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#1
posted to rec.boats.building
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speakers
Sorry, I lost the thread to a "view," but Radio Shack on-line has a $20
extension speaker http://www.radioshack.com/product/in...entPage=search For "waterproof," stick it in a big baggie. Roger http://home.insightbb.com/~derbyrm |
#2
posted to rec.boats.building
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speakers
I'm very uneasy about speakers whose position or orientation is not fixed.
They can seriously derange a magnetic compass. I'd much prefer that speakers be in a fixed location and orientation. None within several feet of the compass. "derbyrm" wrote in message news:F6lSf.31888$oL.11786@attbi_s71... Sorry, I lost the thread to a "view," but Radio Shack on-line has a $20 extension speaker http://www.radioshack.com/product/in...entPage=search For "waterproof," stick it in a big baggie. Roger http://home.insightbb.com/~derbyrm |
#3
posted to rec.boats.building
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speakers
Marine-type speakers are generally shielded (as are speakers intended
for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Jim Conlin wrote: I'm very uneasy about speakers whose position or orientation is not fixed. They can seriously derange a magnetic compass. I'd much prefer that speakers be in a fixed location and orientation. None within several feet of the compass. "derbyrm" wrote in message news:F6lSf.31888$oL.11786@attbi_s71... Sorry, I lost the thread to a "view," but Radio Shack on-line has a $20 extension speaker http://www.radioshack.com/product/in...entPage=search For "waterproof," stick it in a big baggie. Roger http://home.insightbb.com/~derbyrm |
#4
posted to rec.boats.building
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speakers
Is the function of the shielding to keep the speaker from picking up the RF
noise from nearby electrical equipment or to contain the influence of the speaker's permanent magnet? Bring a hand compass to the store to test this. "chuck" wrote in message link.net... Marine-type speakers are generally shielded (as are speakers intended for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Jim Conlin wrote: I'm very uneasy about speakers whose position or orientation is not fixed. They can seriously derange a magnetic compass. I'd much prefer that speakers be in a fixed location and orientation. None within several feet of the compass. "derbyrm" wrote in message news:F6lSf.31888$oL.11786@attbi_s71... Sorry, I lost the thread to a "view," but Radio Shack on-line has a $20 extension speaker http://www.radioshack.com/product/in...entPage=search For "waterproof," stick it in a big baggie. Roger http://home.insightbb.com/~derbyrm |
#5
posted to rec.boats.building
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speakers
The latter. Yes, a hand compass in the store would tell a lot.
Chuck Jim Conlin wrote: Is the function of the shielding to keep the speaker from picking up the RF noise from nearby electrical equipment or to contain the influence of the speaker's permanent magnet? Bring a hand compass to the store to test this. "chuck" wrote in message link.net... Marine-type speakers are generally shielded (as are speakers intended for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Jim Conlin wrote: I'm very uneasy about speakers whose position or orientation is not fixed. They can seriously derange a magnetic compass. I'd much prefer that speakers be in a fixed location and orientation. None within several feet of the compass. "derbyrm" wrote in message news:F6lSf.31888$oL.11786@attbi_s71... Sorry, I lost the thread to a "view," but Radio Shack on-line has a $20 extension speaker http://www.radioshack.com/product/in...entPage=search For "waterproof," stick it in a big baggie. Roger http://home.insightbb.com/~derbyrm |
#6
posted to rec.boats.building
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speakers
On Fri, 17 Mar 2006 14:44:53 GMT, chuck wrote:
Marine-type speakers are generally shielded (as are speakers intended for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Something I always wondered about is, "How do you magnetically shield something." Doesn't Magnetism pretty much go through things. How could you shield a speaker's magnet so it wouldn't affect a compass? Mark E. Williams |
#7
posted to rec.boats.building
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speakers
I missed that day in fre\shman physics, so i remain not informed but
