Ext spkr for VHF Radio

[Bill Andersen]

I want to use the two stereo speakers of my boats AM/FM/Cassette Player for
my VHF radio. I wired both radios to a Double Pole Double Throw switch. The
AM/FM/Cassette Player works, but the VHF radio volume is so low I can barely
hear it.
The specifications for both radios state 4-8 ohm speakers. The
AM/FM/Cassette Player states 14 watts RMS maximum stereo power, the VHF
radio states 4 watts audio output.
Is there anyway I can use the stereo speakers for both radios? If not, will
the VHF radio have enough power to hear it if I add two of the mini-speakers
designed for it in the rear cockpit area?

 

[Larry]

I want to use the two stereo speakers of my boats AM/FM/Cassette Player for
my VHF radio. I wired both radios to a Double Pole Double Throw switch. The
AM/FM/Cassette Player works, but the VHF radio volume is so low I can barely
hear it.
The specifications for both radios state 4-8 ohm speakers. The
AM/FM/Cassette Player states 14 watts RMS maximum stereo power, the VHF
radio states 4 watts audio output.
Is there anyway I can use the stereo speakers for both radios? If not, will
the VHF radio have enough power to hear it if I add two of the mini-speakers
designed for it in the rear cockpit area?

I'm not sure how you wired it as the VHF radio most likely has a single
speaker output and the stereo has two outputs (right and left) and may
share a common ground. You can use the stereo speakers for both radios,
but you should turn off whichever radio is not connected to the speakers to
avoid blowing out the audio section.

If it were me, I'd add a SINGLE remote speaker to the VHF radio, making
sure it is plugged into a connection designed to power a speaker.

 

[Bill Andersen]

The stereo has a separate output and ground for each speaker.
The VHF has a built-in speaker and a outlet for an external speaker jack.
The DPDT switch has 6 posts, I cut one of the wires from the stereo to each
speaker and ran them to the left and center posts of the switch so, when the
switch is to the left, the stereo is connected to the speakers.
I ran a wire from the external speaker jack of the VHF to the right and
center posts of the switch so, when the switch is to the right, the VHF is
connected to the speakers.

 

[Gary Schafer]

Bill,

It sounds like your wiring is wrong. Without your switch connected,
First check to make sure that the common wire on the stereo is really
at ground on the radio.

Next check to see that one of the wires out of the marine radio is at
ground on the radio.

If both have those leads grounded on each unit then you can do what
you want with the double pole double throw switch.

Leave the common speaker leads grounded to the common lead on the
stereo. Place each of the other speaker leads on the CENTER poles of
the switch. (one on each pole) On one end of the switch place each of
the leads from the stereo. Now when the switch is in one position the
speakers will be hooked as they normally were to the stereo. In the
other position of the switch one lead of each speaker will be
disconnected from the stereo. In that position of the switch the
speakers will now be hooked to the opposite end of the switch.

You can hook the ungrounded lead of the marine radio to one of the
poles on the opposite end of the switch from where the stereo radio is
hooked.
The grounded speaker lead from the marine radio would get connected to
the grounded connection of the stereo and speaker ground junction.

Now with the switch in the marine radio position the stereo is
disconnected on both channels and the marine radio is connected to ONE
of the speakers. If you want both of the speakers to be connected to
the marine radio place a jumper wire between the two terminals on the
end of the switch that the marine radio is connected to. (one of those
would have been the only unused pole on the switch)

Regards
Gary

The stereo has a separate output and ground for each speaker.
The VHF has a built-in speaker and a outlet for an external speaker jack.
The DPDT switch has 6 posts, I cut one of the wires from the stereo to each
speaker and ran them to the left and center posts of the switch so, when the
switch is to the left, the stereo is connected to the speakers.
I ran a wire from the external speaker jack of the VHF to the right and
center posts of the switch so, when the switch is to the right, the VHF is
connected to the speakers.

 

[Bill Andersen]

Thanks, Gary. I thought that was how I wired it. I'll print your post and
take it with me the next time I have a chance to tinker with the speakers.

Bill

Bill,

It sounds like your wiring is wrong. Without your switch connected,
First check to make sure that the common wire on the stereo is really
at ground on the radio.

Next check to see that one of the wires out of the marine radio is at
ground on the radio.

If both have those leads grounded on each unit then you can do what
you want with the double pole double throw switch.

Leave the common speaker leads grounded to the common lead on the
stereo. Place each of the other speaker leads on the CENTER poles of
the switch. (one on each pole) On one end of the switch place each of
the leads from the stereo. Now when the switch is in one position the
speakers will be hooked as they normally were to the stereo. In the
other position of the switch one lead of each speaker will be
disconnected from the stereo. In that position of the switch the
speakers will now be hooked to the opposite end of the switch.

You can hook the ungrounded lead of the marine radio to one of the
poles on the opposite end of the switch from where the stereo radio is
hooked.
The grounded speaker lead from the marine radio would get connected to
the grounded connection of the stereo and speaker ground junction.

