Most common failed AutoTune/Autotest tests APX and TRBO

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PSEhub

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I was curious what others have experienced to be the most commonly failed tests on Aeroflex and Freedom test sets for APX and TRBO radios.

It seems nearly every radio fails TX power, most notably on the higher 700 and 800 frequencies near the upper band limits.
 

hoser

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Three musts for ports:

  1. Use a regulated power supply and the battery adapter. A pooched battery can fail a units HI_PWR test.
  2. Use only short [low loss], frequency capable cables, minimal connectors/adapters, and calibrate the cable in the service monitor as per mfgr procedures
  3. Make sure (test set) unit has latest firmware
 
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Three musts for ports:

  1. Use a regulated power supply and the battery adapter. A pooched battery can fail a units HI_PWR test.
  2. Use only short [low loss], frequency capable cables, minimal connectors/adapters, and calibrate the cable in the service monitor as per mfgr procedures
  3. Make sure (test set) unit has latest firmware

I have had a lot of issues with voltage drop on the Motorola battery eliminators. The new Trbo battery eliminators (XPR3K/7K, and ATEX) (with exception of XPR6K, CP200d and SL) feature nice thick 14 awg cable. The SL and CP200d use 22 awg.

We are using HP power supplies with the remote sensing leads, so the voltage is very precise.

On the 66009254001 APX portable battery eliminator however, they use a single pair of 22 awg wire with a length of 5+ feet. Therefore if you put in an exact 7.5V as measured on the contacts with no load, the high power tests will fail.

On lots of portables if you use the 66009254001 with 7.5V, you will actually receive an intermittent low battery warning on the radio.

I ended up making a table of difference calculated voltage drops and voltages for each battery eliminator, but it is frustrating that they don't use thicker cable on all of them. I may trim the leads and add thicker awg.

We use the Megaphase RF Orange cables and do the cable sweeps/loss calibration on both the Freedom and Aeroflex units. We use an N male to N male reference cable, and an N Male to BNC Male test cable for the freedoms (TNC for the 3920). This way the N to BNC adapter gets 1 for 1 swapped with an N female to N female barrel during the cable loss calibration.

The Freedom says to use a 6db pad for this process, not sure why.



Freedom only recently added the cable sweep multi point functionality comparable to Aeroflex in release 3.7 I believe. We are using 3.8.

There are some serious bugs with the cable sweep feature when switching between presets (becomes deselected, can't be reselected), however for test sets that are doing Autotunes 99% of the time and not using presets its workable.
 

Mars

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When I was at Bearcum, I noted the techs were not utilizing (during autotune on the R8000C) any means of measuring inline current while doing PA Bias adjustments on the mobiles or XPR repeaters. It's not possible to align that without measuring current. Quite often, the RF power output (especially the higher levels) would fail. This was because PA Bias wasn't calibrated/set properly before attempting power output calibration.

I prefer to do manual alignments (takes quite a while) but the cable I made up for my Agilent DVOM is 12-gauge, with a break in the positive lead that runs to my ammeter with a couple of feet of 14-gauge test lead cable. 14 gauge stranded is rated at 85% solid, so it's good for 12.75A. That's more than adequate. After I do the PA bias adjustment/write value, I exit out of tuner and connect the radio directly to the PS for the rest of the alignment process to ensure any potential voltage drop has no impact. So far, so good.

Loosely related: For anyone doing manual alignments with TRBO: TRBO Tuner has lots of good alignment/process info in the HELP section. It has all the values you need to know for doing the PA Bias, RX Front End Gain Attenuation + front end adjustment, etc. RTFM!
 

phantom

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+1 for cable calibration. A 0.5db cable loss that goes unattributed is enough to fail an otherwise valid radio in 7/800.
 

moetorola

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we built are own eliminators with 12 awg x4feet wire, not paying for those overpriced adapters with 18awg wire 300feet long.

When we do have a failure on auto test it is normally (freedom) the APX portable for the squeal feed back test bull crap..LOL

Usually when a TX power fails, it is actually failed and not false negative. (using swept cable with loss entered)
 
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PSEhub

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Of the portables that haven't been alligned in 5+ years, what approximate percentage would you say fail at least some TX power tests?

Also, how critical is the 7.5V vs ~7.65V? Motorola doesn't take it very serisously with their $175+ 5 feet of 22awg

we built are own eliminators with 12 awg x4feet wire, not paying for those overpriced adapters with 18awg wire 300feet long.

When we do have a failure on auto test it is normally (freedom) the APX portable for the squeal feed back test bull crap..LOL

Usually when a TX power fails, it is actually failed and not false negative. (using swept cable with loss entered)
 

moetorola

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All of ours get touched every 5 years or so for fleet change or various updates. So I can give a ruff number for that.

For XTS series we had 1 out of 10 fail TX tests. (severe TX failures) 500mw or less. Our system is very balanced, has really good ears. Many users with radio's that failed to pass, they did not even know their radio had an issue.

For APX, I have not had any failures yet. Unless you count the brand new pre-deployment radio failures that had to be sent back. Most of those that failed could be tuned back to passing, however.

FWIW, as of late (2019~2020), I have not had any APX's they did not pass pre-deployment just fine. Maybe the complaints got back to SmallM.

Also we have changed our monitor/s failure thresholds to much tighter specs than what is standard specs. The reason, because the monitor will keep tuning until it hits the set value. If it fails, we look thru the log and see if it was with in Moto spec at-least.
 
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PSEhub

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It sounds like my sampling is a bit different, ~70% of crusty XPR6550s and brand new in box XPR7550e are failing tx power just barely, and not across the whole band.

The APX in question are 7K and AN 6000 Li mostly, most of which were NOT tested before being put into service, so its hard to say if they would have failed out of box, but its still a good 7/10, failing high power test on only some of the freq test points.


Would appreciate any feedback on the precision/importance of the 7.5V
 
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