396XT and 346XT suddenly stopped receiving.

AJAT

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I had a 396XT connected to an external antenna that stopped receiving. Originally I figured the cable went bad, I took out my 346Xt and hooked it up to the external antenna and it worked just fine. About 4 days later it stoped receiving. I put the rubber duck antennas on them and tuned to the local weather frequency, which I should get with no problem, and both scanners are completely silent. Will not receive anything. The 396 has been working fine on the external antenna for about a year. Any thoughts on what could of happened?
 

hiegtx

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I had a 396XT connected to an external antenna that stopped receiving. Originally I figured the cable went bad, I took out my 346Xt and hooked it up to the external antenna and it worked just fine. About 4 days later it stoped receiving. I put the rubber duck antennas on them and tuned to the local weather frequency, which I should get with no problem, and both scanners are completely silent. Will not receive anything. The 396 has been working fine on the external antenna for about a year. Any thoughts on what could of happened?
For the highlighted text, did you mean it had been working fine on the external antenna, but no longer receiving anything?

Are there any other sources of transmissions near you, such as a broadcast or cell tower, or perhaps a nearby radio operator? From your description, it sounds as if the 396xt was working using the external antenna, then quit. And then, you connected the 346 to the antenna & it worked awhile, but it has since quit, and now neither one works, even using the original rubber duck antennas, even when tuned to the local weatherradio channel?

If there was a nearby radio, whether hand-held, or a base station, that transmitted along the times when these quit, the strong signal can damage the scanners so that they no longer receive anything. If, for example, one of your neighbors had called one of the local public safety departments, such as PD, Fire, & EMS, and a unit responded to the call, and made a transmission close enough with either their portable radio, or one in their vehicle, it's at least possible that would damage your scanner. Since these events (the individual scanners quitting operation) were several days apart, I'd be suspecting a fixed transmitter, not a portable. Were there any storms, with lightning, around the times these units quit? A nearby strike would also cause the same result, even if your house did not take a direct hit.
 

tvengr

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Are you using the same AC adapter for both scanners? You could be getting excessive DC voltage or AC voltage out of the power supply and that damaged both scanners. Did you recently change the power supply? You may be using a wrong supply. I would also check for voltage on the external antenna connector.
 
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tvengr

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Try using your scanners on battery power. The AC adapter could be outputting insufficient voltage or have high ripple content. Ti is also possible that the AC adapter has failed completely and the scanners ran on battery power until the batteries died. Also, please read previous post #3.
 
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AJAT

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For the highlighted text, did you mean it had been working fine on the external antenna, but no longer receiving anything?
Yes that is what I meant.
There were no other transmitters near by. I live in a rural area off a fort road. Not much public safety coming up this way. No new cell towers nearby, the closest one is a a about 5-10 miles out. Although we are in the monsoon season, it has not been to bad this year and no nearby lighting strikes.
 

AJAT

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Try using your scanners on battery power. The AC adapter could be outputting insufficient voltage or have high ripple content. Ti is also possible that the AC adapter has failed completely and the scanners ran on battery power until the batteries died. Also, please read previous post #3.
Tried them on batteries still silent. Yes it was the same power supply. I will check the power supply voltage later today. Thanks
 

donc13

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Your 346 has gone silent also? If both were working and now neither is working, I would strongly suspect your antenna cable is not properly grounded and lightning or static surges have blown the radio's front end.
 

AJAT

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The antenna is grounded to a ground with a 8 gauge wire, bonded to my electrical system ground with a 6 gauge. The coaxial goes to a lighting protector that is grounded to the electrical system ground. As far as I know it is grounded correctly.
 

smithken

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I don't know how hard it would be to reprogram your scanners but I would consider resetting them and see if they come back to life. On the 396 press and hold the 2, 9 and hold keys while you turn the scanner on. This will wipe out any programming on the scanner.
 

trentbob

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Your 346 has gone silent also? If both were working and now neither is working, I would strongly suspect your antenna cable is not properly grounded and lightning or static surges have blown the radio's front end.
I concur, no matter how carefully and attentively grounded to lightning strikes, if you were hit with a direct strike, it's nuclear. Lost your front end on both radios.
 

AJAT

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I don't know how hard it would be to reprogram your scanners but I would consider resetting them and see if they come back to life. On the 396 press and hold the 2, 9 and hold keys while you turn the scanner on. This will wipe out any programming on the scanner.
I tried that still nothing, took the 396 apart and did not see anything obvious. I just double checked my ground system and everything seems ok. I guess I will just have to write off those two scanners. They been great for me. I had them both when they first came out and have been luckily enough to live in places where they were still useful. I still have a Pro-106 to use in until I decide on a replacement.
 

AJAT

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Well I think there is something wrong with my ground. I had my pro 106 plugged in to the wall outlet. Antenna disconnected. From the center pin of the coax to outer part of the BNC connector on the scanner I had 40 VAC. I guess I have to triple check my ground. Something is screwy.
 

KevinC

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Well I think there is something wrong with my ground. I had my pro 106 plugged in to the wall outlet. Antenna disconnected. From the center pin of the coax to outer part of the BNC connector on the scanner I had 40 VAC. I guess I have to triple check my ground. Something is screwy.
Please do be careful. I know 40 v of AC is low voltage, but still. If you don’t know what you’re doing please engage an electrician.
 

KevinC

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I’m going to guess you have underground electrical service?
 

hiegtx

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I don't know how hard it would be to reprogram your scanners but I would consider resetting them and see if they come back to life. On the 396 press and hold the 2, 9 and hold keys while you turn the scanner on. This will wipe out any programming on the scanner.

I concur, no matter how carefully and attentively grounded to lightning strikes, if you were hit with a direct strike, it's nuclear. Lost your front end on both radios.
The Op said previously that there had not been any nearby lightning strikes. For that matter, static electricity might be an issue, but two events, several days apart, taking out the two scanners seems to be a stretch.

Well I think there is something wrong with my ground. I had my pro 106 plugged in to the wall outlet. Antenna disconnected. From the center pin of the coax to outer part of the BNC connector on the scanner I had 40 VAC. I guess I have to triple check my ground. Something is screwy.
Problems with the ground, and showing a voltage present between the conductor & shield, are very likely to have caused the issues. As Kevin noted, even though the apparent voltage (at this time) is low, it may well have been at a higher voltage during the period when the scanners quit working. Indeed, this is something that would warrant calling an electrician, rather than jeopardizing your own safety.

Looking at your county, it appears to be using conventional channels, not trunked systems. But P25 Phase II systems are heavily in use in other parts of your state, as well as metro areas across the country. It would cost you a little over $100 (counting shipping to Uniden) to get either unit repaired. You might be better off looking for an attractively priced previously owned scanner to replace at least one of these two radios.
 

AJAT

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The scanner has 40 volts straight to ground with the antenna totally out of the picture. All three of my scanners when plugged in are getting the 40VAC to ground. When I plug the antenna in the voltage goes away 0 volts to ground. The voltage is going to ground through the antenna ground.
 

KevinC

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No I am off the grid. I have solar only using the well pump casing as the main ground.
Ok. I’m not an electrician, but it sounds like you lost your neutral somewhere. Someone will correct me if I’m wrong.
 
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