I have a pair of speakers in the cockpit coaming for the AM/FM radio..

I would like to figure out a way to connect the VHF external speaker to one
of these, so I can hear any calls on it in scan or monitoring of ch16.

Both radios are below deck so I can only hear them in the cockpit on a
remote speaker..

I know I could just use a toggle switch, but would prefer to find a way to
combine both outputs so the VHF would be heard over the AM/FM output.

Is there a simple way to do this and prevent one unit from harming the
other??

Steve
s/v Good Intentions

On Wed, 4 Feb 2004 08:45:08 -0800, "Steve" wrote:

I have a pair of speakers in the cockpit coaming for the AM/FM radio..

I would like to figure out a way to connect the VHF external speaker to one
of these, so I can hear any calls on it in scan or monitoring of ch16.

Both radios are below deck so I can only hear them in the cockpit on a
remote speaker..

I know I could just use a toggle switch, but would prefer to find a way to
combine both outputs so the VHF would be heard over the AM/FM output.

Is there a simple way to do this and prevent one unit from harming the
other??

Steve
s/v Good Intentions


Two methods come to mind:
The first is the "simple" way...use an andio transformer for each channel.
The transformer would have two primary windings, and one secondary, which
would drive the speakers. One primay is connected to the sound system, the
other to the VHF radio.

A little more complicated way would be to use a VOX (voice operated relay)
connected to the VHF, which would disconnect the stereo, and cut thru the VHF.
This has the advantage of cutting out the stereo when the VHF is active.

I lied..there are three methods....the third is a combination of the first two., except
now the stereo is reduced by a certain amount when the VHF is active.

HTH
Norm

On Wed, 04 Feb 2004 17:52:39 -0800, engsol
wrote:

On Wed, 4 Feb 2004 08:45:08 -0800, "Steve" wrote:

I have a pair of speakers in the cockpit coaming for the AM/FM radio..

I would like to figure out a way to connect the VHF external speaker to one
of these, so I can hear any calls on it in scan or monitoring of ch16.

Both radios are below deck so I can only hear them in the cockpit on a
remote speaker..

I know I could just use a toggle switch, but would prefer to find a way to
combine both outputs so the VHF would be heard over the AM/FM output.

Is there a simple way to do this and prevent one unit from harming the
other??

Steve
s/v Good Intentions


Two methods come to mind:
The first is the "simple" way...use an andio transformer for each channel.
The transformer would have two primary windings, and one secondary, which
would drive the speakers. One primay is connected to the sound system, the
other to the VHF radio.

A little more complicated way would be to use a VOX (voice operated relay)
connected to the VHF, which would disconnect the stereo, and cut thru the VHF.
This has the advantage of cutting out the stereo when the VHF is active.

I lied..there are three methods....the third is a combination of the first two., except
now the stereo is reduced by a certain amount when the VHF is active.

HTH
Norm


No you can't do that with a transformer! The transformer is not going
to isolate one radio from the other. Just because it has two primary
windings will not keep one radio from feeding into the other. A
transformer does not know primary from secondary.

The vox idea would work though.

But it is so much simpler to use 2 speakers.

Regards
Gary

Steve wrote:
I have a pair of speakers in the cockpit coaming for the AM/FM radio..

I would like to figure out a way to connect the VHF external speaker
to one of these, so I can hear any calls on it in scan or monitoring
of ch16.

Both radios are below deck so I can only hear them in the cockpit on a
remote speaker..

I know I could just use a toggle switch, but would prefer to find a
way to combine both outputs so the VHF would be heard over the AM/FM
output.

Is there a simple way to do this and prevent one unit from harming the
other??

Steve
s/v Good Intentions

Why don't you simply connect on of these speakers to the VHF and leave the
other connected to the AM/FM radio? Please don't tell me that this would
destroy the stereo effect, there probabl;y isn't any stereo effect where
they are, in the cockpit combing


Remove "nospam" from return address.