concerned. A long time ago, i almost had a very nasty grounding because some speakers which had been brought on board deranged the compass. "Maynard G. Krebbs" wrote in message ... On Fri, 17 Mar 2006 14:44:53 GMT, chuck wrote: Marine-type speakers are generally shielded (as are speakers intended for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Something I always wondered about is, "How do you magnetically shield something." Doesn't Magnetism pretty much go through things. How could you shield a speaker's magnet so it wouldn't affect a compass? Mark E. Williams |
#8
posted to rec.boats.building
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speakers
FWIW, there are even nonmagnetic speakers, of which the piezo type are
unpleasantly common as beepers. Electrostatic speakers can be impressive, but are difficult to design. Not worth the expense for use with VHF radios. Chuck Maynard G. Krebbs wrote: On Fri, 17 Mar 2006 14:44:53 GMT, chuck wrote: Marine-type speakers are generally shielded (as are speakers intended for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Something I always wondered about is, "How do you magnetically shield something." Doesn't Magnetism pretty much go through things. How could you shield a speaker's magnet so it wouldn't affect a compass? Mark E. Williams |
#9
posted to rec.boats.building
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speakers
Swinging the vehicle to check the compass is a basic navigator duty. For
aircraft there's a compass rose on the tarmac, for boats/ships there are hand bearing compasses and pelorus (pelori??), but see http://www.boatsafe.com/nauticalknowhow/bearing.htm Check with all equipment on board and energized and the engine running (if applicable). A deviation card should be mounted on the compass, or close by. Speaker magnets are just one of many sources of deviation. Then again, there are really cheap hiking-type GPS units that will tell you your track (but not your heading). Roger http://home.insightbb.com/~derbyrm "Jim Conlin" wrote in message . .. I missed that day in fre\shman physics, so i remain not informed but concerned. A long time ago, i almost had a very nasty grounding because some speakers which had been brought on board deranged the compass. "Maynard G. Krebbs" wrote in message ... On Fri, 17 Mar 2006 14:44:53 GMT, chuck wrote: Marine-type speakers are generally shielded (as are speakers intended for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Something I always wondered about is, "How do you magnetically shield something." Doesn't Magnetism pretty much go through things. How could you shield a speaker's magnet so it wouldn't affect a compass? Mark E. Williams |
#10
posted to rec.boats.building
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speakers
My problem was that the speakers were moveable, as were the bracket mounted
speakers referenced in the first post. If the orientation or location of a permament magnet speaker can be easily changed, What's the navigator to do? "derbyrm" wrote in message news:rQUSf.829891$x96.477169@attbi_s72... Swinging the vehicle to check the compass is a basic navigator duty. For aircraft there's a compass rose on the tarmac, for boats/ships there are hand bearing compasses and pelorus (pelori??), but see http://www.boatsafe.com/nauticalknowhow/bearing.htm Check with all equipment on board and energized and the engine running (if applicable). A deviation card should be mounted on the compass, or close by. Speaker magnets are just one of many sources of deviation. Then again, there are really cheap hiking-type GPS units that will tell you your track (but not your heading). Roger http://home.insightbb.com/~derbyrm "Jim Conlin" wrote in message . .. I missed that day in fre\shman physics, so i remain not informed but concerned. A long time ago, i almost had a very nasty grounding because some speakers which had been brought on board deranged the compass. "Maynard G. Krebbs" wrote in message ... On Fri, 17 Mar 2006 14:44:53 GMT, chuck wrote: Marine-type speakers are generally shielded (as are speakers intended for use near CRTs) so this should not be a problem. The speaker description/packaging should indicate whether it is magnetically shielded. I'd be interested in hearing of any cases where a magnetically shielded speaker has interfered with magnetic compass readings. Chuck Something I always wondered about is, "How do you magnetically shield something." Doesn't Magnetism pretty much go through things. How could you shield a speaker's magnet so it wouldn't affect a compass? Mark E. Williams |
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