Uniden UM415 VHF Mystery Static

Rick D

Rick D

.
Jun 14, 2008
7,182
Hunter Legend 40.5 Shoreline Marina Long Beach CA
So, I have a Uniden back-up VHF at the chart table. Somewhere between five and seven years old. So, when the water pumps, we get static from the radio...even if it is off. When the inverter / charger is charging, we get static when it is off also. When I shut the switch off at the switch panel, no static. The unit sends and receives well via an antenna mounted on the stern radar pole. I also have a HAM radio that shares the same paths and is one switch down on the panel. It has no issue. Hardly a big deal, but curious if anyone has any suggestion why the unit will emit static under these conditions even when switched off? BTW, I have another VHF in the cockpit, but no power or antenna paths shared.
 
shemandr

shemandr

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Jan 1, 2006
7,477
Slickcraft 26 Sailfish
Once ham radio is mentioned, I'm out!
But hopefully my post will bring the OP to the top of the list and someone who knows radio can answer.
 
Don S/V ILLusion

Don S/V ILLusion

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Sep 25, 2008
7,346
Alden 50 Sarasota, Florida
Which Uniden radio?
some have powered speakers (audio amp) which isn’t switched.
Id put a voltmeter to the back of the radio to confirm no power
 
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E

east coaster

.
Apr 10, 2010
106
Catalina 310 166 Dartmouth, Nova Scotia
Nigel Calder has a lot of info and remedial measures to take in cases like this. Lack of shielded cables, close proximity of cables, loose connections, etc. Use of capacitors, rerouting of cables and ferrite clamps on cables are some cures. Best to refer to his 4th edition electrical/mechanical book for details and procedures for finding the cause. In my own case the only static I get is from the admiral when we are out of cell phone range or ice cubes.
 
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dLj

dLj

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Mar 23, 2017
4,282
Belliure 41 Back in the Chesapeake
Does it have an external speaker? If so, it may not be the radio but rather the wiring to the external speaker ( if you have one).

dj
 
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Rick D

Rick D

.
Jun 14, 2008
7,182
Hunter Legend 40.5 Shoreline Marina Long Beach CA
dLj said:
Does it have an external speaker? If so, it may not be the radio but rather the wiring to the external speaker ( if you have one).

dj
Click to expand
Don't have on this radio.
 
Mark Maulden

Mark Maulden

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Jan 25, 2011
2,436
S2 11.0A Anacortes, WA
Rick D said:
So, I have a Uniden back-up VHF at the chart table. Somewhere between five and seven years old. So, when the water pumps, we get static from the radio...even if it is off. When the inverter / charger is charging, we get static when it is off also. When I shut the switch off at the switch panel, no static. The unit sends and receives well via an antenna mounted on the stern radar pole. I also have a HAM radio that shares the same paths and is one switch down on the panel. It has no issue. Hardly a big deal, but curious if anyone has any suggestion why the unit will emit static under these conditions even when switched off? BTW, I have another VHF in the cockpit, but no power or antenna paths shared.
Click to expand
When troubleshooting EMI issues you need to establish the true source(s). If you physically disconnect the power to the pump, does it still occur? What switch is shut off at the panel? Can you turn off the charger at the charger? Also disconnect the antenna from the Uniden and see if problem persists. Power the Uniden directly to the battery with a separate wire and see if problem persists. This can tell you the coupling path.
 
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L

LloydB

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Jan 15, 2006
927
Macgregor 22 Silverton
When your portable radio is in battery charger mode it is turned on to charging mode but not transmit receive mode. Your boat is infested with gremlin. They will try to get out through the speaker if you let them.
 
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