using uhf for am/fm sterio

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dennis23685

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Dec 3, 2007
14
Catalina 250 venice, fl
Hello all,

Was hoping I could get some advise regarding doubling the use of my uhf antenna for am/fm sterio antenna. Can I use a splitter at the mast step and tie into the sterio. Will this work or do I need a separate am/fm antenna.
Thanks for the help.
Dennis
 
Don S/V ILLusion

Don S/V ILLusion

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Sep 25, 2008
7,695
Alden 50 Sarasota, Florida
Any splitter designed for this purpose will work and many are available. The antenna effective length is critical only for the VHF antenna (not uhf) so it will work decently for am/fm receivers.
Keep in mind there is an inherent loss with all splitters. It is not a concern with the am/fm side but could be important in marginal fringe area VHF marine communications, particularly if safety is the purpose of this radio.

Don't be mislead with some of the loss claims when you read their advertizing. You have to add in loss for multiple connectors as well and the total can be significant.

Bottom line - avoid use of splitters if you can.
 
ArtificialReef

ArtificialReef

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Aug 11, 2005
11
Colvin Adryn Mor Newport News, Va
Anytime you have physical splice or connection(like a splitter) you have a 3dB loss in power. That's a reduction of 50%.
 
Don12364

Don12364

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Dec 2, 2003
1,637
Hunter 376 Warsash, England --
Artificial

The 50% loss (3dB) only applies if both signals are in the same frequency band and the splitter has no inbuilt amplifier.
i.e when a splitter is used with AIS there is a loss of range in VHF (reception only if the splitter has a relay for transmit) from a typical 25 miles to 17 miles.
 
Ed Schenck

Ed Schenck

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
I had one but replaced with XM/Sirius. A huge improvement for tunes.
 
Don S/V ILLusion

Don S/V ILLusion

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Sep 25, 2008
7,695
Alden 50 Sarasota, Florida
Donalex said:
The 50% loss (3dB) only applies if both signals are in the same frequency band and the splitter has no inbuilt amplifier.
i.e when a splitter is used with AIS there is a loss of range in VHF (reception only if the splitter has a relay for transmit) from a typical 25 miles to 17 miles.
Click to expand

If you mean to imply there is no loss with a splitter connected to radios of different freq ranges, that is ridiculous. The splitter has no clue to what radio(S) it is connected. Loss is loss and only increases with frequency. and any built-in amplifier in these things is of such a poor design that it increases the noise floor more than a signal.
Do yourselves a favor and avoid them; if you already have one, get rid of it.
 
Don12364

Don12364

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Dec 2, 2003
1,637
Hunter 376 Warsash, England --
Splitters - Don S/V ILLusion

No I did not say that there was no loss caused by a splitter working between two different frequency bands. Such splitters can be, and should be, designed for minimum insertion loss but it so happens that the splitters used for AIS (ch70) and the remainder of the VHF band put 50% of the signal to each receiver with no selective tuning.
I think both you and I are singing from the same hymn sheet when it comes to splitters. My article in the UK's Practical Boat Owner magazine over a year ago condemned them as a possible reduction in range of your reception of the Coastguard's response to your Mayday. This caused several makers/sellers of splitters to respond in their own defence - until I pointed out it actually said 3dB loss in their specs.
Sadly Raymarine are now selling two AIS sets and each includes a splitter with, as I read their spec, "less than 4dB of loss" on the normal VHF channel.
 
A

alexco38

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Sep 25, 2008
1,096
CS 30 Toronto
When you "split" something, it's usually 50-50. Thats 3db or 50% reduction on each side without accounting for the insertion and connector lost. I removed mine.
 
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