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The OTS units are not set up to interface to a bulkhead connector directly. The units Dan has are SB-2010 models which can be used as diver units or surface units. When used in diver mode, the transducer mounts directly to the unit. For surface mode, and the way we would use them in a sub, the transducer disconnects from the unit and is attached to a cable which has a male connector on one end to attach to the radio, and a matching female end that attaches to the transducer. The part # from the female end is the one I posted several posts back. When I get a few minutes, I’ll post all the part numbers and prices for both connectors, hoods, and pins. Once assembled, the hoods need to be filled with RTV to seal the cable end but the side that seals with the mating connector is sealed via an o-ring. With respect to the actual bulkhead connector, I believe the one Alec recommended is terminated with a pigtail on the inside, so virtually any type of 2 to 3 pin connector (with or without shielded grounding) could be used. A good cheap “Radio Shack” solution could be a ¼” phone plug and inline jack. Stereo plug if a shield is used. These are available in fully metal versions.
Al
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of vbra676539@aol.com
How is the OTS transducer made up to its bulkhead penetrator? Are the cables potted and rubber sealed, or do they have connectors on each end? If they use a connector, then we should probably buy them from the OEM and concentrate on receivers on each sub to match those requirements. It doesn't have to be complicated. K-boats typically have pipe nipples welded in here and there. Build an adapter with a female pipe thread in one end and the bulkhead penetrator receptacle thread in the other. Hull mods are then reduced to teflon tape and a crescent wrench, and there will be no ground issues, costs would stay low and everyone could toss the adapter into the parts bin when they are done. I am more concerned with clear comms in an at-sea condition. Vance -----Original
Message----- Sean, You bring up a good point and something I hadn't fully thought through. Youare correct that the cable shield would be better connected to the sub hullso that the penetrators would not need to be isolated. It's interesting to note that after looking at Dan Lance's OTS units, theyare using plain old RG-58 coaxial cable and while the cable itself isshielded, they are using the shield as just one of the signal lines to thetransducer. I did notice the transducer picked up a fair amount of 60 hzsignal from the power lines in his apartment. This obviously wouldn't existout on the water but may indicate a susceptibility to sub motor noise inaddition to possible ignition noise from the surface tender engine. Al -----Original Message-----From: owner-personal_submersibles@psubs.org[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Sean T.StevensonSent: Friday, December 18, 2009 8:22 PMTo: personal_submersibles@psubs.orgSubject: Re: [PSUBS-MAILIST] RFC - Standard Thru-Hull Electrical Connector Al, do you mean to suggest tying the shield to the safety / chassis ground, or to the electrical supply common? ABS etc. require that the entire DC system be ungrounded - that is, that the battery negative / supply common is not to be connected to the hull or equipment chassis. For maximum RF rejection in a shielded cable, that shield must be continuous through the shell of a metal connector. Tying the shield to the DC common would necessitate ensuring that all penetrators / connectors remain electrically isolated from the hull, lest they connect the DC common to the hull in violation of the Rules. Would it not be better practice to connect all cable shields, connector shells and equipment chassis together to form a contiguous RF shield while retaining isolation from the DC common (or, if the twisted pairs are individually shielded, tying the individual pair shields to DC common through a pin in the connector, but keeping the overall cable shield isolated and connected to the connector shell)? I'm not really an electrical guy - I'm genuinely curious. Sean Al Secor wrote:> > Alec,> > A couple of comments..> > # 5. Although Piezoelectric ceramic transducers do have polarity, > since we are feeding them with an AC signal then this is not an issue. > For noise considerations we may want to consider a shielded twisted > pair with the shield grounded to the sub's electrical ground.> ************************************************************************************************************************************************************************************************************************The personal submersibles mailing list complies with the US FederalCAN-SPAM Act of 2003. Your email address appears in our databasebecause either you, or someone you know, requested you receive messagesfrom our organization. If you want to be removed from this mailing list simply click on thelink below or send a blank email message to: removeme-personal_submersibles@psubs.org Removal of your email address from this mailing list occurs by anautomated process and should be complete within five minutes ofour server receiving your request. PSUBS.ORGPO Box 53 Weare, NH 03281 603-529-1100************************************************************************************************************************************************************************************************************************ No virus found in this incoming message.Checked by AVG - www.avg.com Version: 9.0.717 / Virus Database: 270.14.109/2567 - Release Date: 12/18/0914:38:00 ************************************************************************************************************************************************************************************************************************The personal submersibles mailing list complies with the US FederalCAN-SPAM Act of 2003. Your email address appears in our databasebecause either you, or someone you know, requested you receive messagesfrom our organization. If you want to be removed from this mailing list simply click on thelink below or send a blank email message to: removeme-personal_submersibles@psubs.org Removal of your email address from this mailing list occurs by anautomated process and should be complete within five minutes ofour server receiving your request. PSUBS.ORGPO Box 53 Weare, NH 03281 603-529-1100************************************************************************************************************************************************************************************************************************ No
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