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Forum Category: PT Boats of WWII
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Forum Name: PT Boats - General
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Topic: SO-A RADAR
http://www.ptboatforum.com/cgi-bin/MB2/netboardr.cgi?cid=101&fid=102&tid=2484



All
Good evening. I am currently make my radar mast. Looking through the new Squadron Higgins book I noticed in a few photos that the , don't lnow the real name, but I will call it the "oscillating drive shaft" for the radar is housed in a square "tube". I always thought this was actually round because of the rubber boot atop of the radar unit. My question: was this square tube ever removed abd the round shaft was exposed, or was this always square?
Thanks,
TED



Posted By: TED WALTHER | Posted on: Feb 9, 2012 - 2:39pm
Total Posts: 2932 | Joined: Oct 16, 2006 - 7:42am



I'm going to play devil's advocate and suggest that there is no drive shaft inside this object. I suggest that it is a cable conduit. One reason is that on most small boat radars, the drive motor is integral with the antenna mount. Another is that, if you look at SO3 masts, the object is shorter and comes out of a junction box midway up the mast. Sometimes it even has a bend in it.

What we need is a Raytheon manual for SO and SO3. Anyone work for Raytheon or know someone who does???

Al



Posted By: alross2 | Posted on: Feb 9, 2012 - 4:37pm
Total Posts: 920 | Joined: Oct 30, 2006 - 8:19pm



AL;
OK I will go along with conduit. That seems correct. I have only seen this set-up on PT's. Our units on the MK lll and MK lV PB's were cabin top mounted units, so we did not have a use for this. Learning something new everyday!
Take care,
TED



Posted By: TED WALTHER | Posted on: Feb 9, 2012 - 4:47pm
Total Posts: 2932 | Joined: Oct 16, 2006 - 7:42am



Arrrrrrgh, Ted. You gave in too easy[:-devil-:] I'm just posing this as food for thought at this point.

Al



Posted By: alross2 | Posted on: Feb 9, 2012 - 4:51pm
Total Posts: 920 | Joined: Oct 30, 2006 - 8:19pm



Poser? I think not my friend you are and will always be the guru!!!!!
Take care,
TED



Posted By: TED WALTHER | Posted on: Feb 9, 2012 - 6:19pm
Total Posts: 2932 | Joined: Oct 16, 2006 - 7:42am



Hi Ted and Dr Al,
You guys must be omniscient! We are working on installing our newly (on loan) radar mast from Don Shannon and PTBI onto the PT658. Frank Andruss helped us along with several others get the mast here from Mass. It has a bracket/shelf near the bottom for a big box and then up the middle is room for that rectangular cross section conduit,. I have always imagined the lower box was a big motor? and the conduit must contain a shaft to turn the antenna? This is for an SOA model (with a Dome on top) Look at this photo and tell me what you think? We are working on installation as we speak, so if you have any ideas I would sure appreciate it! I am trying to have the big box and conduit made next week.
Thanks Jerry
PT658 Portland OR.

Details visible on mast
[image]http://i130.photobucket.com/albums/p249/ptboats/Jerry%20Gilmartin/PT490GeneralMacwithflag.jpg[/image]

New mast in PT658 boat house
[image]http://i130.photobucket.com/albums/p249/ptboats/Jerry%20Gilmartin/Newradarmastonbench.jpg[/image]

New prop and arch for radar mast
[image]http://i130.photobucket.com/albums/p249/ptboats/Jerry%20Gilmartin/NewRadarmastbowandpropjustarrived.jpg[/image]



Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Feb 9, 2012 - 8:51pm
Total Posts: 1290 | Joined: Oct 8, 2006 - 11:16pm



Jerry,
What is it made of? Wood? Metal? Both?
Dave

David Waples

Posted By: David Waples | Posted on: Feb 10, 2012 - 4:38am
Total Posts: 1637 | Joined: Jan 2, 2007 - 9:55pm



While I am not a technician but based on my Navy experience, I believe that it is indeed rectangular and it is a waveguide which is needed with radars.
Simple definition: A waveguide is an electromagnetic feed line used in microwave communications, broadcasting, and radar installations. A waveguide consists of a rectangular or cylindrical metal tube or pipe. The electromagnetic field propagates lengthwise. Waveguides are most often used with horn antenna s and dish antennas.

It is hollow, and does not rotate.

