Polarities

Status
Not open for further replies.

dispatcher812

Member
Joined
Aug 8, 2009
Messages
512
Location
Connecticut
I have two Undien scanners, a 796D and a 350A. Currently the 796 is being used for a Railroad feed here.
The 350 has a marking like this: Positive polarity:

UK Power Supply Voltage and Polarity - Stagebeat

The 796 has the same marking however the the + sign is on the other side. It is the same symbol only shown differently. The + goes into an open middle. Are they the same? I want to put the 350 in my truck instead of the 796 for now. I know nothing when it comes to electronics. Sorry for the vague description. Kevin
 

WA0CBW

Member
Joined
Dec 8, 2011
Messages
1,387
Location
Shawnee Kansas (Kansas City)
Some radios require the center pin to be positive and the outer ring to be negative. Some are just the opposite. The outside ring is positive and the center pin is negative. From your description it sounds like you have one of each. THEY ARE NOT INTERCHANGABLE!

Be careful when using the one with the outer ring positive in a mobile application. Touching the outer ring to anything grounded (chassis etc.) or the outer ring of the antenna cable that is grounded will cause a short blowing a fuse somewhere.

BB
 

angelofwar

Member
Joined
Feb 11, 2012
Messages
47
Do a search on wikipedia for "Tip negative" or "Tip positive"...that'll give you the run-down, and prevent you from messing things up.
 

jackj

Member
Joined
Jul 19, 2007
Messages
1,548
Location
NW Ohio
If you look at the coaxial power connector on your scanner, it consists of the center pin and a wiper that contacts the outer barrel of the connector. If the line from the + symbol goes to the center pin then you attach the positive voltage to the hollow contact on the plug and the negative to the outer shell. If the center pin is labeled with the negative ( - ) symbol the pin takes negative voltage.

If you have any doubts about how to hook them up then hire someone to do the work for you. Hooking them up backwards will cause some SERIOUS damage to the scanner.
 
Status
Not open for further replies.
Top