SSB Tuner Connection.

[AnchorageGuy]

For the SSB knowledgeable folks like Bill, etc. here is my issue. With an Icom AT140 mounted where it needs to be, the copper strap that attaches to the tuner lug can not be run from the tuner directly to the bilge because of space constraints. The distance is about 10 feet. I can use wire or cable of limited size. So my question is, can the tuner be connected to the copper strap via a piece of wire or cable or is there an alternative way to connect the two?

[Viking Sailor]

Chuck,

Use as much stainless steel straping/tape as possible between the tuner and ground. Connect any gaps with stainless steel braid. The braid can be pull to thin it and pushed to re-spread it out. This will allow it to be run through tight spots.

A source of braid is the armored water hoses available at hardware stores. Just cut off the the ends of the hose, pull out the rubber tube, and flatten the braid.

Good luck,

Paul

[AnchorageGuy]

Paul, Thanks, there is a wire run that is already pretty full that the strapping needs to go through that is about 6 feet long and then the strap will be in the engine compartment and I can do whatever needs to be done. Total from the tuner to the engine compartment is 10 feet. The water hose might be a good alternative to get into the engine compartment. The question becomes whether I can find the water hose long enough since I have only seen short connection pieces.

[Viking Sailor]

Chuck,

If reasonable, you might want to find a path between the tuner and ground that doesn't use an existing wire run. The coupling to other circuits in the wire run could be problematic.

If there is a submerged thru-hull or rudder tube nearby you could try connecting to it and see how that works.

Paul

[btrayfors]

Chuck,

There are several ways to fashion an effective RF ground; you needn't necessarily think of running something into the bilge.

Not sure what your situation is, but it might be helpful to review my post on RF grounds in the marine environment...here: SSCA Discussion Board :: View topic - RF GROUNDS IN THE MARINE ENVIRONMENT

With more details/pix, I might be able to make more constructive suggestions.

Bill

[AnchorageGuy]

Bill, the new trawler will have the radio and tuner installed in the overhead of the interior steering station. The whip antenna will be mounted on the side of the cabin near the radio and tuner. The problem is the only way to get the ground strap to the water is through this wire run going from the electronics, etc. to the engine compartment and bilge. I will try to get some pictures and post them. Any suggestions are appreciated.

[btrayfors]

Chuck,

I don't know the MT34 very well, but I think in your situation I'd first think of alternatives which could work as well or better....like radials, or radial-like structures.

Some boats have aluminum toerails, or s/s rubrails. These can serve as very effective RF grounds. One boat I worked on recently...an 87-footer...had copper strips embedded in the overhead of the flying bridge.

About a year ago I made up a radial system for the marine bands from 6-conductor #12 wire; it has six different lengths of wire all contained in the same casing, so provides 1/4-wave radials for each of 6 marine bands.

Would it be possible to use any of these alternative schemes?

Also, you can do several things, not just one. Run copper strips and/or heavy cable to the nearest bronze thru-hull. AND, think of running radials or additional copper embedded in cabin top, underdeck, etc.

Bill

[AnchorageGuy]

OK, the pictures may not be great but hope they will help. The first pic is where the radio will be flush mounted with the tuner behind it. The second pic shows the VHF mic and behind that is a PVC pipe with wiring running done to the electrical panels and engine compartment. This is where the strapping needs to be run. I don't see any other alternative without major surgery to run the strap unless someone ahs another suggestion. Thanks.

[AnchorageGuy]

Originally Posted by btrayfors

Chuck,

I don't know the MT34 very well, but I think in your situation I'd first think of alternatives which could work as well or better....like radials, or radial-like structures.

Some boats have aluminum toerails, or s/s rubrails. These can serve as very effective RF grounds. One boat I worked on recently...an 87-footer...had copper strips embedded in the overhead of the flying bridge.

About a year ago I made up a radial system for the marine bands from 6-conductor #12 wire; it has six different lengths of wire all contained in the same casing, so provides 1/4-wave radials for each of 6 marine bands.

Would it be possible to use any of these alternative schemes?

Also, you can do several things, not just one. Run copper strips and/or heavy cable to the nearest bronze thru-hull. AND, think of running radials or additional copper embedded in cabin top, underdeck, etc.

Bill

Bill, I can easily get to the flybridge from the radio and tuner location. The difficult part is getting to the thru-hulls and there in lies the problem. That is the part that will need to go through the PVC wire run. No metal toe rails or SS rails on deck. There are SS stanchions with teak rails. The radio will be both SSB and Ham bands.

[captden]

Great thread I've been putting off finishing up my installation on my Icom 710 for a while because I thought you had to connect the rf ground to both the tuner and the reciever and they are tough to do as one is in the nav station (reciever) and the tuner is aft by the rigging. My question is, can I just ground the tuner to a thru hull or my stainless steel water tanks or do they both have to be tied together with the same ground strap.
captden

[Rick]

First attempt to locate the tuner down near the thru-hull fitting that you will use to make water contact.

If you cannot do that use 5 #16 (you could get away with #18Ga wire) Ga wires bundled together as closely as possible but insulated from each other. This will work better than strapping. Strip the wires at each end and connect them together making 5 (or more) parallel wires making a low effective inductance. This will also reduce the radiation from this "ground" wire into adjacent wires. The resulting combination will have a lower inductance than a strap and be easier to run.

[btrayfors]

Chuck,

Without being there on the boat, it's really hard to guess what might be the best approach. But, based on what you've said, and on the pix, and on what I know of Marine Trader construction (I'm more familiar with the 44), I think I'd investigate the possibility of (1) embedding a bunch of wide copper strips in the overhead, underneath the lining; and/or (2) doing something with the flybridge...maybe radials or a big loop of wire around it. Decorative s/s half-round strips, maybe?

Bill

[btrayfors]

captden,

A wide copper strap from the tuner to the nearest bronze thru-hull will work OK. Not the best RF ground, but functional.

B.

[btrayfors]

Chuck,

Yes, Rick's suggestion re: location of the tuner is a good one. Since you're going to be using a marine whip attached to the cabin side anyway, and since the base of this antenna won't be far above the deck, it might make sense to locate the tuner just under the deck where there's a straight shot to the nearest bronze thru-hull, and use GTO-15 wire from the tuner to the antenna base. That should work OK.

The 5-wire thing is an interesting twist, and I agree it would be better than ground-strap braid, but because the distance you mentioned is over 10' IMHO it probably wouldn't matter much (to be effective RF grounds should be kept very short wherever possible).

Lots of options :-))

Bill

[AnchorageGuy]

Great food for thought and much appreciated. Don't have the radio yet so not sure what kind of connection will be needed from the radio to the tuner. I did consider putting the tuner in the engine compartment if the cables to the radio won't be a bigger problem. At least I have some options to consider. Many thanks.