Radio Maintenance

[Radio147]

Hi,

We are somewhat new to the digital radio arena, switched to run on APX in the last year or so. We were on analog before. Previously, our maintenance was basically when a radio breaks, we send it to the shop to fix. We heard that digital radio is more sensitive than analog and Motorola recommend yearly maintenance. In particular, they recommend aligning the reference oscillator at least once a year. From your experience running on APX series radio, is yearly maintenance something you actually performed?

Thanks.

 

[KE4ZNR]

Hi,

We are somewhat new to the digital radio arena, switched to run on APX in the last year or so. We were on analog before. Previously, our maintenance was basically when a radio breaks, we send it to the shop to fix. We heard that digital radio is more sensitive than analog and Motorola recommend yearly maintenance. In particular, they recommend aligning the reference oscillator at least once a year. From your experience running on APX series radio, is yearly maintenance something you actually performed?

Thanks.

Keeping the reference oscillator (as well as other values) on spec is VERY important when it comes to P25. We try to get all public safety radios through our shop for an alignment on our Aeroflex 3920s at least twice a year. We also use DiagnostX at all 4 of our tower sites to help us find trouble radios before they are scheduled to be brought in.
If a radio drifts far enough off spec there is a good chance it might not even affiliate onto a radio system.
You hopefully would not let your car wheels/tires drift out of alignment so the same should be applied to your radio.

 

[AM909]

I don't have much APX experience, but generally, modern commercial/PS radios seem to stay on channel and modulation spec pretty well, especially after the first year. I would say it's more about tightening loose hardware, fixing/replacing damaged case parts/knobs/antennas, etc. Some things are a lot cheaper/easier to fix if caught early. Definitely worth doing.

 

[speedway_navigator]

We also use DiagnostX at all 4 of our tower sites to help us find trouble radios before they are scheduled to be brought in.

Do you find radios during your PM that this system missed? Any common traits among radios that drift like sequential serial numbers that might indicate a crappy batch of components during that production run?
Do you test radios when you get them to verify they meet spec?

 

[ElroyJetson]

Yes, it's standard practice to yearly PM all radios on trunking systems. And you should.

 

[KE4ZNR]

Do you find radios during your PM that this system missed? Any common traits among radios that drift like sequential serial numbers that might indicate a crappy batch of components during that production run?
Do you test radios when you get them to verify they meet spec?

1) Rarely. DiagnostX usually gets the majority of the offenders. It also keeps us on our toes as far as PMs.
2) We have been using APX radios since around 2017. No real common threads that we have been able to find other than some
6500s have their reference oscillators outside of tolerance straight out the factory box. We align every public safety mobile and
portable before being assigned/installed/reassigned/reinstalled.
3) See above. We test & align every radio that comes through our shop. We are blessed in that we have several 3920s so that there
is always at least one free for testing/aligning.

 

[PACNWDude]

When I worked in the oil and gas industry, we had a yearly maintenance schedule for all assigned radios.....this found many that were drifting from factory specification. This included the then new APX4000 and APX900 series radios. We had a dozen Aeroflex 3500 series test sets, much more portable than the 3920 series, but lots of accessories and adapters were needed for real world use. That was also with about 50-60 technicians spread across the country.

Now, my current employer has a dozen Aeroflex 3920 test sets that are no longer supported after 12 years of use....adding in Astronics R8200's. We also run a DiagnostiX unit, that has been moved between sites a few times.

While I have yet to see handheld radios out of spec from Motorola, some that have been dropped have needed tuning afterward. Mobile fail better being in vehicles, but still get accused of parasitic drain on the vehicles electrical system (often corresponding with the addition of other equipment - K-9 Units and their heaters/fans for the dogs), or when a vehicle is jump started.

There are now seven techs, and many radios do not get looked at every year. Just when there is a complaint, or issues reported. Some sites do not issue radios to a specific person, which makes is even worse, one user may say the radio works fine, but the next says the audio is too quiet, mic to sensitive, or speaker too loud (different audio profiles in some case, and others just different users voices).

I wish there was a yearly requirement, where I am now. Only simulcast sites get that treatment now.

 

[speedway_navigator]

Thanks for the detailed info, hope you survived the north easter which came from the south east.

I think yearly xmtr testing was an FCC rule when I started in the 80s, some of our service contracts with govt agencies required us to submit proof for CYA purposes. I bet Fred Daniels can fill us in, he's a wealth of knowledge.

or when a vehicle is jump started.

I remember being told to always pull the fuse for the TR pack as we called it before jumping a battery. GE had a plastic case with the fuse in the lid, that made it very easy to pull.