[time-nuts] GPS antenna splitters
Brian Kirby
kilodelta4foxmike at gmail.com
Fri Mar 26 21:54:13 UTC 2010
When I first got started using GPS timing receivers, I used direct
broadcasting satellite cable splitters. They are designed to pass DC,
and usually good to 1.5 to 2 Ghz.
If you need amplification you can also use DBS inline amplifiers - but
they need 12-18 volts to power them - so you would have to use a couple
of bias tee's, one for amplifier power and another in front of the
amplifier to provide antenna power (a lot are 5 volts - you need to
check this).
Symmetricom made splitters that also amplified the signal, and use the
voltage from the GPS receiver to power it. You can usually see a 2 port
version of this for under $50 on flea-bay. There are also 4 port
versions. These are called active GPS splitters. The amplification is
enough to get over the splitter loss and usually no more - so you have
to have a good signal to them.
Arthur Dent wrote:
> Dan Rae-"When I only had two gps units in the dim and distant past, I
> used a passive splitter made from a Minicircuits (MCL) ZAPD-2 unit bought
> at the swap meet for $1, with a 100 pF series blocking cap in one of the
> output ports. If the receiver connected to the other port complains,
> you can add some resistance to ground to fool it."
>
>
> While a resistive splitter with one capacitively coupled output will
> work fine, You can insert a simple "T" in series with the GPS that
> will supply the power and the antenna. Then feed the other leg of the
> "T" through a capacitor (with a 220-330 ohm resistor to ground) to the
> second receiver-amounts to about the same thing as the splitter. Almost
> any value capacitor around 47-100pf should work. This will at least
> let you run both GPSDOs until you can find a better splitter/amp at a
> reasonable price.
>
>
>
>
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