PTP 670 Connectorized ODU to external antenna installation

Products PTP
1

Hi,

Currently my design between offshore platform to onshore telecom tower using PTP 670 Connectorized ODU (distance > 27m).
Antenna height at telecom tower is 51m from ground. We plan to install the ODU inside existing room near the telecom tower. However, from the LinkPlanner the LMR400 RF cable could not be set to more than 3.4m or the % reliability will not be able to achieved. Can we use different cable instead? Or for this setup, the ODU is required to be mount near the external antenna (at 51m)?

Thank you

2

For maximum gain, it would be best for you to use as short RF jumper from the radio to the antenna as possible. The PTP670 (and most of Cambium’s radios) are designed to use PoE and ethernet to the radio, so the radio can be mounted as close to or directly to the antenna. By doing it this way, you can most likely use a smaller sized/lower gain dish for your application as well.

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3

Does this means that I can’t install the ODU inside a cabinet below the tower?

4

You can, but then, as you’ve indicated, you’d have a long run of LMR from the ODU to the antenna. The longer the LMR cable the greater the TX loss, and the larger the antenna you must use to compensate.

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5

Can I use waveguide instead of coaxial cable?

6

I’ve never heard of anyone using a waveguide between the PTP670 and the antenna. I’m not sure what the reduction in attenuation would be using a waveguide VS. a high end LMR cable.

The PTP670 is hardened and designed to be used in a harsh environment, and is ideally placed near the antenna. It’s going to be far cheaper and easier to install shielded, outdoor, UV stabilized CAT6 cable up the tower then it’s going to be to install a waveguide, or even LMR cable.

I feel like @Douglas_Generous might have some comments on this subject.

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7

A short run of LMR is better than a long wave guide at the power levels we are talking about in this application.

If this was a close coupled radio to antenna like the ptp8xx radios then that is a different story, but the wave guide is literally less than 12" long from feed assembly to matching orface and secondary reflector.

LMR400 would be fine for most cable runs up to 10m, but then 3/4" Heliax should be used to compensate for the capacitive losses of the cable.

Considering the application and the radio, mount a conduit to the radio (liqui-tight threads right in) and have the cat5 (or cat6) cable inside the conduit and mount the radio beside the antenna. Use self vulcanizing rubber tape to seal all connections.

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8

Noted.
How do I install the ODU with LPU on the tower? Behind or near the antenna? We are using RDH4510C at the tower (1 Main and 1 Secondary). So two ODUs will be at the tower as well. Bottom LPU shall be inside a building? Is the PSU the AC injector unit?

Bottom LPU to PSU

9

Use these for your ethernet cables:

They do not have to be from this company or these exact models, just a gigabit compatible version for any of the ptp radios (warning ptp250/300 are not gigabit ethernet radios)

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10

The optical fiber cable shown in this drawing is the one that carries the remote transmission data (video, voice, PCS, etc)?

How about the Network termination equipment? What is its purpose? Can this equipment be excluded from our design?

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Thank You

11

You don’t actually need the optical cable for data. You can supply both power and data to the ODU via the Power over Ethernet interface.

The network terminating equipment is your equipment… e.g. a switch or router or server.

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12

if you buy Cambium LPU, you will get 2 pcs LPU in a Box, place 1 LPU Near your PTP670 ( i usually put it under the ODU) on The tower, then place the others LPU near the ground. dont forget to grounding all the LPU.

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13

I would just mount it outdoors, so I wouldn’t recommend using a long Coax run.

But if you have to, look at LDF4-50A, Heliax cable or btter

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