Mon, 2 Jan 2006 17:09:08 +0000 (UTC), "Reg Edwards"
wrote:

If the antenna is an endfed wire then, for good RF radiating
efficiency, there should be a low impedance connection between the
TUNER and ground.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

End fed wires should only be used for transmitting when people are
bleeding and the phone is out.

73, Bill W6WRT

Bill Turner January 2nd 06 07:44 PM

Why ground the transmitter?
 

ORIGINAL MESSAGE:

Previously posted:

On whatever floor the transmitter + tuner is located, to obtain a low

impedance ground, connect everything in sight together via the
shortest reasonably possible wires, including hot and cold metal water
pipes, the domestic plumbing system, central heating system, not
forgetting the incoming water and gas mains.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Yep, those things radiate reeeeeely good, don'tcha know.

Busted any pileups lately?

73, Bill W6WRT

'Doc January 2nd 06 10:23 PM

Why ground the transmitter?
 
MK,
Unfortunately, grounds are sometimes necessary (neighbor, TVI/RFI),
even with dipoles/loops. Wish it weren't, I'm lazy...
'Doc

Mike January 3rd 06 12:45 AM

Why ground the transmitter?
 
Why is that? I use them all the time with excellent results.
Mike


Bill Turner wrote:
ORIGINAL MESSAGE:
End fed wires should only be used for transmitting when people are
bleeding and the phone is out.

73, Bill W6WRT


Bill Turner January 3rd 06 04:30 AM

Why ground the transmitter?
 

ORIGINAL MESSAGE:

On Tue, 03 Jan 2006 00:45:45 GMT, Mike
wrote:

Why is that? I use them all the time with excellent results.
Mike



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Your results are "excellent' because you've never used anything
better. Put up a modest yagi and prepare to be amazed. Even a good
dipole will beat a longwire worked against ground.

73, Bill W6WRT

[email protected] January 3rd 06 06:17 AM

Why ground the transmitter?
 
Unfortunately, grounds are sometimes necessary (neighbor, TVI/RFI),
even with dipoles/loops. Wish it weren't, I'm lazy...
'Doc


Hummmm...Maybe, but I'm having a hard time of thinking
of the uses of a ground to cure said problems... Most
of those problems would seem to be better cured using chokes,
etc. If the problem is fundamental overload to their gear, any
grounding on your end won't cure that.
MK


Roy Lewallen January 3rd 06 07:19 AM

Why ground the transmitter?
 
wrote:
Unfortunately, grounds are sometimes necessary (neighbor, TVI/RFI),
even with dipoles/loops. Wish it weren't, I'm lazy...
'Doc



Hummmm...Maybe, but I'm having a hard time of thinking
of the uses of a ground to cure said problems... Most
of those problems would seem to be better cured using chokes,
etc. If the problem is fundamental overload to their gear, any
grounding on your end won't cure that.
MK


If you have an imbalance current trying to find its way to ground, it'll
take the path of least resistance (technically, impedance). If that path
is the mains wiring, you have a lot of potential for RFI. If you can
convince some of that current to go elsewhere by "grounding" your
station, you're likely to cut down the RFI. But a better solution is to
get those feedline currents balanced so you won't have any imbalance or
"ground" current to deal with in the first place. It brings the added
benefit of putting the power into your antenna to be radiated rather
than being radiated from the conductors carrying the imbalance current.

Roy Lewallen, W7EL

Reg Edwards January 3rd 06 08:32 AM

Why ground the transmitter?
 
Radiation from the feedline is usually the least of one's problems.

99 % of RFI is due to radiation from the very nearby antenna.

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