Hello,

Expect to purchase an A/B switch box to switch the coax lead from a single
receive-only antenna to one of two scanners.

Got to wonder about using a "Splitter" instead.

What is the typical insertion loss for a Splitter ?
(the Scanner freq's go up close to 1 GHz)

I will always be using, and have On, only one of the receivers at a time.
Thus the other spigot will be always be looking at a receiver that is Off.

Will I still have the insertion loss if only one receiver is on (but the
other receiver that is Off would still be connected to the Splitter) ?

Thanks,
Bob

On Mar 18, 4:32 pm, "Robert11" wrote:
Hello,

Expect to purchase an A/B switch box to switch the coax lead from a single
receive-only antenna to one of two scanners.

Got to wonder about using a "Splitter" instead.

What is the typical insertion loss for a Splitter ?
(the Scanner freq's go up close to 1 GHz)

I will always be using, and have On, only one of the receivers at a time.
Thus the other spigot will be always be looking at a receiver that is Off.

Will I still have the insertion loss if only one receiver is on (but the
other receiver that is Off would still be connected to the Splitter) ?

Thanks,
Bob

A decent splitter, driven by a source whose impedance is the impedance
the splitter is designed for, delivers half the available power to a
matched load on either side, independent of what's hooked to the other
side. A decent splitter should not have more than a dB or so internal
loss. That said, antennas and receiver inputs are seldom very close
to their nominal impedance, so YMMV. In general, though, don't expect
one receiver being on or off to matter significantly to the other
receiver.

Cheers,
Tom
who recently designed, built and installed a 1-to-8 splitter plus
amplifier here at work for a receiver antenna system. The one here
really is good about isolation among the outputs; shorts or opens on
one output affect any of the others by a couple tenths of a dB max.

In message
,
K7ITM writes
On Mar 18, 4:32 pm, "Robert11" wrote:
Hello,

Expect to purchase an A/B switch box to switch the coax lead from a single
receive-only antenna to one of two scanners.

Got to wonder about using a "Splitter" instead.

What is the typical insertion loss for a Splitter ?
(the Scanner freq's go up close to 1 GHz)

I will always be using, and have On, only one of the receivers at a time.
Thus the other spigot will be always be looking at a receiver that is Off.

Will I still have the insertion loss if only one receiver is on (but the
other receiver that is Off would still be connected to the Splitter) ?

Thanks,
Bob

A decent splitter, driven by a source whose impedance is the impedance
the splitter is designed for, delivers half the available power to a
matched load on either side, independent of what's hooked to the other
side. A decent splitter should not have more than a dB or so internal
loss. That said, antennas and receiver inputs are seldom very close
to their nominal impedance, so YMMV. In general, though, don't expect
one receiver being on or off to matter significantly to the other
receiver.

Cheers,
Tom
who recently designed, built and installed a 1-to-8 splitter plus
amplifier here at work for a receiver antenna system. The one here
really is good about isolation among the outputs; shorts or opens on
one output affect any of the others by a couple tenths of a dB max.

Thinking 'cheap', a two-way equal-output cable TV passive
(non-amplified) splitter will have a signal reduction of around 4dB at
each port. This consists of an unavoidable 3dB (because the power is
halved) plus the circuit losses. Typical signal reduction figures are
3.5dB at 5MHz, 4dB at 500MHz and (say) 5dB at 1000MHz. For slightly
better performance at UHF, a satellite splitter might be a little
better, but it may not perform at the lower frequencies.

The maker's spec for the isolation between the output ports will be
about 25dB (theoretically infinite), but only when the source impedance
(ie the antenna feed) is 75 ohms. If you have 50 ohms, it will be lower
(theoretically, it can never better than ~21dB). This is more than
enough.

Because of the unavoidable signal loss, I would hesitate about using an
unamplified splitter. However, if you do use an amplified one, make sure
that it has a good noise figure. Personally, if you don't need the two
receivers to operate at the same time, I'd use a cable TV A/B switch.
--
Ian

Hi Guys,

Thanks for info. and advice.
Appreciate it.

Bob

-----------------------------
"Robert11" wrote in message
. ..
Hello,

Expect to purchase an A/B switch box to switch the coax lead from a single
receive-only antenna to one of two scanners.

Got to wonder about using a "Splitter" instead.

What is the typical insertion loss for a Splitter ?
(the Scanner freq's go up close to 1 GHz)

I will always be using, and have On, only one of the receivers at a time.
Thus the other spigot will be always be looking at a receiver that is Off.

Will I still have the insertion loss if only one receiver is on (but the
other receiver that is Off would still be connected to the Splitter) ?

Thanks,
Bob