Shorted GPS antenna caused XPR mobiles to transmit spurious signals

[RFguy]

Has anyone seen this. We had a XPR4550, VHF, 1-25 watt mobile that was transmitting spurious power throughout the 120-130 MHz band. Traces it down to a GPS antenna cable pinched/abraded such that it was shorted.

We thought it was a one off, but recreated it on other 4550 and 5550 mobiles. The 5550's weren't as bad. They displayed a synthesizer lock error, but still transmitted off frequency.

Anyone else seen this?

 

[RFI-EMI-GUY]

It sounds like the DC bias for the GPS preamp lacks any current limiting and the voltage is getting dragged down. The same voltage must have commonality with the synthesizer. Potentially a very bad design desision by Motorola.

 

[Mars]

Has anyone done Motorola the courtesy of notifying them?

 

[techman]

Why? North America office and dhs read the forum just don't contribute a lot! Maybe they can chime in and give a reference number for this issue,


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[mss-dave]

Why? North America office and dhs read the forum just don't contribute a lot! Maybe they can chime in and give a reference number for this issue,


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Well, they can't because their whole ip subnet is blocked I believe. At least Motorola's is....

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[Gtaman]

Well, they can't because their whole ip subnet is blocked I believe. At least Motorola's is....

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Someone has to read this forum over cellular.

 

[Mars]

Well, they can't because their whole ip subnet is blocked I believe. At least Motorola's is....

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Yes, that's true. This is the error they receive:

http://msi.communications.support

I'm not unblocking them until they resolve matters.