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-   -   Capacitors for SSB DC ground block (https://www.boatbanter.com/electronics/94155-capacitors-ssb-dc-ground-block.html)

joost April 26th 08 09:59 AM

Capacitors for SSB DC ground block
 
Hi all,

I´m planning to build a DC block for the SSB ground strap. The article
Marine Grounding Systems, http://www.sailmail.com/grounds.htm,
discusses how to make this and suggests the type of capacitor to use.
It´s the Type X7R Monolithic Ceramic capacitor, 0.15uF, 100 volt.
Unfortunately I can only obtain the 50 volt version in the place where
I am now (Whangarei, New Zealand). Are there any opinions on whether
this will also suffice? I´m transmitting using a 100W Icom 718 SSB
transceiver.

Joost Jager.

Larry April 26th 08 02:41 PM

Capacitors for SSB DC ground block
 
joost wrote in news:b1a9e798-612a-4ad9-96fc-
:

Hi all,

I´m planning to build a DC block for the SSB ground strap. The article
Marine Grounding Systems,
http://www.sailmail.com/grounds.htm,
discusses how to make this and suggests the type of capacitor to use.
It´s the Type X7R Monolithic Ceramic capacitor, 0.15uF, 100 volt.
Unfortunately I can only obtain the 50 volt version in the place where
I am now (Whangarei, New Zealand). Are there any opinions on whether
this will also suffice? I´m transmitting using a 100W Icom 718 SSB
transceiver.

Joost Jager.


Why do it all over again? The tuners, such as the Icom AT-140, already
have DC blocking capacitors built into them between the tuner and its RF
Ground terminal. Why put another one in series with the one already in the
tuner??


Glenn Ashmore April 27th 08 03:01 PM

Capacitors for SSB DC ground block
 
My AT-140 installation manual says to avoid connecting to the engine block
or the DC system ground. From everything I have read the tuner,
transceiver and TNC must be grounded to the same point to avoid ground
loops. The transceiver and TNC are connected to the system DC ground so if
you are going to take advantage of the keel or the engine for the RF ground
you need blocking caps.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Larry" wrote in message
...
joost wrote in news:b1a9e798-612a-4ad9-96fc-
:

Hi all,

I´m planning to build a DC block for the SSB ground strap. The article
Marine Grounding Systems,
http://www.sailmail.com/grounds.htm,
discusses how to make this and suggests the type of capacitor to use.
It´s the Type X7R Monolithic Ceramic capacitor, 0.15uF, 100 volt.
Unfortunately I can only obtain the 50 volt version in the place where
I am now (Whangarei, New Zealand). Are there any opinions on whether
this will also suffice? I´m transmitting using a 100W Icom 718 SSB
transceiver.

Joost Jager.


Why do it all over again? The tuners, such as the Icom AT-140, already
have DC blocking capacitors built into them between the tuner and its RF
Ground terminal. Why put another one in series with the one already in
the
tuner??




[email protected] April 28th 08 01:21 AM

Capacitors for SSB DC ground block
 

That is incorrect.

On Apr 26, 9:41*am, Larry wrote:
joost wrote in news:b1a9e798-612a-4ad9-96fc-
:

Why do it all over again? *The tuners, such as the Icom AT-140, already
have DC blocking capacitors built into them between the tuner and its RF
Ground terminal. *Why put another one in series with the one already in the
tuner??



joost April 28th 08 01:21 AM

Capacitors for SSB DC ground block
 
On 26 apr, 13:41, Larry wrote:
wrote in news:b1a9e798-612a-4ad9-96fc-
:

Hi all,


I´m planning to build a DC block for the SSB ground strap. The article
Marine Grounding Systems,http://www.sailmail.com/grounds.htm,
discusses how to make this and suggests the type of capacitor to use.
It´s the Type X7R Monolithic Ceramic capacitor, 0.15uF, 100 volt.
Unfortunately I can only obtain the 50 volt version in the place where
I am now (Whangarei, New Zealand). Are there any opinions on whether
this will also suffice? I´m transmitting using a 100W Icom 718 SSB
transceiver.


JoostJager.


Why do it all over again? The tuners, such as the Icom AT-140, already
have DC blocking capacitors built into them between the tuner and its RF
Ground terminal. Why put another one in series with the one already in the
tuner??


I have a AH-4 tuner and I´m sure that it has no blocking caps. I can
measure that a few milliamps of ground current are flowing through the
tuner, hull and engine block back to the battery when I switch on some
lights. This caused serious electrolysis problems on my prop and hull.

Larry April 28th 08 03:53 AM

Capacitors for SSB DC ground block
 
wrote in news:7ae7cb4c-2040-4de9-81ac-720bd9b0f719
@r66g2000hsg.googlegroups.com:


That is incorrect.

On Apr 26, 9:41*am, Larry wrote:
joost wrote in news:b1a9e798-612a-4ad9-96fc-
:

Why do it all over again? *The tuners, such as the Icom AT-140, already
have DC blocking capacitors built into them between the tuner and its RF
Ground terminal. *Why put another one in series with the one already in

the
tuner??




You win. You're right. How incredibly stupid that Icom doesn't INCLUDE
this important DC blocking capacitor into the marine design.

Ours is grounded to the engine block....just like the radio ground, the
NMEA ground, all the battery system grounds and everything else NOT tied to
the AC grounds, which go through the dock.

No WONDER nothing ever rotted and fell off! THEY'RE ALL PROTECTED BY ALL
THE ZINCS!



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