A resistive splitter has essentially no useful port-to-port isolation, in
addition to the
excess splitting loss problem. For this reason, resistive splitters are
usually used
only when very broad frequency ("DC to daylight") coverage is needed.
Many RF splitters are of the Wilkinson variety, or some variant thereof.
In principal
these have good isolation between the output ports over some useful
frequency
range, *but if and only if the source impedance well matched to Zo*. This
last point
is often overlooked, which is unfortunate because many sources are in fact
rather
poorly matched.
So if the system need includes good isolation between output ports of a
splitter, it
is best to sprinkle the system with amplifiers and attenuators, which if
properly
chosen and configured will provide excellent isolation between output ports
regardless.
Dana
On Tue, Jun 29, 2021 at 7:45 AM Bob kb8tq <kb...@n1k.org> wrote:
> Hi
>
> Pretty much *any* splitter will have issues with outputs being
> un-terminated.
> Resistive splitters are really no worse that others. The problem that they
> have
> is 6db of loss per split rather than 3db.
>
> The Symmetricom units are not immune to this. They have a single amplifier
> that
> drives a splitter.
>
> A “DC output” module or receiver normally will be quite happy running into
> a
> blocking capacitor. The dirt cheap ebay parts seem to do fine. It is rare
> to find
> a device that refuses to work this way. The “why” is that basement crazies
> aren’t
> the only ones to run splitters …..
>
> Bob
>
> > On Jun 29, 2021, at 2:16 AM, Julien Goodwin <time-n...@studio442.com.au>
> wrote:
> >
> > I keep forgetting to do a thread about this.
> >
> > I recently (er, perhaps a year ago) picked up a Microlab unit, and was
> > very disappointed, notably the output simply isn't built to handle being
> > plugged into units that provide antenna power, with each port ending up
> > having a DC path to ground (at 200 ohm, so not too terrible, but it's
> > still not great). Plus being a simple resistive splitter it's not ideal
> > if all outputs aren't terminated.
> >
> > Luckily the Sysmocom unit mentioned elsewhere is fine with this (up to
> > 12v because I specifically talked to them about this exact issue when
> > they were working on it).
> >
> > On 27/6/21 1:49 pm, lstosk...@cox.net wrote:
> >> I seem to have an gathering of GPS antenna on my window ledge. I seem
> to have missed info on building a splitter/amp to take one signal and
> distribute it. Quick reference? N0UU
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