Most Common Questions
How Far can I run cable from the antenna to a GPS Source Splitter
Why are splitters Built with 200 Ohm loads on DC Blocked Ports?
How Far can I run cable from the receiving Antenna to a GPS Source Splitter?
What we are concerned with is total signal loss. For high
gain antenna (35dB), most receivers can operate properly with 13dB +/- 2dB
total loss or attenuation from the antenna to the receiver input. For lower
gain antenna (26dB), most receivers function normal with 6dB +/- 2dB total
loss or attenuation from the antenna to the receiver input.
Considerations include the cable loss between the antenna
and the splitter, the splitter loss and the cable loss from the splitter to
the receiving device. Those three things combined cannot exceed the 13dB +/- 2dB
or the 6dB +/- 2dB above.
Remember the passive S12 adds approximately 4dB of loss
and the passive S14 adds approximately 8dB of loss. The only thing left to
do is calculate your cable loss.
Special Note: You can find low loss cable rated at GPS frequencies that are a plenum,
semi-rigid or rigid type. Of course you will pay extra for these types of cables. You can
find the specifications of your cable on the internet. And as always, call or email us and we
will be glad to help you out with any GPS project or installation.
Top
Why are GPS Source Splitters built with 200 OHM loads on DC blocked ports
GPS source splitters can pass DC voltage or block DC voltage on every port. The 200 Ohm loads on DC blocked ports simulate the current draw of an attached antenna. Some GPS receivers will indicate an antenna fault if they do not detect this current draw.
Most GPS receivers supply antenna voltage through the input port. GPS Source splitters pass this DC voltage to the antenna via the Out1 port. Hence, the Out1 ports do not need a 200 Ohm load and the attached receiver will not indicate an antenna fault.
For splitters with the Power Option where antenna voltage is supplied by the splitter, all Out ports are blocked and have a 200 Ohm load. Again, the attached receivers are satisfied with the 200 Ohm load a no antenna fault will be indicated.
Note: Remember, GPS Source products come standard with the customers choice of Plug/Jack (Male/Female) type N, SMA, TNC, or BNC connectors. Mix and match any connector configuration free of charge. We know that eliminating adapters removes excess loss and expense to every GPS distribution set up and configuration.
Top
|
