VHF QUANTAR TX and RX tuning

dtbuff88

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Does anyone have a step by step guide to tune the receiver and exciter on the VHF Quantar. Or can you point out where its at in the service manual?
 

Bill_G

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You use the RSS and a service monitor. Got those?
 

Bill_G

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yes indeed. Aeroflex 8800

There isn't a lot to tune. You can adjust the freq, xmit power, and dev with the RSS. There are no (soft) rcvr adjustments - just setting the physical coils in the front end band pass filter. There are some other (soft) adjustments points for wireline, and dev linearity, but most amateur applications don't require it.
 
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dtbuff88

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ok, On my MASTR III i had to add to the slugs. I didn't know if I would have to do something on the quantar as well.
 

CARC383

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On the VHF Quantar there are five tuning slugs sticking out the front of the receiver. There is a specific procedure for those and I have gone through that but I have also just peaked them all for best SINAD and came out with the same resulting sensitivity. Its best to follow the factory procedure but in a pinch you can just tune for maximum smoke. Otherwise go through RSS as others have mentioned setting dev, squelch, frequency, etc.
ok, On my MASTR III i had to add to the slugs. I didn't know if I would have to do something on the quantar as well.
 

d119

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I have also just peaked them all for best SINAD and came out with the same resulting sensitivity.
That has always been the way I do the Quantar front end. I've never had a problem doing it that way. You can screw with that probe all you want, but you'll come out with the same results.
 

CARC383

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That has always been the way I do the Quantar front end. I've never had a problem doing it that way. You can screw with that probe all you want, but you'll come out with the same results.
The probe is good if your changing the tuning from one extreme end of the band to the other.
 
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dtbuff88

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As it sits right now the rx fail led is blinking. I will keep working with it and see what I can come up with. It did go from 155 down to 145mhz.
 

CARC383

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As it sits right now the rx fail led is blinking. I will keep working with it and see what I can come up with. It did go from 155 down to 145mhz.
If its a range 2 receiver many won't make it to 145Mhz. Try programming 146 then 147 or 148MHz to map out where it goes out of lock.
 
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dtbuff88

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You are correct. I got it to work! I seen now where it says 146 is about the bottom of the barrel .
 

CARC383

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You are correct. I got it to work! I seen now where it says 146 is about the bottom of the barrel .
There should be a way to tweak a part on the exciter board to extend the transmit lock range slightly. I don't have the specific info but maybe someone else on this forum does. If you can get it to lock, the tuning slugs should cover down to 145MHz or at lest the one's I've played with will.
 

wiredwrx

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Check out W9CRs wiki regarding the Quantar. There is TONS of info there. https://wiki.w9cr.net/index.php/Quantar I will add that I normally tune the Quantar reciever filters with a tracking generator. I have never tuned a VHF with the 5 slugs, but the UHF with 3 is relatively easy to tune with a TG.
 

SwissMoto

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The problem with R2 Quantars on 145 MHz is that the VCO won't lock
Locate L2202 on the VCO unit and give it 2-3 turns clockwise. After that the VCO will lock across the entire 145-148 MHz VHF HAM band.
See attached diagrams.
 

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  • Quantar 02 m RX VCO for 145 MHz-3.jpg
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  • Quantar 02 m RX VCO for 145 MHz-4.jpg
    Quantar 02 m RX VCO for 145 MHz-4.jpg
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