125 watt VHF Quantar randomly drops TX

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KenHorse
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125 watt VHF Quantar randomly drops TX

Post by KenHorse »

Running with an external controller, interfaced via the Telco connector with Wireline card. It randomly drop TX even though external PTT is asserted by external controller. When PTT from controller drops, TX once again works.

I've been monitoring the repeater remotely (via CSS) and nothing looks out of the ordinary. SWR, forward power, voltages, etc. look good (well, except no RF out during these times)
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crazyboy
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Re: 125 watt VHF Quantar randomly drops TX

Post by crazyboy »

TOT?
KenHorse
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Re: 125 watt VHF Quantar randomly drops TX

Post by KenHorse »

I don't think so as it is disabled. And as I said, it happens totally at random, not based on any timer period
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N4DES
was KS4VT
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What radios do you own?: APX,XTS2500,XTL2500,XTL1500

Re: 125 watt VHF Quantar randomly drops TX

Post by N4DES »

Having the TOT to be controlled by the external controller is fine, but what I would try is to keep the TOT in the Quantar SCM and make for a time period that exceeds the external controller and see what happens. It just might not like being set to zero and is picking some random time period to time out.
KenHorse
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Re: 125 watt VHF Quantar randomly drops TX

Post by KenHorse »

Do you know what is the maximum value of the TOT or where can I find out? The HELP is not exactly chock full of info......

Edit: Nevermind. I see a mouseover in the CSS field says max is 2550 seconds.
Last edited by KenHorse on Sat Mar 09, 2024 4:00 pm, edited 1 time in total.
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Astro Spectra
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Re: 125 watt VHF Quantar randomly drops TX

Post by Astro Spectra »

When Quantars do random things it’s time to check the EEPROM in the SCM. Check if it’s the problem Xicor part or the good Atmel version.
Jim202
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Re: 125 watt VHF Quantar randomly drops TX

Post by Jim202 »

By any chance is the PA shutting down from high heat?
Jim
KenHorse
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Re: 125 watt VHF Quantar randomly drops TX

Post by KenHorse »

I don't think it's heat because the XMTR dies for the duration of hang time from the external controller. Once that happens, the TX is happy once more. Some times for hours
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