[PSUBS-MAILIST] OTS

Mon Oct 26 14:00:18 EDT 2020

Hi Alan
Thanks for the video,. This is exactly what I was looking for. Did you use
these and do you have a source for purchasing them? I love the fact that
there is no soldering! David, check out this fitting and video.
Let me know.
Rick

On Sat, Oct 24, 2020 at 8:36 PM Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Rick,
> what about using these coaxial plugs, they look easy to attach to.
> https://m.youtube.com/watch?v=6BqpkqVp7-4
> Also you could experiment with soldering a scrap piece of coaxial & see if
> you melt the plastic insulation.
> Alan
>
>
> On 25/10/2020, at 7:03 PM, Rick Patton via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Thanks for the pictures David. I wish there was a fitting out there that
> you could push both ends into and tighten each end but there are none that
> I know of. Sean, I am concerned that when you peel the outer braided cable
> back on each end and solder them that the heat of the solder will melt the
> white plastic liner that separates the two.
> Rick
>
> On Sat, Oct 24, 2020 at 6:37 PM Sean T. Stevenson via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>> David, with coax, it's better if you loosen and pull the shield braid
>> back over the jacket all around on both sides, then cut the core wires a
>> bit shorter. Solder the cores together and insulate, then pull the braid
>> back into position with full 360° coverage, and twist it into the braid
>> from the other side - cutting the cores shorter should have given you a bit
>> of overlap to work with. Solder the braid all around and then heat shrink
>> the works.
>>
>> Sean
>> -------- Original Message --------
>> On Oct. 24, 2020, 22:09, David Colombo via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>>
>> Rick, I am cutting the ots comms wire as well to shorten its lenght for
>> the yellow sub, and to get it thru the blue globe fittings. Attached are
>> photos of the shield which is a braided multi strand wire and the interior
>> wire which is also multi strand.  I am assuming that when i rejoin the two
>> pieces there might be a small gap in which the sheilded braid may not
>> completely cover the inner core.  Its kinda like a chinese finger braid
>> that tightens when pulled on the ends. Does anyone have any concerns about
>> the surrounding sheild braid not completely covering the inner core?
>> Since the cable is 50ft long, I have lots of lenght to play with.
>> David
>>
>>
>> On Sat, Oct 24, 2020, 5:51 PM Rick Patton via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>>> Yeah I have the surface head set system so should be fine. I had to cut
>>> the wire though to pass it threw the hull penitraitor so I hope it will be
>>> easy to re connect and not have any shielding leaks from any other stuff
>>> running.
>>>
>>> On Sat, Oct 24, 2020 at 10:54 AM Sean T. Stevenson via
>>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>
>>>> I think the boom mics on the surface headsets are pretty forgiving. The
>>>> issue with the diver mics is that they are of a noise canceling design. In
>>>> an effort to filter out regulator hiss and bubble noise, there are
>>>> diaphragms on both sides of the mic, and the transmitted signal is actually
>>>> the differential between the two, which is best when the mic is right in
>>>> front of the diver's mouth. A lot of divers find this position a bit
>>>> invasive and incorrectly push it away further into the mask cavity, so then
>>>> the mic is exposed to similar signals on both sides and becomes less
>>>> intelligible.
>>>>
>>>> Not an issue for the surface hand mics or headsets.
>>>>
>>>> Good idea with the transducer mounting. High and omnidirectional is
>>>> ideal, so you avoid the shadowing. Actually, this is one area where OTS has
>>>> a deficiency in comparison to one of its competitors, at least with the
>>>> diver units. The SSB-2010 needs to be mounted on a waist belt, or on a tank
>>>> cam band, and there's really no practical mounting position for that unit
>>>> that leaves the transducer in an optimal position. Even the low powered
>>>> Buddy Phone units that they sell for recreational divers are mounted on the
>>>> side of the head, and exhibit shadowing in the cross body direction. In
>>>> contrast, Divelink makes their diver worn units with transducers that sit
>>>> on top of the head, attached to the upper strap of the face mask. I'm still
>>>> inclined to buy OTS though. On a sub of course, you can mount your
>>>> transducer anywhere you like.
>>>>
>>>> Sean
>>>>
>>>>
>>>> -------- Original Message --------
>>>> On Oct. 24, 2020, 14:33, Rick Patton via Personal_Submersibles <
>>>> personal_submersibles at psubs.org> wrote:
>>>>
>>>>
>>>> Thanks Guys
>>>>
>>>> In my case, the surface boat will not have the need to be underweight,
>>>> I will descend from the surface boat and it will just stay put except for
>>>> moving with the current. I won't have the thermoclines here in Hawaii that
>>>> most of you have but there are some of course. I will be using a headset
>>>> with boom mike so it will be almost touching my lips and I mounted the
>>>> transducer on the top of my hatch to minimize any ghosting on my end. I
>>>> agree Jon that it would be nice to have a topic on that. I would like to
>>>> put a face with all the guys here so where and when will be the next
>>>> convention? Oh yeah, the bloody coronavirus.Just got my trailer done enough
>>>> to get it weighed and a VIN number assigned to it so am stoked!
>>>> Rick
>>>>
>>>> On Sat, Oct 24, 2020 at 9:26 AM Jon Wallace via Personal_Submersibles <
