Re: [Amel Yacht Owners] Re: Icom M802 and AT140 tuner grounding

Herbert Lackner

If you want to be on the safe side you can put 10 small ceramic capacitors with 3900pF (2500V) each, solded together in parallel (will give 39nF(2500 V) with little Skin Effect) between the tuner ground (ssb ground) and the boat ground.  This will prevent any DC current (and will prevent electrolysis) but will give a solid HF AC connection.  


Am 07.06.2014 um 00:49 schrieb "'Mark Erdos' mcerdos@... [amelyachtowners]" <amelyachtowners@...>:


Alan is 100% correct. I spent hours (okay ~ days ~ or, perhaps weeks) researching this. The 802 cable that connects the 802 to the AT has a ground wire and should be connected to both the 802 and to the ground on the AT which in turn is connected to the copper strap in the lazarette. There is no connection to the ships common ground (yellow and green wiring system) .


I installed an isolated 24-12 power supply. Although this has a ground connection available, I was told not to connect it. Only the battery cables are connected to the isolated 24-12 power supply.


Hope this helps.


Best regards,




Sailing Yacht Cream Puff




From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Friday, June 06, 2014 6:37 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Icom M802 and AT140 tuner grounding



Amel say don't  connect the SSB ground to the ships earth...


The 802 ground should be connected to the tuner ground and that connected to the copper strap in the lazarette only.


If you don't have an isolated 24 - 12v supply for the SSB, you need some way of isolating the negative supply of the SSB when not in least for the 710, where the negative power line in the SSB is connected internally to the earth.


I posted a simple way of doing this that completely isolates the SSB when you turn the breaker off.


If you don't do this the negative supply will have a low current connection to ships ground through the seawater.


Hope this helps



SV Elyse SM437


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