Rb / GPS (opt 132) Frequency Reference General Information

Owned by Kevin Godfrey
Last updated: Sept 18, 2023 by Lee Noble
2 min read

Where can I find specifications?

The brochure is available from the Calnex website.

How do I connect the Rb to a Paragon?

Connection information can be found in the Paragon-X Getting Started Guide. This is available from the Paragon-X application (Help->User Guides->Getting Started Guide) or from your Windows Start menu (Calnex->Documentation->Paragon-X->User Guides->Getting Started Guide).

Is the Rb delivered with an antenna?

Yes, the Rb/GPS Frequency Reference is delivered with the following:

  • Tallysmann TW3442 Rooftop Antenna

  • 3406.19.0003 Huber and Suhner Lightning Arrestor

  • 15m RG-58 coaxial cable

  • 5m RG-58 coaxial cable

Where should I install the antenna?

The antenna must be located where there is direct, constant and line-of-sight view of satellites. Usually the best location is on a roof with no obstructions (such as other buildings or structures) blocking a view of the sky. However, to avoid lightning, the antenna should not be mounted such that it is the highest point in its surrounding area.

What is the maximum length of cable that can be used between the antenna and the Rb / GPS Frequency Reference?

The maximum cable length is determined by the antenna gain, loss in the cable and the minimum required system gain. The following equation is typically used to determine the maximum cable length:

Antenna Gain - Cable Loss >= 15dB

In general, the system should have more than 10dB to 15dB of gain before the receiver input.

If a lightning suppressor is being used then this may also have to be taken into account although they generally have losses less than 1dB (the supplied Huber and Suhner suppressor has a loss of 0.2dB). Connectors may also add some loss (up to 0.5dB per connector) and so these may also need to be taken into account in marginal cases:

Antenna Gain - Cable Loss - Lightning Suppresor Loss - Connector Loss >= 15dB

The Tallysmann (TW3442) antenna supplied with the Rb / GPS Frequency Reference has 40dB gain. When using this antenna (and ignoring the effect of the lightning suppressor and connectors) the maximum cable loss is 25dB.

The maximum cable length is then determined by the loss per metre of cable. This will vary between cable types and manufacturers. Please consult the datasheet for the cable you intend to use.

If a long cable run is required and the requirements above cannot be satisfied, then it is possible to use an in-line amplifier to add additional gain.

Is there an internal battery to maintain frequency in holdover?

No. The Rb / GPS Frequency Reference is intended for lab use and so should be powered-up while in use.