Radio interference from ISY-994i?

[K3RMB]

I have been using my ISY-994i for several years now with no problems.

 

I am also a ham radio operator. Recently, I began experiencing a strong radio signal at approximately 146.64 Mhz. This signal is strong enough that the it overpowers (makes it impossible to hear) my club's repeater, whose output is at that frequency.

 

Using direction finding techniques, it was determined that the interference is coming from my ISY-994i. Plugging the device out results in the elimination of the offending signal.

 

Any suggestions as to why the interference and how this issue might be resolved?  

[G W]

Is it the ISY, the PLM or the ISY power supply?

 

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[K3RMB]

Think it's the ISY.  I turn the power off by plugging the power cable out of that device.  The power supply and PLM are still in their outlets and powered on.

[Techman]

I have been using my ISY-994i for several years now with no problems.

 

I am also a ham radio operator. Recently, I began experiencing a strong radio signal at approximately 146.64 Mhz. This signal is strong enough that the it overpowers (makes it impossible to hear) my club's repeater, whose output is at that frequency.

 

Using direction finding techniques, it was determined that the interference is coming from my ISY-994i. Plugging the device out results in the elimination of the offending signal.

 

Any suggestions as to why the interference and how this issue might be resolved?  

 

K3RMB

 

I have my ISY sitting within 10 inches from a 2 meter radio. I don't hear any signal in the 146 Mhz range coming from the ISY. 

You may have either a bad piece of coax, or a bad Ethernet cable connected to the ISY.

[G W]

When you get time, unplug only the PLM from the power outlet and see if there is any change in the noise.

 

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[Teken]

I would believe the PSU as the primary culprit over the ISY Series Controller. Replace it and see what happens.

 

The two most common failure and when I say common it's not very common. But the 3rd party PSU and Micro SD Card which neither UDI makes.

 

 

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[stusviews]

That's a new one on me. If nothing else helps, a Faraday cage (copper screen) should be easy enough to build. Just wrap the ISY or create something more elaborate

[lbiffle]

If you have any ferrite cores, try looping the cables through them as many times as you can, and see if that kills/reduces the signal. I’ve had switching power supplies that generated birdies a long way up the spectrum, though not up to 2 meters.

 

My ISYs don’t produce noise up there, but they’re not very current in firmware. Good luck.

 

 

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[larryllix]

I would believe the PSU as the primary culprit over the ISY Series Controller. Replace it and see what happens.

 

The two most common failure and when I say common it's not very common. But the 3rd party PSU and Micro SD Card which neither UDI makes.

 

 

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And it shouldn't be forgotten that PSU may be quiet when the ISY load is removed.

 

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