>>>> personal_submersibles at psubs.org> wrote:
>>>>
>>>>> My recollection from Lake Tahoe was that comms were good when surface
>>>>> boat was somewhere in the vicinity OVER the submarine.  We didn't have to
>>>>> be directly overhead, just not too far away.  When David piloted R-300 he
>>>>> ended up a good 600-800 feet away from us laterally when comms became
>>>>> difficult.  Water column varied 60-100 feet (I think) in that area.  Comms
>>>>> ended when our propeller cut the transducer cable (whoops), ALWAYS pull up
>>>>> the transducer when surface boat is underway, even at slow speeds.  I'm
>>>>> just going to throw out a rule of thumb that has no emperical data to back
>>>>> it up, keep within the same distance laterally as the submarine is in
>>>>> depth.  If the sub is 100 feet deep, stay within a 100 foot radius of it.
>>>>> If it's at 1000 feet depth, stay within 1000 foot radius of it.  I think
>>>>> you could actually probably get away with a radius 4x depth and be ok, but
>>>>> keeping it 1-to-1 isn't a bad plan.
>>>>>
>>>>> Sean is correct that water conditions matter as well as fresh vs
>>>>> salt.  Even so, we should spend some time at our next "meet" to do some
>>>>> comm testing and publish the results on the web site just so we have some
>>>>> reference.
>>>>>
>>>>> Notwithstanding the timber sound aesthetics Sean mentioned, comm
>>>>> quality between surface and R-300 was loud and clear when within the
>>>>> parameters I mentioned above.  Cliff and David may have their own
>>>>> perceptions since they both manned the comms at some point during that
>>>>> weekend.
>>>>>
>>>>> Jon
>>>>>
>>>>>
>>>>>
>>>>> On Saturday, October 24, 2020, 03:01:32 PM EDT, Sean T. Stevenson via
>>>>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>>
>>>>>
>>>>> Rick, ultrasound behaves quite a bit different than does radio as far
>>>>> as the attenuation relationship to distance. Things like shadowing, (where
>>>>> a diver's body / equipment or the hull or superstructure of your sub gets
>>>>> in between the direct line of sight between transducers) will have a much
>>>>> more profound affect on transmission effectiveness than distance alone.
>>>>> Similarly, thermoclines and haloclines can act as "surfaces" that refract
>>>>> or reflect the ultrasonic transmission, so it is important for the surface
>>>>> crew to lower their transducer into the same operating layer as the diver /
>>>>> sub. As a diver, I always report the presence and depth of any thermocline
>>>>> encountered on descent to the surface support for this reason. Also, the
>>>>> surface transducer needs to be suspended in the water column and not
>>>>> bottomed or lost in surface sea clutter, and the transducer needs to be
>>>>> weighted and boat speed limited so that it doesn't trail behind at an angle
>>>>> which is ineffective for transmission.
>>>>>
>>>>> The rating in the published specifications for the OTS SSB-2010 (a 5
>>>>> Watt unit) is greater than 1000 meters in a calm sea, and ~200 meters in
>>>>> sea state 6 (Beaufort), but I presume that these are ideal scenarios
>>>>> whereby the surface and dived transducers are suspended at the same depth,
>>>>> in the same (vertical) orientation, with clear line of sight and no
>>>>> interfering reflections, and also with no squelch applied. Real-world
>>>>> conditions are obviously somewhat different, and the environment can
>>>>> actually be somewhat noisy at typical channel frequencies, requiring the
>>>>> application of some squelch and the consequent loss of range.
>>>>>
>>>>> Rated frequency response is ~300 Hz to ~3000 Hz, which covers most of
>>>>> the vocal range, but will not reproduce true timbre of voice. It is fine
>>>>> for intelligible speech, but not for e.g. music.
>>>>>
>>>>> I have used this unit as a diver only, so my impression may be also
>>>>> due to the influence of the earphone / microphone assembly in my mask.
>>>>> Choice of mask makes a difference (shape and size of gas cavity), as does
>>>>> proximity to the mic. You need to be almost kissing those OTS diver mics to
>>>>> get decent sound. That said, my experience with the SSB-2010 was decent,
>>>>> but that was in the context of a dive team separated by a few meters at
>>>>> most, and at relatively shallow depths (limited distance from surface unit)
>>>>> where helium based breathing gas was not required.
>>>>>
>>>>> I can't speak to long range effectiveness, other than at Flathead last
>>>>> year I was surface support for Cliff in the R-300. He was using a SSB-2010,
>>>>> but the surface unit we had was something different - one of the surface
>>>>> specific boxes, and I don't recall the model (Cliff?). There were times at
>>>>> which we lost him and had to reposition the boat to reacquire him, and
>>>>> others where we could hear him but he couldn't hear us, but I can't speak
>>>>> to the exact ranges, depths or boat speeds that caused those issues. It was
>>>>> never such a sustained loss of comms that the dive had to be called. Likely
>>>>> the result of relative orientation or depth, or shadowing of the
>>>>> transducers.
>>>>>
>>>>> Sean
>>>>>
>>>>>
>>>>>
>>>>> -------- Original Message --------
>>>>> On Oct. 24, 2020, 12:10, Rick Patton via Personal_Submersibles <
>>>>> personal_submersibles at psubs.org> wrote:
>>>>>
>>>>>
>>>>> wanted to hear from those who have and have used the OTS comms system.
>>>>> I was wondering how you liked the system and what your max clear
>>>>> audible range was.
>>>>> Thanks
>>>>> Rick
>>>>>
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