Steve wrote:

Is there a simple way to do this and prevent one unit from harming the
other??

Look at general aviation intercoms of the portable variety.
They are designed to mute the entertainment audio when a
communications radio becomes active. The price may be a bit
high but you may find a used one on Ebay and there are kit
options available from places like RST in Grass Valley CA.

Rick

There are several ways to do it but I would not recommend it. A decent
audio speaker has to much range for a VHF audio output. The wide
response range will make the sound muddy and harder to understand. VHF
speakers have very narrow response range on purpose. It makes the sound
crisper.

Steve wrote:
I have a pair of speakers in the cockpit coaming for the AM/FM radio..

I would like to figure out a way to connect the VHF external speaker to one
of these, so I can hear any calls on it in scan or monitoring of ch16.

Both radios are below deck so I can only hear them in the cockpit on a
remote speaker..

I know I could just use a toggle switch, but would prefer to find a way to
combine both outputs so the VHF would be heard over the AM/FM output.

Is there a simple way to do this and prevent one unit from harming the
other??

Steve
s/v Good Intentions



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Please post a followup if you find out how to do this.
I was unsucesful in doing this in my boat, a 19' runabout.
I tried using a double pole double throw switch so that I could hear either
the VHF radio or the AM/FM/Casette Player from the stereo speakers in the
rear of the boat. My intent was to be able to select which radio was heard
over the stereo speakers.
I settled for a headphone and separate mini speaker for the VHF radio.

"Steve" wrote in message
...
I have a pair of speakers in the cockpit coaming for the AM/FM radio..

I would like to figure out a way to connect the VHF external speaker to
one
of these, so I can hear any calls on it in scan or monitoring of ch16.

Both radios are below deck so I can only hear them in the cockpit on a
remote speaker..

I know I could just use a toggle switch, but would prefer to find a way to
combine both outputs so the VHF would be heard over the AM/FM output.

Is there a simple way to do this and prevent one unit from harming the
other??

Steve
s/v Good Intentions

wrote in message
...
On Fri, 6 Feb 2004 07:56:10 -0800, "William G. Andersen"

Using a toggle switch to suddenly remove the load from the output of
the Stereo probably isn't such a great idea.

Oh boy. There this myth again. This is no problem at all.

Meanwhile the one really useful comment I saw was that stereo speakers
really aren't ideal for VHF anyway.

Indeed famous for VHF or any radio use are speakers from Peiker. They act
like a voice band filter, giving you superb voice quality.

Meindert

wrote in message
...
On Fri, 6 Feb 2004 17:21:14 +0100, "Meindert Sprang"
wrote:
Based on what? Running a high powered amp without a proper load on it
can cause rapid failure.

Give me one reason why.... (audio amp, that is. HF/VHF is a different story)

Meindert

I agree, get an aviation interface that has an entertainment channel. The
more expensive panel mount audio panels may not have the frequency response
for stereo though. Most aviation panels are designed to pass the standard
communications 300-3300 Hz frequencies, and not hi-fi entertainment. Ask
before you buy though, as the entertainment channel may only be monaural,
not stereo as the entrainment source on a small plane is frequently the ADF
switched to the Am broadcast band.
Thanks Rick for mentioning RST...I just checked their website. I thought
they went out of business years ago due to a divorce or something. Nice to
see Jim is back in business again. He used to make aviation test equipment
and even a transceiver kit, that you sent back end after assembly for final
alignment and FCC/FAA sticker.
Doug K7ABX, formerly owned by Beech Musketeer N2392L
"Rick" wrote in message
link.net...
Steve wrote:

Is there a simple way to do this and prevent one unit from harming the
other??

Look at general aviation intercoms of the portable variety.
They are designed to mute the entertainment audio when a
communications radio becomes active. The price may be a bit
high but you may find a used one on Ebay and there are kit
options available from places like RST in Grass Valley CA.

Rick