Thor Broadcast F-RFoF-TX/RX Bi-Directional CATV RF over Fiber Kit | 45-1000 MHz Forward | 5-42 MHz Return Path

Two-Way Cable Service over Fiber

Cable television is not a one-way service: channels travel downstream from the headend while modem traffic returns on lower frequencies. Replacing a long coaxial run therefore means carrying both directions. The Thor F-RFoF-TX/RX does exactly that over fiber, extending reach without the power loss that copper suffers, so a distant building keeps full television and internet service from the same headend.

Forward Path and Return Path

The forward path carries CATV channels in the 54 to 1000 MHz range from the headend using a 1550 nm DFB laser, at an input level of 80 dBuV plus or minus 5, equivalent to +15 to +25 dBmV, with flatness within 0.5 dB. The return path carries 5 to 42 MHz data from the endpoints back toward the headend at an output level of 90 dBuV or more, also within 0.5 dB flatness.

Optical Interfaces and Link Figures

Input optical power is -12 to +3 dBm with adjustable optical AGC from +2 to -7 dBm, across input wavelengths from 1260 to 1600 nm, with optical return loss above 45 dB on single-mode fiber and SC/APC connectors. Forward output optical power is 1 mW, which is 0 dBm, at 1550 nm plus or minus 10 nm. Link figures are C/N of 51 dB or better with C/CTB and C/CSO of 60 dB or better.

RF Impedance, Matching and Headroom

Both directions use 75 ohm impedance, with output return loss of 14 dB or better on the return path and input return loss of 14 dB or better on the forward path, so standard cable plant components match without padding. NPR dynamic range is 30 dB or better on the return path, which gives room for several modems to share the upstream without the noise floor rising into the service.

Headend and Field Units

F-RFoF-TX is the headend-side unit, combining the 1550 nm forward transmitter with a return path receiver, while F-RFoF-RX is the field-side unit, combining a forward receiver with a return path transmitter. Ordered together as F-RFoF-TX/RX they form one complete link. Cable operators, hotels, campuses and MDUs extending television and cable modem service to distant buildings are the usual customers for this pairing.