For a more technical explanations:

[url]http://www.radartutorial.eu/03.linetheory/tl10.en.html[/url]

Also this:

[url]http://www.hnsa.org/doc/radar/part1.htm#pg14[/url]


Charlie

Posted By: 29navy | Posted on: Feb 10, 2012 - 5:58am
Total Posts: 535 | Joined: Dec 28, 2006 - 3:02pm



Thanks, Charlie. Germantown doesn't have an SO manual tucked away, do they???

Al



Posted By: alross2 | Posted on: Feb 10, 2012 - 6:23am
Total Posts: 920 | Joined: Oct 30, 2006 - 8:19pm



During the late 60's I was a Navy Electronics Technician specializing in Electronic Warfare but spent a lot of time working on radar and Charlie is exactly correct concerning the waveguides - they are very precisely designed to work with the specific wavelength of the radar which determines the size and dimensions of the waveguide itself - I have been looking for an SO manual for years but my belief is the big box is actually the receiver or radar unit itself - the antenna sends the signal down through the waveguide to the receiver where it is processed and then sent along to the radar repeater where it is viewed on a cathode ray tube (CRT) as everyone is familiar with from the movies - the signal between the receiver and the CRT is transmitted on coaxial cable similar to what is used with a television antenna. I also have one grainy picture of the inside of an SO antenna that I will send to David and he can post if he would be so kind. I also have several pictures and/or drawings on SO masts that I have collected over the years that everyone may have seen already but will also send them to Dave tonight for posting.
Jerry

Jerry Beasley

Posted By: Jerry Beasley | Posted on: Feb 10, 2012 - 8:02am
Total Posts: 89 | Joined: Jan 9, 2008 - 4:27pm



Just a side note: My dad served on a PT boat, (as a Quartermaster, not a radarman) and then years later spent a decade or so developing waveguide for telecommunications purposes at Bell Labs. Waveguide sounded pretty high tech to me at the time, it never would have occurred to me that he was first exposed to it during WWII.

Keith



Posted By: kgretter | Posted on: Feb 10, 2012 - 8:14am
Total Posts: | Joined: Unregistered



Guys,

I talk to Ron 15's Radar Tech often. I'll see what kind of info he can give you. Maybe he has an SO manual he could lend..................


Steve

Posted By: Nuge210 | Posted on: Feb 10, 2012 - 8:23am
Total Posts: 322 | Joined: Jun 4, 2008 - 7:50am



Most have probably seen this SO3 drawing from the Louisiana library site, of interest because it labels some of the components. It looks similar to the photo Jerry posted except for the resonance chamber and curved (waveguide?):
[url]http://www.pt103.com/images/ptpics/higgins/Higgins_SO3_Radar_Plan_FESO3_1_1944_Straightened.jpg[/url]

Did the resonance chamber amplify the signal?




Posted By: Jeff D | Posted on: Feb 10, 2012 - 8:53am
Total Posts: 2044 | Joined: Dec 21, 2006 - 1:30am



Here is a nice example: PT 305 RON 22 Bastia 1944. Notice position of BN antenna and IFF antenna.
take care,
TED
[image]http://i130.photobucket.com/albums/p249/ptboats/Ted%20Walther/PT305RON221944.jpg[/image]



Posted By: TED WALTHER | Posted on: Feb 10, 2012 - 9:27am
Total Posts: 2932 | Joined: Oct 16, 2006 - 7:42am



Hi David, Yes the radar mast is made of wood with metal attachments. The wood is all laminated plywood. It is amazingly lightweight for its size and we guessed the legs are basically hollow beams. I am truly amazed by the workmanship they put into the radar mast. I hope this is helpful. Jerry.

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Feb 10, 2012 - 11:06pm
Total Posts: 1290 | Joined: Oct 8, 2006 - 11:16pm



Here is what I received from Charlie Dewey, Ron 15's civilian radar tech.

"The antenna is in a fiberglass Raydome at top of A-frame wooden mast.
The long rectangular tube is waveguide.
The big aluminum box at the bottom contains the micro-wave RADAR electronics. Various power & control cables run from there to the operator's display position in the Radio/RADAR shack fwd of the bridge.

I'm sorry, but I don't have any manuals etc. They were all highly classified & turned in when I left.

You might try a web search. Raytheon archives maybe ? "

Steve

Posted By: Nuge210 | Posted on: Feb 12, 2012 - 7:23am
Total Posts: 322 | Joined: Jun 4, 2008 - 7:50am