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VXR-1000 Vehicular Repeater Problem

Posted: Thu Dec 20, 2007 12:33 pm
by Jack
I have a VXR-1000 installed in my patrol car. Whenever I try to use it, I find that transmissions received from my mobile to my portable are intermittent, meaning they cut in and out. On the mobile radio inside the car, there is no problem. This only happens when going through the VXR.

When I transmit on the portable, the comm center can hear me no problem, and nothing is intermittent on their end from me.

I have checked the cable connections, there is no issue. I have checked the power and antenna connections, all are good. I have watched the "MBL" light stay on while a signal is received yet the repeater is transmitting intermittently.

I have run into this problem before with some of my ham radio gear where incoming CTCSS is different than the tone transmitted. The crossband repeat function would always freak out. The only way to get rid of this was to "de-program" the radio and remove the incoming CTCSS decoding. Once I did that, everything was fine.

I'm curious if anyone here has seen this before and if so, what was the solution?

Re: VXR-1000 Vehicular Repeater Problem

Posted: Thu Dec 20, 2007 2:03 pm
by HumHead
What do you mean when you say that the repeated signal is "intermittant"? Is it a regular timed brief dropout, approximately every couple of seconds, or something more irregular?

On many vehicular repeaters, when repeating, the repeater drops its transmission and goes into RX mode briefly, usually every two seconds, to see if the user is transmittig on their portable. This is done as a safety feature so that the user can interrupt a transmission (or stuck carrier) to call for help in an emergency.

The feature can usually be disabled, at least on the Pyramid SVR200 series that I usually deal with, if the dropouts are a problem, but you have to weigh that against the safety of being able to call for help.

Re: VXR-1000 Vehicular Repeater Problem

Posted: Thu Dec 20, 2007 3:01 pm
by Jack
On the PAC-RT units we had with the syntor x9000's, it was that way and it worked out fine because the sampling was so quick. These units aren't setup to do that. The received signal from the repeater to the portable is definitely irregular. sometimes it won't do it at all but leaving it on repeat for any length of time, and the problem will start.

Re: VXR-1000 Vehicular Repeater Problem

Posted: Thu Dec 27, 2007 9:21 am
by transistor747
Are you in-band or operating on two different bands?
If your mobile radio and the portable are in the same band, you may well be suffering from desense. The VXR1000 transmitter interfering with the mobile receiver.

Another possibility is the VXR1000 transmitter is over modulating.