SatSig topic:

L-band transmission on optical fibre. Advice please ?

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Oct 27^th, 2016 at 5:18pm

We need to transport L band over fibre ( https://questtel.com/unit/1ch-l-band-over-fiber-transmitter-and-receiver-kit-rg/
) signal. Our distance is ~96 km, but we don't know exactly line attenuation. Can any one recomend right EDFA we found this company's but we never tried there product before
multicom
https://www.multicominc.com/product-category/solutions/video-data-voice/fiber-op...

Is there any preferences in down-converters from C & Ku bands?
Any recommendations?

Oct 27^th, 2016 at 5:18pm

Hello,
Need recommendation for the project, is there any preferences in down-converters from C & Ku bands to LBand

Please advise

Oct 27^th, 2016 at 8:07pm

To down convert from C band or Ku band to L band use a Low Noise Block Downconverter (LNB). If frequency accuracy is important use the Phase Lock Loop (PLL) variety. The most accurate results are obtained with an external 10 MHz reference from indoor reference oscillator based on GPS or Rubidium. The 10 MHz signal is sent up the cable to the LNB, along with DC power.

Regarding the design of RF over optical fibre links this is good reading:
RF-and-Microwave-Fiber-Optic-Design-Guide

Best regards, Eric.

Oct 28^th, 2016 at 1:39am

Could you please recommend down-converter from C & Ku bands to LBand, which brand you would go with ?

Look forward to your reply

Oct 28^th, 2016 at 1:18pm

First, I would consider the least expensive solution and that is to use a conventional LNB directly connected to the antenna feed.

There are considerations of dual polarisation and, in the case of Ku band, upper and lower parts of Ku band. What do you want to receive ?
Some Ku LNBs have multiple outputs. For example low band vertical, low band horizontal, high band vertical and high band horizontal.
Some LNBs have a 'stacking' feature and merge outputs from two different input polarisations. It all depends on what you want to do. If you are sending all signals via fibre then multiplexing the signals will reduce the number of fibres.
Is frequency stability/accuracy important? If so, use PLL type LNBs.

If you intend to use wide band LNAs followed by indoor block down converters then read here:

https://www.vialite.com/resources/guides/what-is-rf-over-fiber-technology/

These units have L band or C or Ku band coaxial cable input, and are not low-noise devices. They are intended to be installed following a wide band LNA and, typically, a splitter.

Try also searching in Google for "RF over fibre".

Best regards, Eric

Oct 28^th, 2016 at 6:37pm

Thank you for your help, we will contact.

Ron