[ARC5] [ARC-5radio] ARC-5 cable connectors question

[Brian Clarke]

Lets be careful about 'old wives tale debunked'.

When there is absolutely no possible change of position of the wires in use, 
eg, no vibration, and absolutely no possibility of temperature change, eg, 
heating changes caused by variations in current flow, then soldering without 
wrapping is acceptable. But solder's resistivity is around nine times higher 
than that of copper. Where you don't want high resistance points in circuits 
where there is current change, or where there is vibration, then wrapping 
the wire around the terminal is the 'high reliability' solution found in 
most military service manuals.

Wire wrapping and then soldering is the method used in all Command 
components, probably because of the inherent vibration is military 
applications. Also, have a look in any of the recent IPC standards.

60:40 solder, while melting at a slightly higher temperature than the 
eutectic mix of 63:37, has a plastic temperature range that can absorb 
slight movement during cooling without causing fracture or air inclusions. 
63:37 solder has no plastic phase - it goes straight from liquidus phase to 
solidus phase. For the wire used in Command connectors that carry heavy DC 
current, 60:40 is the preferred solder.

73 de Brian, VK2GCE

On Sunday, December 15, 2013 6:28 AM, Mike Hanz said:


> You don't, John.  They are insert, heat, solder, which is pretty much how 
> all connectors are put together.  It helps to have one of those weights 
> with the adjustable test clips on them to hold each wire as you solder it 
> into the cup and a vise for the connecter.  If there are no wires soldered 
> in the two used cups you can use the heat and stab method.  It's odd, but 
> connectors were probably the first instantiation of the "solder is strong 
> enough" philosophy that found its culmination in the Tektronix scopes, 
> where _nothing_ was wrapped around terminals "to make a secure mechanical 
> connection".  Another old wives tale debunked.
>
>           73,
>  - Mike  KC4TOS