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-   -   Marine VHF - broadcast FM antenna isolators? (https://www.boatbanter.com/electronics/91159-marine-vhf-broadcast-fm-antenna-isolators.html)

Mika[_2_] February 20th 08 06:42 AM

Marine VHF - broadcast FM antenna isolators?
 

Currently have a car FM with its own antenna just above deck. Wish to
use my mast-mounted marine VHF antenna for receiving broadcast FM as
well. There are many devices available what sort of split the
antenna cable to VHF and FM. Do these in practice provide enough
separation so that I would not "fry" my FM receiver should I transmit
on marine VHF while broadcast FM radio is swhitched on? 25 watts to
receiver could do some damage...

Mika






--

A bad day on the water is better than a great day on land.

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William Andersen February 20th 08 07:31 AM

Marine VHF - broadcast FM antenna isolators?
 
I don't know about a car FM, but I have two Marine VHF-FM radios that use
one antenna.
I have an
a.. SHAKESPEARE ELECTRON
a.. Automatic Two-Way Antenna Selector
a.. Only $84.99 USD
When a radio mic is keyed, the other radio is isolated from the antenna.
Doesn't matter which radio is used, the other is automatically protected.
I've had it for several years and both radios work fine.
When a mic is not keyed, both radios receive. That's convenient for me as I
can scan several channels on one radio and remain on another channel on the
other radio.

" Mika" wrote in message
...

Currently have a car FM with its own antenna just above deck. Wish to
use my mast-mounted marine VHF antenna for receiving broadcast FM as
well. There are many devices available what sort of split the
antenna cable to VHF and FM. Do these in practice provide enough
separation so that I would not "fry" my FM receiver should I transmit
on marine VHF while broadcast FM radio is swhitched on? 25 watts to
receiver could do some damage...

Mika






--

A bad day on the water is better than a great day on land.

Lähetätkö e-mailia? Vaihda osoitteen eka (vai oliko se toka?)
kahdeksikko numeroksi viisi.




Larry February 20th 08 08:14 PM

Marine VHF - broadcast FM antenna isolators?
 
( Mika) wrote in :


Currently have a car FM with its own antenna just above deck. Wish to
use my mast-mounted marine VHF antenna for receiving broadcast FM as
well. There are many devices available what sort of split the
antenna cable to VHF and FM. Do these in practice provide enough
separation so that I would not "fry" my FM receiver should I transmit
on marine VHF while broadcast FM radio is swhitched on? 25 watts to
receiver could do some damage...

Mika







They work but do cause some sensitivity decline in your marine VHF because
of the poor way they are designed, more like a cheap radio than a piece of
RF hardware, which would cost them money to make. They're lossy, both on
incoming and transmitting.

Your VHF antenna is NOT made or tuned for any FM radio band. It's not
going to be a great FM antenna to receive FM stations miles and miles away.
Any consumer FM radio is a terrible piece of equipment, even expensive
ones. They're made to sell, not to perform, and all have poor receivers,
which is why FM broadcasters are running 100,000 watts of power so they can
hear them.

If I were you, I'd leave my VHF piece of safety equipment attached to its
antenna, not make it part of the entertainment system that's not going to
save you from the sinking, if you get my drift.


Larry February 20th 08 08:20 PM

Marine VHF - broadcast FM antenna isolators?
 
"William Andersen" wrote in
:

I don't know about a car FM, but I have two Marine VHF-FM radios that
use one antenna.


An inherently terrible idea for safety at sea.

The weakest, most exposed link in your VHF system has no backup.

So, there you are sinking off Drum Island with ONE dead antenna and two
perfectly good VHF radios unable to call for help from that ship 8 miles
away you can see the top of.

TWO radios should have TWO antenna fed by TWO SEPARATE FEEDLINES and TWO
POWER SOURCES, if possible, and it is. REDUNDANCY is why spacecraft
operate way beyond their expected life.

Please put up even a little Metz Manta 6 on a handrail mount. Do it for
the children, please?


GregS[_3_] February 20th 08 09:05 PM

Marine VHF - broadcast FM antenna isolators?
 
In article , Larry wrote:
"William Andersen" wrote in
:

I don't know about a car FM, but I have two Marine VHF-FM radios that
use one antenna.


An inherently terrible idea for safety at sea.

The weakest, most exposed link in your VHF system has no backup.

So, there you are sinking off Drum Island with ONE dead antenna and two
perfectly good VHF radios unable to call for help from that ship 8 miles
away you can see the top of.

TWO radios should have TWO antenna fed by TWO SEPARATE FEEDLINES and TWO
POWER SOURCES, if possible, and it is. REDUNDANCY is why spacecraft
operate way beyond their expected life.

Please put up even a little Metz Manta 6 on a handrail mount. Do it for
the children, please?


I would agree to have separate FM antenna.
I did share the FM antenna with a CB. That was kinda a mess. The CB
is disconnected now.

greg

Larry February 21st 08 12:30 AM

Marine VHF - broadcast FM antenna isolators?
 
(GregS) wrote in news:fpi4ne$71b$1
@usenet01.srv.cis.pitt.edu:

That was kinda a mess. The CB


The CB was a mess since 1857....(c;)


Mika[_2_] February 21st 08 12:12 PM

Marine VHF - broadcast FM antenna isolators?
 
On Wed, 20 Feb 2008 20:14:51 +0000, Larry wrote:

( Mika) wrote in :


Currently have a car FM with its own antenna just above deck. Wish to
use my mast-mounted marine VHF antenna for receiving broadcast FM as
well. There are many devices available what sort of split the
antenna cable to VHF and FM. Do these in practice provide enough
separation so that I would not "fry" my FM receiver should I transmit
on marine VHF while broadcast FM radio is swhitched on? 25 watts to
receiver could do some damage...

Mika







They work but do cause some sensitivity decline in your marine VHF because
of the poor way they are designed, more like a cheap radio than a piece of
RF hardware, which would cost them money to make. They're lossy, both on
incoming and transmitting.

Your VHF antenna is NOT made or tuned for any FM radio band. It's not
going to be a great FM antenna to receive FM stations miles and miles away.
Any consumer FM radio is a terrible piece of equipment, even expensive
ones. They're made to sell, not to perform, and all have poor receivers,
which is why FM broadcasters are running 100,000 watts of power so they can
hear them.

If I were you, I'd leave my VHF piece of safety equipment attached to its
antenna, not make it part of the entertainment system that's not going to
save you from the sinking, if you get my drift.


You are probably right. Most consumer electronics pieces are not
quality, but overprized junk. Better keep separate antennas. Besides,
have already installed another power bus to feed VHF, nav lights, echo
and log in case main battery fails. Only 6Ah battery standby, but who
need nav lights during summer here in 60 degrees north ;)

Mika



--

A bad day on the water is better than a great day on land.

Lähetätkö e-mailia? Vaihda osoitteen eka (vai oliko se toka?)
kahdeksikko numeroksi viisi.

Larry February 21st 08 03:58 PM

Marine VHF - broadcast FM antenna isolators?
 
( Mika) wrote in :

You are probably right. Most consumer electronics pieces are not
quality, but overprized junk.


Except, curiously, things made in Finland. My Nokia N800 Linux internet
tablet is a fine piece of Finnish equipment, very nicely made. My next
Sellphone will be a Nokia, too, because of it.

Too bad Nokia isn't interested in marine electronics.....



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