Homebuilt ROVs Forum

Has anyone ever got a actual price for a comercial tether? Or know of a site that will respond to a one off hobbyest? I realize that they are going to be expensive. But with the work(and money) I've got into my rov I don't think a homemade tether is going to do it justice. It's built to withstand pressure down to 450'
Thanks for any info you can share on the topic

Check out http://www.outlandtech.com/ I've talked to them in the past but never bought anything. Their tethers can be found on this page http://www.outlandtech.com/cables.php if I remember correctly the prices were around 3-5 per foot.

-Steve

This a quote I got last year.


Hi Ken,

Thank you again for your enquiry, we are pleased to offer as follows:

Cable: 4 x 2 x 24AWG F/UTP CAT6 CW FWNB

Cable 4 x 2 x 24AWG F/UTP CAT6 with cross web, foil screen and stranded conductors
Foamed polyolefine sheath
Hydrolysis UV resistant PUR outer sheath

Nominal overall diameter 10.40mm
Weight: 83 g/m
Specific gravity: 1 +/- 0.04kg/dm3

Pairs suitable for RS 485 and Video

Price: GB£3.49/m x 500mtrs (M.O.Q.)

Manufacturing tolerance +/-10%
Manufacturing lead time: Approximately 4 working weeks from order/Proforma payment
Free UK delivery: 4 working days from end of production
Offer validity at current costs: 30 days

Any questions or feedback about this offer, please do not hesitate to contact me.
I look forward to hearing from you soon.

Many thanks
Kind regards
Andy Timms
Technical Sales
Elmeridge Cables Limited

Bubbles wrote:

kenl wrote:This a quote I got last year.


Hi Ken,

Thank you again for your enquiry, we are pleased to offer as follows:

Cable: 4 x 2 x 24AWG F/UTP CAT6 CW FWNB

Cable 4 x 2 x 24AWG F/UTP CAT6 with cross web, foil screen and stranded conductors
Foamed polyolefine sheath
Hydrolysis UV resistant PUR outer sheath

Nominal overall diameter 10.40mm
Weight: 83 g/m
Specific gravity: 1 +/- 0.04kg/dm3

Pairs suitable for RS 485 and Video

Price: GB£3.49/m x 500mtrs (M.O.Q.)

Manufacturing tolerance +/-10%
Manufacturing lead time: Approximately 4 working weeks from order/Proforma payment
Free UK delivery: 4 working days from end of production
Offer validity at current costs: 30 days

Any questions or feedback about this offer, please do not hesitate to contact me.
I look forward to hearing from you soon.

Many thanks
Kind regards
Andy Timms
Technical Sales
Elmeridge Cables Limited

Did you finally order it?

No it was too much and I am still weighing up the tether I will use. As in fiber optics or copper, my current cat5 is not the best.

Are you running surface power/telemetry or is your sub powered subsea? Are you running straight DC or A/C->D/C converted?

Depending on your power/telemetry requirements, you may not need a commercial tether. If you are just looking for data, are you running straight RS232? Have you considered integrating a modem into the telemetry stream to decrease data loss?

For your power requirements; what kind of voltage are you sending down and what kind of drop are you looking at? Remember, with constant resistance, if you increase voltage, you reduce amperage. Less amperage=smaller conductors=smaller tether requirement.

(Power = IxIxR, and the power lost in the line is then just current and resistance. Reduce either and you reduce the power loss.)

kendelrio wrote:Are you running surface power/telemetry or is your sub powered subsea? Are you running straight DC or A/C->D/C converted?

Depending on your power/telemetry requirements, you may not need a commercial tether. If you are just looking for data, are you running straight RS232? Have you considered integrating a modem into the telemetry stream to decrease data loss?

For your power requirements; what kind of voltage are you sending down and what kind of drop are you looking at? Remember, with constant resistance, if you increase voltage, you reduce amperage. Less amperage=smaller conductors=smaller tether requirement.

(Power = IxIxR, and the power lost in the line is then just current and resistance. Reduce either and you reduce the power loss.)

Ayy suggestions for a cable for full-doublex RS 485 and video transmission and as neutral as possible? Power is onboard.

Bubbles wrote: Ayy suggestions for a cable for full-doublex RS 485 and video transmission and as neutral as possible? Power is onboard.

Not off the top of my head. I've seen some other threads regarding this.

We use multi-mode fibers for our telemetry stream with stepped surface power to 3 phase motors and stepped up/back down A/C for our electrics. (cameras, sonar, depth sensors etc).