Help me ID a transducer please

[Luna Sea]

Hi,<br /><br />I bought my Grady last year without a fishfinder, guy I bought it from said previous owner removed the fishfinder, and replaced it with shoot through hull depth gage that hardly ever works. So I've been shopping for fishfinders, and came up with the bright idea that if someone could ID the bronze through hull transducer, I'll save about $180 and some labor!<br /><br />The radar and GPS are Si-Tex, so I'm thinking maybe it's a Si-Tex. If not, I think only others 8 or so years ago would be Furuno or Lowrance? <br /><br />The 8 pin plug is 1/2 inch in diameter with 7 pins in a clockwise location and one pin in the middle. Looks like one hole may not have a pin in it. And there's a little half moon locator up top. <br /><br />Rubber OD is .825 and cable diameter is .25. Here's a picture, please compare for me, fellow fishfinder owners.<br /><br />Thanks in advance<br />

 

[Luna Sea]

Re: Help me ID a transducer please

The transducer itself is 2 5/8 wide, 4 1/4 long and 1 1/8 thick, with one pointy end. The threads measure .825, probably a straight pipe and the nut is 1.03, probably for a 1 1/16 wrench. Here's a picture from inside the hull....<br /><br />

 

[Luna Sea]

Re: Help me ID a transducer please

Ok I found out some more info. If anyone wants to bother clicking on this link, and then click on "TD DRAWINGS", you'll find this on page 17. So I should be happy, but......<br /><br />I just got off the phone with Si-Tex, this identical configuration could be the 120 OR the 200 kilohertz! I asked the guy if I could test it myself and he said no, and if I buy a 120 KHZ machine I could void the warranty and/or do damage if I hook up the wrong transducer. You would think the pin missing at the 3 o'clock location on one would be like at the 9 o'clock location on the other. He said I may see some white paintlike markings on the cable down by the transducer, but a black cable that's been in the bilge for 8 years, it's doubtful.<br /><br />So I'm thinking gamblle here, a 200 KHZ transducer would be for shallow water right? And the 50 is for deep right? I'm gonna guess this is a 120 cause the guy was a tunafisherman, and the 200 would not be used offshore right? <br /><br />I'd like to pick up a Profish II 120khz and leave my transducer/fairing block setup alone! <br /><br />Whaddy'all think?????<br /><br />Thanks<br /><br /> Si-Tex Transducers

 

[18rabbit]

Re: Help me ID a transducer please

This critter looks remarkably like the one on page 17 of the Si-Tex diagrams. If it is, it is not an Airmar transducer, it is a RadarSonic. I think Boatist might use their product.<br /><br /> http://www.radarsonics.com/Model_201.htm <br /><br />I looked in the Airmar transducer cross reference guide and no Si-Tex instruments are listed. This makes me think you have a RadarSonic. I looked at RaradSonic’s spec sheet and there a 200khx, 160khz and 120khz with similar resistance. Depending on the matched resistance of the ff head, you could have anyone of those three frequencies. Also note in the spec it is possible to mis-match resistance within any of those frequencies, too.<br /><br />EDIT: It might be best to call Si-Tex support and ask what models of Si-Tex ff’s use the RadarSonic model 201A (or equivalent) 8 or 9 years ago, and what the transmit/receive impedance was/is for those ff heads. Alternately, you might get RadarSonic’s support to tell you what transducers they sold to Si-Tex 8 or 9 years ago that is equivalent to their model 201A and what the impedance was for those units.<br /><br />Also, if Si-Tex did not make a 300 watt ff unit it narrows the probability of what transducer you have. Considering tuna fishing, I’m thinking it was a 600 watt Si-Tex ff. If the difference is either 200khz or 120khz, the impedance would have to be 300-320 ohms. If so, you will need a 600 watt (or less) ff with that impedance.<br /><br />Please let us know what you find out. It looks like that is a pretty good little transducer and if it will work with a ff head you are comfortable with, it would be nice since it is already in place.

 

[Luna Sea]

Re: Help me ID a transducer please

18rabbit,<br />Thanks for the reply. I believe it IS the one from page 17 of the Si-Tex diagrams. But it sounds like you’re saying RadarSonics may make transducers for Si-Tex? Either way, I talked to the guy at Si-Tex yesterday, and unless I can find some true ID (paint markings) on the cable, he said to send it to them and they’ll tell me the frequency, for $30, plus shipping 2 ways, plus I’ll have to rip it out of the boat. Really didn’t want to break it away from the fairing blocks, my luck it’s probably gooped in with 5200 which could mean new fairing blocks and……..<br /><br />They said they have “special test equipment”, I work for a company that builds medical equipment, plenty of electrical engineers, oscilloscopes, ect. Anyone know how I can test whether it’s a 120 or a 200 khz? Without removing it? <br /><br />The guy that rigged the boat for tuna, and I can’t find him listed anywhere, put in the Si-Tex T-150 radar and the Si-Tex GPS-9D DGPS Navigator. So I believe there was a decent fish finder in there as well, sure would like to use this transducer……..<br /><br />Thanks again

 

[Luna Sea]

Re: Help me ID a transducer please

18rabbit (again)<br /><br />I guess you know your transducers huh? I had previously emailed Airmar the same info and they just wrote back that it is probably a Radarsonics. They suggested I find a local boat electronics tech that may have one of these in his box.....<br /><br /> Transducer Tester <br /><br />On a sidenote though, Airmar seems to list Si-Tex equipment as "Koden", which I believe is the mother company. I saw Profish II and III in the Koden area of the site.<br /><br />Something tells me I may be better off just getting a new transducer when I get a new unit. Seems a waste though, maybe I'll remove it and bring it to the local marine electrinics place to test, and maybe they'll give me a credit for the test.....