ssb grounding

[Steve (another one)]

I have an icom M700 with an AT-120 antenna tuner.
I understand the importance of good grounding for the AT-120, but do I
need to be as paranoid about grounding the M700 itself ?

Thanks

 

[Jack Painter]

I have an icom M700 with an AT-120 antenna tuner.
I understand the importance of good grounding for the AT-120, but do I
need to be as paranoid about grounding the M700 itself ?

Thanks

Steve, here is a good description of the best way to achieve galvanic
isolation of RF ground. The transmitter may use coupling to achieve RF
ground, but if that turns out to harm performance there are options as
discussed in this report:

http://www.sailmail.com/grounds.htm

Best,

Jack Painter
Virginia Beach, VA

 

[Steve (another one)]

I believe the question was about connecting the radio as well as
the tuner to the counterpoise. The answer is ... yes! As simple as
that.

Doug, k3qt
s/v Callista

Thanks for this, sorry if I wasn't clear.

The boat is steel so a short copper strap from the tuner to the hull is
easy. However, it's harder to do the same to the M700 neatly. Everybody
stresses the impoprtance of a wide strap to the tuner but rarely mention
the radio itself, those that do say it is 'good practice' to connect it
to the same ground. I was wondering if I could get away with a lighter
wire or thin self-adhesive copper tape for this.

Steve

 

[Gary Schafer]

Thanks for this, sorry if I wasn't clear.

The boat is steel so a short copper strap from the tuner to the hull is
easy. However, it's harder to do the same to the M700 neatly. Everybody
stresses the impoprtance of a wide strap to the tuner but rarely mention
the radio itself, those that do say it is 'good practice' to connect it
to the same ground. I was wondering if I could get away with a lighter
wire or thin self-adhesive copper tape for this.

Steve

Steve,

The radio itself doesn't need any ground connection in order to
perform. The main reason for connecting it to a ground is to eliminate
stray RF from getting back into the radio and causing problems.

If an installation performs ok with no ill effects without a ground on
the radio then not to worry.

In your case with a steel hull I would bet that you won't have any
problems. In most cases stray RF comes from having poor ground systems
for the tuner and allowing RF to be carried on long ground leads and
get coupled to dc leads etc. With a steel hull you have about the best
ground system that can be had on a boat.

The only problem that may arise is if your antenna runs close to the
radio itself or the dc power leads to the radio and RF is picked up by
them and gets into the radio.

It never hurts to have the radio grounded well though in case of
lightning coming to it via the coax from the tuner.

Regards
Gary

 

[Jack Painter]

"Steve (another one

Thanks for this, sorry if I wasn't clear.

The boat is steel so a short copper strap from the tuner to the hull is
easy. However, it's harder to do the same to the M700 neatly. Everybody
stresses the impoprtance of a wide strap to the tuner but rarely mention
the radio itself, those that do say it is 'good practice' to connect it
to the same ground. I was wondering if I could get away with a lighter
wire or thin self-adhesive copper tape for this.

Steve

Steve,

SSB radio to Tuner by ground strap _is_ the Radio's RF _and_ lightning
ground, as long as the Tuner has a good connection to sea-ground. For RF and
lightning protection, the copper connection you make between radio and tuner
is a bond, and the tuner is the connection with ground. Copper tape if 26ga
and 1" wide or better would be ideal for both RF and lightning bond
purposes. If the copper flashing is impractical for you, a soft braid
connection is also acceptable, but it should have as much surface area as
possible.

Best regards,

Jack Painter
Virginia Beach, Va

 

[Gordon Wedman]

On one of the Icom websites they have a 7 page PDF document specifically
addressing antenna grounding and they show the radio chassis grounded to the
"boat ground" (same as tuner) via copper foil. They don't explain the
reason but I believe they say it is important for performance.