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PL DECODE ON ASTRO SABER
Posted: Wed Mar 11, 2009 3:06 pm
by N4KVE
Hello. I have a bunch of UHF Astro Sabers that I use on ham repeaters in analog. Most are AS1's but 1 is an AS3.They work great on all repeaters except for 2 radios on 1 specific repeater. On these 2 radios they both tx into the repeater fine on pl 127.3, but one of them won't decode at all on that same pl, & the other radio takes a second for the pl to decode. Will a radio alignment fix this, or should I ask the repeater owner to check his equipment? For now I have left these 2 radios in open rx on this freq & they work fine. These 2 radios decode just fine on all other freq's. Otherwise these 2 radios are perfect. The other 6 or so radios decode just fine on this repeater. Thanks for any help. GARY N4KVE
Re: PL DECODE ON ASTRO SABER
Posted: Thu Mar 12, 2009 11:18 am
by Pj
Moved to the ASTRO fourm.....
It could be a combo of both. The Motorola radios are very tight on PL's, as they built very well. Many ham machines, tend not to be and the devaition is typically way off. This is not usually noticed by the average ham community as their radios (if they even have PL decode enabled) tend to devate quite a bit as well.
That being said, the one radio you have that does unmute on the PL may need to be aligned if its opening up with a wide devation. A very quick test you can perform with your two suspect radios is to check the squelch level. It could simply be that your squelch level is high and is just not unmuting due to that.
Along with that, I would also check your unmute rule, and set it to "Standard". And/Or, Or Unmute should not be selected. In the same screen IIRC should be the personality squelch level. All my astro's are set to 3, but your milage may vary. 7 is the common number that I have seen, and may be the default.
Short of all of that, the repeater should be checked 1st, as many are not properly aligned or maintained. PM on your side would be a good thing too. If your not able to, most Motorola shops usually charge an hour of labor to PM the radio.
Re: PL DECODE ON ASTRO SABER
Posted: Thu Mar 12, 2009 1:58 pm
by Astro Spectra
There are 'good' and 'bad' PL tones for the Astro Saber, Astro Spectra, and XTS 3000 depending on firmware.
Bad tones include 146.2 Hz, 151.4 Hz, 156.7 Hz, and 162.2 Hz when you are using a 12.5 kHz channel. Can't remember what firmware this problem relates to but I avoid these tones.
Since your tone is not one of these and I presume you’re using 25 kHz channels then as Pj suggests it could be deviation set up.
In 25 kHz systems with +/-5 kHz deviation the PL deviation should be 750 Hz and in 12.5 kHz systems with +/- 2.5 kHz the PL deviation should be about 500 Hz. Don’t forget to turn off the HPF in your radio test set or deviation meter when you make these measurements.
You may also want to check tone distortion on any modified kit as transmitters not designed to accept PL may badly attenuate the tone and depending where in the radio you inject the tone the PLL may actively attempt to cancel out the tone resulting in distortion of the tone waveform. That’s why many radios use so called two point modulation with the PL going to the reference oscillator. Lastly any encoder that doesn't use a crystal to generate PL tones is immediately suspect and should be replaced.