Now with the switch in the marine radio position the stereo is
disconnected on both channels and the marine radio is connected to ONE
of the speakers. If you want both of the speakers to be connected to
the marine radio place a jumper wire between the two terminals on the
end of the switch that the marine radio is connected to. (one of those
would have been the only unused pole on the switch)

Regards
Gary

 

[Bill Andersen]

....in parallel.. I'm trying to remember what that is.
But, only one radio powers the speakers at a time, that's why I used a DPDT
switch.
Bill

 

[Rheilly Phoull]

You need a 4-pole switch to be safe. Switch BOTH wires on BOTH
speakers, not just the hot lead. Not all amps use ground (negative
battery) for their return wires.





Larry W4CSC

NNNN

I dunno but taking the "Kiss" theory, it might be best to just have another
extention speaker for the radio ??
Not like it will break the bank and you dont have to remember to throw the
switch.
A small 'coms" type speaker would do it and you would not be compromising
either system.

 

[Larry]

I dunno but taking the "Kiss" theory, it might be best to just have another
extention speaker for the radio ??
Not like it will break the bank and you dont have to remember to throw the
switch.
A small 'coms" type speaker would do it and you would not be compromising
either system.

Absolutely! It's really the best way to do it and not at all expensive.

 

[Bruce in Alaska]

I dunno but taking the "Kiss" theory, it might be best to just have another
extention speaker for the radio ??
Not like it will break the bank and you dont have to remember to throw the
switch.
A small 'coms" type speaker would do it and you would not be compromising
either system.

Another solution to this problem is to use a Dual Voicecoil Speaker.
Motorola built a very nice Marine VHF Radio years ago called a MODAR
Triton that used one of these in the Bridge to Bridge version. This
radio has two receivers and both drive a single speaker with two
individual voicecoils. Worked very slick. I have a number of the
speakers that I salvaged from these as the radio's died, and use them
just for this purpose. I have seen a few speakers with similar setups
in Jameco on occasion.

Bruce in alaska

 

[Harry Krause]

When my SECOND unprotected cheap Sea Ray AM/FM/cassette player croaked
from the salt spray on it, it tore it all out and mounted my Icom M59
in its hole. The Icom now powers BOTH "marine speakers" hooked simply
in parallel in the cockpit. Works great, plenty of volume.....

But how does it handle those cassettes???

 

[Bill Andersen]

The switch I bought is called DPDT. It has six posts: 2 left, 2 center, 2
right.
I intended to use the two on the left side for the left and right stereo
channels and the two on the right side for the VHF (jumpered to both posts).
The center posts are for the grounds of both speakers.
I know I can add a separate speaker for the VHF radio. My idea was to use
the existing stereo speakers for the VHF radio with the option of switching
them back to the stereo.
I sometimes place my hand held radio in a holder mounted on the engine
compartment. That's OK, but uses up the batteries.

 

[Peter Bennett]

The switch I bought is called DPDT. It has six posts: 2 left, 2 center, 2
right.
I intended to use the two on the left side for the left and right stereo
channels and the two on the right side for the VHF (jumpered to both posts).
The center posts are for the grounds of both speakers.

Not quite right...

Connect the "hot" wires from the stereo to the two left terminal, the
"hot" wires to the two speakers to the center terminals, and the "hot"
wire from the VHF to the two right terminals. The ground wires from
speakers, stereo, and VHF should all be connected together, and
connected to the switch.

This assumes that one side of each stereo speaker is really grounded -
if this is no so, you need a four pole switch, and will need to switch
both sides of both speakers.

 

[Larry]

The switch I bought is called DPDT. It has six posts: 2 left, 2 center, 2
right.
I intended to use the two on the left side for the left and right stereo
channels and the two on the right side for the VHF (jumpered to both posts).
The center posts are for the grounds of both speakers.
I know I can add a separate speaker for the VHF radio. My idea was to use
the existing stereo speakers for the VHF radio with the option of switching
them back to the stereo.
I sometimes place my hand held radio in a holder mounted on the engine
compartment. That's OK, but uses up the batteries.

That assumes that both devices use ground as the other conductor. If your
stereo does not use ground as the second speaker terminal, you will have
problems. Really, this is not a good idea, as someone might turn on the
stereo, not hear anything and turn it up which can damage the outputs.
Same thing can happen to the VHF.

A second speaker is cheap and safer!

As for mounting a handheld on the console, why not just get a 12 volt
adapter for it?

 

[Marcus AAkesson]

The switch I bought is called DPDT. It has six posts: 2 left, 2 center, 2
right.
I intended to use the two on the left side for the left and right stereo
channels and the two on the right side for the VHF (jumpered to both posts).
The center posts are for the grounds of both speakers.
I know I can add a separate speaker for the VHF radio. My idea was to use
the existing stereo speakers for the VHF radio with the option of switching
them back to the stereo.
I sometimes place my hand held radio in a holder mounted on the engine
compartment. That's OK, but uses up the batteries.

That connection could destroy Your amplifiers..

To be on the safe side You need a 4-pole 2-position switch (4+4+4=12
terminals).


/Marcus
[/QUOTE]

 

[Peter Bennett]

Not quite right...

Connect the "hot" wires from the stereo to the two left terminal, the
"hot" wires to the two speakers to the center terminals, and the "hot"
wire from the VHF to the two right terminals. The ground wires from
speakers, stereo, and VHF should all be connected together, and
connected to the switch.

Oops - the ground wires should NOT be connected to the switch!