I want to put 2 scanners on a diamond d discone antenna. is this possible
without to much loss?
thanks

It is possible.

There will be some loss.

Adding a preamp before a splitter tends to overload the front ends of my
scanners with paging services.


"TongSlinger" wrote in message
...
I want to put 2 scanners on a diamond d discone antenna. is this possible
without to much loss?
thanks

"TongSlinger" wrote in message
...
I want to put 2 scanners on a diamond d discone antenna. is this possible
without to much loss?
thanks
----------------------------------------------------------------------------------------

If you buy the 5-10$ variety from Rat Shack you first are going have
to convert from F type to BNC connector, because they are a made for
tv device. You will get a small loss from the 2 added adapters, and the
splitter will be around -3.5db loss. From input to splitter to the scanners
input it will be close to a -4db loss. Then there is Stridesberg, who does
sell splitters (passive and active) that have BNC connectors. The active
ones will show no loss and the passive will be -3.5db loss again. If
you go with Stridesberg be prepared to write a healthy sized check,
but they are close to mil-spec as you can get and is very good stuff.
Dont let the -3.5db loss scare you,, most times you wont know the
difference, unless you are in a very weak signal area.



J

"TongSlinger" wrote in message
...
I want to put 2 scanners on a diamond d discone antenna. is this possible
without to much loss?
thanks
-----------------------------------------------------------------------------------------

Forgot to add an important point. If you have a coax run of more than
10-20 feet please dont use RG 58. You will get more loss from it than
the splitter especially at the higher freqs. If you dont want to/cant run
the bigger heavier coax i.e. RG 213 go with RG 6. Its a 75 ohm cable
instead of 50 but has very good loss rates and the difference in impedance's
will be negligible and its the same basic diameter of RG 58.


J

thanks guys for the info.

I have another question if I put the antenna half way up the tower will I
have decreased signal coming into the antenna through the triangular tower.
would this not let the antenna be truly Omni? my tower is about 75 feet tall
and I do not have access to the top of the tower?


"Jeff" wrote in message
news:AKQZg.245250$1i1.51592@attbi_s72...

"TongSlinger" wrote in message
...
I want to put 2 scanners on a diamond d discone antenna. is this possible
without to much loss?
thanks
-----------------------------------------------------------------------------------------

Forgot to add an important point. If you have a coax run of more
than
10-20 feet please dont use RG 58. You will get more loss from it than
the splitter especially at the higher freqs. If you dont want to/cant run
the bigger heavier coax i.e. RG 213 go with RG 6. Its a 75 ohm cable
instead of 50 but has very good loss rates and the difference in
impedance's
will be negligible and its the same basic diameter of RG 58.


J

On Mon, 23 Oct 2006 01:20:04 -0500, "TongSlinger"
wrote:

I have another question if I put the antenna half way up the tower will I
have decreased signal coming into the antenna through the triangular tower.
would this not let the antenna be truly Omni? my tower is about 75 feet tall
and I do not have access to the top of the tower?

Depending on the distance between the tower and the antenna, and the
frequency, you'll have a directional antenna pointing somewhere -
either away from the tower, side-to-side relative to a line between
the antenna and tower or somewhere between the two. You'd have to
mount the antenna at least 3 or 4 wavelengths at the lowest frequency
you're interested in (which would be around 25 feet at 150 MHZ,
further for aircraft or VHF-lo) - 6 to 10 wavelengths is better - to
get back a somewhat circular pattern.

Since you'll be using the antenna at widely different frequencies
there's no one solution unless the transmitters you want to monitor
just happen to all be exactly where the antenna pattern points for
that frequency. If you're that lucky, buy all the lottery tickets you
can find - they'll all be winners.

thanks for all the good info on a subject I'm just starting to learn


"Al Klein" wrote in message
...
On Mon, 23 Oct 2006 01:20:04 -0500, "TongSlinger"
wrote:

I have another question if I put the antenna half way up the tower will I
have decreased signal coming into the antenna through the triangular
tower.
would this not let the antenna be truly Omni? my tower is about 75 feet
tall
and I do not have access to the top of the tower?

Depending on the distance between the tower and the antenna, and the
frequency, you'll have a directional antenna pointing somewhere -
either away from the tower, side-to-side relative to a line between
the antenna and tower or somewhere between the two. You'd have to
mount the antenna at least 3 or 4 wavelengths at the lowest frequency
you're interested in (which would be around 25 feet at 150 MHZ,
further for aircraft or VHF-lo) - 6 to 10 wavelengths is better - to
get back a somewhat circular pattern.

Since you'll be using the antenna at widely different frequencies
there's no one solution unless the transmitters you want to monitor
just happen to all be exactly where the antenna pattern points for
that frequency. If you're that lucky, buy all the lottery tickets you
can find - they'll all be winners.

This is an easy one. Figure 3.0 db loss, using a standard CATV splitter.
Is "to much loss" the same as "too much loss?"

Respectfully,

Hunchy




"TongSlinger" wrote in message
...
I want to put 2 scanners on a diamond d discone antenna. is this possible
without to much loss?
thanks

On Mon, 06 Nov 2006 00:16:47 GMT, "Hunchy" wrote:

This is an easy one. Figure 3.0 db loss, using a standard CATV splitter.

That's 3db inherent loss due to splitting. (Each signal is half the
original signal, or -3db.) With most TV splitters, add anywhere from
6db to 20db additional loss in the components in the splitter.

And ALL output ports must be terminated. If you move the scanner from
one cable to the other you'll get additional loss due to the
unterminated cable. (If there are more ports than scanners, you have
to connect a terminating resistor to each unused port.)