micor mobile PA problem
Moderator: Queue Moderator
micor mobile PA problem
I have a micor mobile that has been split and put in 2 separate boxes. 1 transmit and 1 receive. It is set up as a repeater. The transmit is getting power to the exciter, because when you key it it with a HT it will ID and you can here the courtesy tone. Put a meter on it and showing no power out. Won't even move the needle. From what I've read if the finals are gone it messy. New at the repeater stuff and help will be appreciated. Thanks AG4TI
Re: micor mobile PA problem
Your getting into an area where you have to tread carefully. In
a normal mobile, there is a TX/RX relay to switch the antenna
back and forth. Once you split the operation, this normally
goes away.
I would look at the TX output cabling and see just how it
was routed. In a repeater operation, you should come off
the TX chassis from the output of the PA and go directly into
a coax cable to the duplexer. Check this out and see if that
is where your problem might be.
Jim
a normal mobile, there is a TX/RX relay to switch the antenna
back and forth. Once you split the operation, this normally
goes away.
I would look at the TX output cabling and see just how it
was routed. In a repeater operation, you should come off
the TX chassis from the output of the PA and go directly into
a coax cable to the duplexer. Check this out and see if that
is where your problem might be.
Jim
witurac wrote:I have a micor mobile that has been split and put in 2 separate boxes. 1 transmit and 1 receive. It is set up as a repeater. The transmit is getting power to the exciter, because when you key it it with a HT it will ID and you can here the courtesy tone. Put a meter on it and showing no power out. Won't even move the needle. From what I've read if the finals are gone it messy. New at the repeater stuff and help will be appreciated. Thanks AG4TI
-
jackhackett
- Posts: 1518
- Joined: Tue Jun 10, 2003 8:52 am
-
George
- Posts: 266
- Joined: Wed Apr 16, 2003 11:14 am
- What radios do you own?: X9000, HT1550XLS, MTS2000, etc
Here we go again!
Another perfectly good mobile that is on its way to being more dumpster fodder.
If you are going to build a repeater, build it out of repeater parts, not mobile parts. There are plenty of micor base stations out there that can be had for little or nothing that will save you SO MUCH work by not having to reinvent the wheel.
I have a perfectly good 60 watt micor base station that can become a repeater with the addition of a squelch gate card and if you ask nicely I'll even throw one in with a set of manuals. It's in a 42" cabinet with power supply and everything ready to convert and crystal. I'll even throw in channel elements if I have a transmit one for it. All this, and a lot of good experience you will gain will cost only $300.00 plus shipping.
When following the manual, assuming that most hams don't bother to read the manual, the conversion is fairly simple and straight forward. While the power amp is a 60 watt 150-162 range, I have run several in the 146 and 145 range and have yet to have one toast itself. I cannot say the same for the 100 watt continous duty version when taken out of band.
Please consider this offer as one for spectrum purity, saving yourself a huge pile of headaches and having something that is serviceable when it's finished rather than a cobbled up mess loaded with good intentions and bad engineering.
While some (most) may consider this to be inflamitory, so be it, but I would rather say something and make an offer for a real station than to have you go through the pain of making the same mistakes so many have made only to end up buying the real thing in the end. (and being able to sleep at night)
Yes, I have been quiet for a long time, but this mobile to repeater stuff really gets me going.
George
Another perfectly good mobile that is on its way to being more dumpster fodder.
If you are going to build a repeater, build it out of repeater parts, not mobile parts. There are plenty of micor base stations out there that can be had for little or nothing that will save you SO MUCH work by not having to reinvent the wheel.
I have a perfectly good 60 watt micor base station that can become a repeater with the addition of a squelch gate card and if you ask nicely I'll even throw one in with a set of manuals. It's in a 42" cabinet with power supply and everything ready to convert and crystal. I'll even throw in channel elements if I have a transmit one for it. All this, and a lot of good experience you will gain will cost only $300.00 plus shipping.
When following the manual, assuming that most hams don't bother to read the manual, the conversion is fairly simple and straight forward. While the power amp is a 60 watt 150-162 range, I have run several in the 146 and 145 range and have yet to have one toast itself. I cannot say the same for the 100 watt continous duty version when taken out of band.
Please consider this offer as one for spectrum purity, saving yourself a huge pile of headaches and having something that is serviceable when it's finished rather than a cobbled up mess loaded with good intentions and bad engineering.
While some (most) may consider this to be inflamitory, so be it, but I would rather say something and make an offer for a real station than to have you go through the pain of making the same mistakes so many have made only to end up buying the real thing in the end. (and being able to sleep at night)
Yes, I have been quiet for a long time, but this mobile to repeater stuff really gets me going.
George
-
jackhackett
- Posts: 1518
- Joined: Tue Jun 10, 2003 8:52 am
First thing I would check is the power control circuit, see if you're getting voltage to the first stage of the PA, should be something like 5-8 volts on the collector if I recall correctly.
I believe the high band PAs used PNP transistors, in which case the polarities are all reversed, collectors are negative with respect to the emitters (circuit board common is at +12v)
I believe the high band PAs used PNP transistors, in which case the polarities are all reversed, collectors are negative with respect to the emitters (circuit board common is at +12v)
-
RADIOMAN2002
- Posts: 1102
- Joined: Thu Apr 04, 2002 4:00 pm
- What radios do you own?: More than I can count