XTS3000 Alignment

Discussion on P25
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kc9uhi
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Joined: Mon Dec 02, 2013 10:46 pm

XTS3000 Alignment

Post by kc9uhi » Wed Apr 16, 2014 12:55 pm

Anyone have experience aligning a xts3000? I've got two of them that don't want to push out p25 at 144.590. I could trial & error adjust it all day, but could use some pointers.

I'm guessing the same procedure would fix up the two astro spectras I've got as well.

kb9mwr
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Joined: Tue Dec 03, 2013 10:59 am

Re: XTS3000 Alignment

Post by kb9mwr » Wed Apr 23, 2014 1:32 pm

My guess is that down that low in freq the radios are just do dirty (wave form) that P25 won't get decoded properly by another radio.

I am not sure what the cure would be. I really don't think the soft pot deviation adjustments would have much effect. It would likely be a hardware thing. Coil spreading or something like that.. I have not looked under the hood of a spectra.

But getting the analog deviation right is worth a try. I have no way of adjusting the digital mode stuff.
I poked around in the tuner menu. I can't figure out if there is a way to set a calibration freq on the high end of the band and one on the low. Seems you get what they have pre-programmed, 142.125 and 154.225 MHz straddle the ham band. On the gm300's you can define the freq.

The problem with soft pots are each radio is a bit different. So a relative value of one setting on one radio, isn't necessarily the same on another. I'll poke around with my saber later tonight to see what options the service menu give us.

Next time you are up give me a yell, we can set the analog deviation at the cave. That appears do be as much as we'd be able to do. The rest is trial and error, if it will even make an effect.

kc9uhi
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Re: XTS3000 Alignment

Post by kc9uhi » Wed Apr 23, 2014 5:26 pm

Apparently if the battery is getting low, rather than still transmitting, like most other motorola radios I've encountered, it'll just sit there and blink the status light. Won't transmit analog either. Dropped it on the charger, and it worked... for a bit. Apparently the batteries I got with the radios are shot. New batteries on the way. Hopefully that's all it needs.


Other related news:

While poking at an astro spectra the other day, I learned that the deviation softpot calibration frequencies are fixed, and frequencies inbetween are extrapolated. However, for frequencies below the band-edge in the radio (based on model number, editable in the S-Record) the radio doesn't know how to calculate properly. After dropping the lower band edge frequency in the S-Record a few megahertz (working with a K split radio, dropped from 146 to 143), and a bit of trial-and-error adjusting the lowest deviation softpot, I successfully got it to transmit decodable p25 at 144.59.

In short, with a S-Record mod and a bit of unconventional re-alignment, getting a K split astro radio to transmit p25 at lower than rated frequencies can be done.

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