Radios and external speakers
Submitted: Tuesday, Feb 08, 2005 at 23:51
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20263
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Member - Melissa
Well now that we have the
HF radio sitting at
home on the
kitchen bench, thoughts have turned to the installation process. The remote head unit will go into the roof console which already houses a UHF and 27 meg radio and an external speaker to which both radios are connected. The HF came with a GME external speaker the same as our existing one. What I'm now wondering is this...is there any reason we couldn't also connect the HF to the existing speaker or should we install a separate speaker. Obviously we would have the other radio's off when transmitting and receiving...
:o) Melissa
Reply By: Mike Harding - Wednesday, Feb 09, 2005 at 07:31
Wednesday, Feb 09, 2005 at 07:31
DO NOT directly connect more than one radio to one speaker - even if one of the radios is turned off.
It _may_ work with a particular radio(s) but even when one of the radios is off it's audio output stages are still "seeing" the voltage/current from the radio which is turned on and they may place an electrical load across the working radio in such a way that one or both of the radios will suffer damage.
If you want do this do it via a 2 pole 3 way switch (Dick Smith / Jaycar should sell them) and use that to switch each radio independently to a single speaker. If you don't understand; ask and I'll do a diagram.
Have fun with your new set :)
Mike Harding
mike_harding@fastmail.fm
AnswerID:
97384
Follow Up By: Member - Melissa - Wednesday, Feb 09, 2005 at 10:55
Wednesday, Feb 09, 2005 at 10:55
Thanks for the advice Mike. I guess we'll install the extra speaker. Having to manually switch between the radios would kinda defeat the purposes of scanning or we run the risk of missing a direct transmission or sellcall. Damn, we were hoping to take the easy way out ;-)
:o) Melissa
FollowupID:
356028
Reply By: Member - Banjo (SA) - Wednesday, Feb 09, 2005 at 08:14
Wednesday, Feb 09, 2005 at 08:14
Melissa - welcome to the world of HF ! Re the speakers..... I'm no techo (Mike must be) but I've never connected a speaker to multiple devices. Also, you will have occasion with incoming traffic where you just might have more than one unit on at a time. My GME UHF has inbuilt of course, the 27 Meg HF speaker (Uniden PC122XL) is under the dash (works very
well) and the Barrett 950 is in a foam box on the end of the lead, that is placed here and there according to need. This Barrett speaker is usually on the dash in the corner while mobile, but can be put out on the roof or bonnett when cooking dinner by the campfire etc - that way we can monitor sked traffic. BTW... re the 27 meg speaker ... its under the drivers side dash pointing at the floor - while mobile, you would swear that the sound is coming straight at you from the windscreen - odd, but great ! Pics at homepages.picknowl.com.au/darian
AnswerID:
97391
Reply By: joc45 - Wednesday, Feb 09, 2005 at 12:30
Wednesday, Feb 09, 2005 at 12:30
To be safe, use separate speakers.
IF the 2-ways each use an earth for one speaker lead, then the speakers can be shared, but then only with a resistor in each active lead from the radio (about 3-5 ohms). If the 2-way uses an audio amplifier with a bridged output, where both legs of the output are above earth, then you could do damage by sharing the speaker.
Small 2-way speakers are cheap, and can be hidden under the dash. The tinnier the speaker, the clearer it sounds on a 2-way; you don't want a speaker with any bass.
Gerry
AnswerID:
97428