# Police Radios



## vango57 (Mar 12, 2011)

Is there any value in the boards out of portable police radios?


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## glondor (Mar 12, 2011)

From what I understand, yes there is. Open one up and take a look.


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## alesswo (Mar 14, 2011)

I found a picture in ebay.http://cgi.ebay.com/FIND-GOLD-TODAY...072?pt=LH_DefaultDomain_0&hash=item35a554c238, they claim is solid gold, as per a read in the e-report they sell it comes from police radios: " This GOLD BAR was found in a Motorola Two-way police front mount radio, in the power amp section. It was used to reduce heat during transmission.", what do you know about it?


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## jimdoc (Mar 14, 2011)

I think a lot of police radios would be stolen if that was the case.

Jim


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## alesswo (Mar 15, 2011)

jimdoc said:


> I think a lot of police radios would be stolen if that was the case.
> 
> Jim


 :lol: :lol: that was what I am thinking.


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## Harold_V (Mar 16, 2011)

alesswo said:


> " This GOLD BAR was found in a Motorola Two-way police front mount radio, in the power amp section. It was used to reduce heat during transmission.", what do you know about it?


What do I think about it?
I think it makes no sense whatsoever. 

Silver is a better conductor of both heat and electricity than gold---and is worth one hell of a lot less-----yet they chose gold? Makes no sense. If it's not silver, there's no reason it should be gold. 

Harold


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## Ocean (Mar 16, 2011)

Harold_V said:


> alesswo said:
> 
> 
> > " This GOLD BAR was found in a Motorola Two-way police front mount radio, in the power amp section. It was used to reduce heat during transmission.", what do you know about it?
> ...



Harold, if Silver is a better conductor and is less expensive, why is it still used extensively in electronics.

Thanks for the info.

Ocean


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## goldenchild (Mar 16, 2011)

Ocean said:


> Harold, if Silver is a better conductor and is less expensive, why is it still used extensively in electronics.
> 
> Thanks for the info.
> 
> Ocean



If I may chime in here. The first thing that comes to mind when choosing to use gold opposed to silver in electronics is oxidation. Oxidized silver would create a poor electrical current.


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## rusty (Mar 16, 2011)

I'll take a stab at this,Gold is the most malleable and ductile of all metals, nano traces come to mind inside IC chips; Gold also makes for a good barrier from oxidation when plated onto pins and fingers,

Police radios are nothing special, just UHF or VHF radios using frequency's assigned to police work.


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## Harold_V (Mar 17, 2011)

goldenchild said:


> Ocean said:
> 
> 
> > Harold, if Silver is a better conductor and is less expensive, why is it still used extensively in electronics.
> ...


That's correct, but silver doesn't oxidize, it sulfates---which is the discoloration seen commonly on silver. Because gold does not oxidize, it is chosen as a protector for electronic circuits to insure that their is no resistance due to corrosion at electrical connecting points. Both silver and copper are better conductors of electricity, but neither have resistance to corrosion the way gold does. 

Harold


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## Harold_V (Mar 17, 2011)

Ocean said:


> Harold, if Silver is a better conductor and is less expensive, why is it still used extensively in electronics.


I expect your question isn't why is silver used extensively----but gold, instead. 


**Corrosion resistance. **

Harold


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## rusty (Mar 17, 2011)

Harold_V said:


> Ocean said:
> 
> 
> > Harold, if Silver is a better conductor and is less expensive, why is it still used extensively in electronics.
> ...



Here is an example of a modem card that somehow missed the gold plating on the fingers, as pulled from PC.


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## goldenchild (Mar 17, 2011)

rusty said:


> Harold_V said:
> 
> 
> > Ocean said:
> ...



Looks like wear and tear.


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## pesco (Mar 22, 2011)

Hi,
its my first post here, later on I will introduce myself in appropriate section 




Harold_V said:


> **Corrosion resistance. **
> 
> Harold




That is one of the reasons why gold is being used to plate connectors. The other and often overlooked and more important reason is *friction*. Gold on gold friction is *tiny*. Because of that it is much easier to operate multi pole gold plated connector then the tin/copper one. If both sides of a connectors are gold plated they are meant to smoothly "slide" on each other and as there is no oxidants on a surface it creates connection with very small resistance. In case the connectors are made of/plated with tin or copper during insertion the external skin of oxides meant to rub of allowing bare metal of both sides to touch each other creating connection with very small resistance. In fact cooper or tin connectors are forming better electrical connection. The tightness of such connection doesn't let oxygen to get in between surfaces, so even slightly higher temperature on the border between plug and socket surfaces doesn't lead to oxidation. *That happens when they are new*. Because of the rubbing action the wear and tear has much more significant impact on life of such connectors - they are being "sanded of" with each insertion and eventually the connection might not be as tight as it supposed to be letting tiny bits of oxygen to reach in between plug and socket. Sometimes only few in-out cycles is enough to allow oxygen to penetrate tin/copper connection.

Bottom line - gold plated ones are easier to operate and can withstand many more in-out cycles.


Regards


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## macfixer01 (Mar 27, 2011)

Hi,
I don't have any way to find it now but a few weeks back somebody auctioned on Ebay a couple pound bottle of some really nice gold circuit board contacts. He said they came from boards in remote heads of Motorola radios. I'm not sure if he said they were either Syntor or Micor models, and I think he was auctioning some boards too. They were little flat gold-plated oblong plates that stand up perpendicular to the board surface. They had a couple nibs where they were soldered into the board and a fork arrangement at the end where they made contact with some form of socket. They were pretty similar to these contacts I got off old 1970's CNC machine boards, but the Motorola contacts were a little different shape as I recall, more of a parallelogram I think.


macfixer01


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