XTL5000 Seemingly Not Working on Talkgroup From Working Clone

[KE4ZNR]

I was a little bummed that the technician who performed the work was unavailable. As a result I did not get to review the report with him. Currently this is mostly gibberish to me, hopefully in the course of my studies I will learn how to properly read this report.

We have a few Aeroflex 3920s in my shop and I use them daily. The big thing is at the beginning of the report: The Reference Oscillator. Notice how it says "< 100Hz" meaning that you want your reference oscillator to be less than 100Hz off spec? Then the fact your radio was -924Hz off? That is waaaaay off. Notice right below that the Aeroflex pulled it back in to " -19Hz"? That is muuuuch better. Only 19Hz off verses 924Hz off is night and day difference. THAT is why the radio is performing so much better.
This is why the 3920 Test sets are worth their weight in gold.

 

[AM909]

Freq was the likely culprit. Deviation was a little high, as was power setting. This combination of issues are often found on radios that have been unprofessionally "tuned" with uncalibrated instruments. I've seen analog narrowband (2.5 kHz dev spec) 25W radios cranked up to 32W and 9 kHz deviation, probably intentionally, to make them "louder"!

 

[n3obl]

So just to reiterate most of these astro25 gear has been in service for a number of years that is hitting the surplus market and has not seen a service monitor ever. Hence why it’s always good to start out with a professional alignment.

 

[MTS2000des]

Not to mention, if one expects performance on P25 trunked or conventional, an alignment for a 10-20 year old radio that's seen years of hard service is as mandatory as fully servicing a well used car and expecting it to stay on the road.

 

[thisguyneedsabeer]

Not to mention, if one expects performance on P25 trunked or conventional, an alignment for a 10-20 year old radio that's seen years of hard service is as mandatory as fully servicing a well used car and expecting it to stay on the road.

For sure, lot's of lessons learned here, and I'm better prepared going forward into this wild and crazy world of amateur radio.

Now that this is working, I'd like to bring the whole project home with the O3 Display Mic. I "believe" this will be as simple as changing out the control head, with PMLN5038A, changing the control head in the software, and then programming via HKN6161B, and plugging in PMUN1034B

 

[Project25_MASTR]

We have a few Aeroflex 3920s in my shop and I use them daily. The big thing is at the beginning of the report: The Reference Oscillator. Notice how it says "< 100Hz" meaning that you want your reference oscillator to be less than 100Hz off spec? Then the fact your radio was -924Hz off? That is waaaaay off. Notice right below that the Aeroflex pulled it back in to " -19Hz"? That is muuuuch better. Only 19Hz off verses 924Hz off is night and day difference. THAT is why the radio is performing so much better.
This is why the 3920 Test sets are worth their weight in gold.

I would hope the 3920's can do better than that with Autotune and the 19 Hz error was due to the hardware limitation. My R8x00 tunes will all fail if there is more than 20 Hz of error after alignment (which is how I have them configured).

 

[KevinC]

And all this frequency error talk is useless unless they have a highly accurate frequency standard attached to the testing device. Such as a rubidium standard.

 

[Project25_MASTR]

And all this frequency error talk is useless unless they have a highly accurate frequency standard attached to the testing device. Such as a rubidium standard.

The 3920, 8800, CX300, R2600, R8x00's all have internal calibrated references. Though you can interface them to external standards such as a Rubidium or GPSDO they don't need it for testing radios per manufacturer specifications as long as your monitor is within it's calibration certificate (which my personal R2670 is not which is why I use a GPSDO and only work on my personal stuff with that monitor).

 

[KE4ZNR]

The 3920, 8800, CX300, R2600, R8x00's all have internal calibrated references. Though you can interface them to external standards such as a Rubidium or GPSDO they don't need it for testing radios per manufacturer specifications as long as your monitor is within it's calibration certificate (which my personal R2670 is not which is why I use a GPSDO and only work on my personal stuff with that monitor).

We have local shop that calibrates & certs our 3920s (Which we need to have done again at the beginning of this next year).

 

[AM909]

For hams or hobbyists without calibrated equipment, though, a decent (i.e. $30, not $20 ) SDR can be a good test instrument for frequency at least. Most higher-end trunk and paging systems will have GPSDO or some other high-quality reference and you can see a consensus for where your SDR is in relation to them by watching them over the air. Sure, it's another couple degrees of separation from a primary standard, but good enough in many cases. In my grab-and-go hobbyist bag, I've got a couple NooElec NESDR SMArt v5 that have different errors in the 2 ppm range, but hold within < 0.2 ppm after warming up for half an hour or less. I check against a good source and sticker them once in a while, and they've drifted a few tenths over a couple years. Beats lugging around a 30 pound, $40,000 monitor for some applications.