Communications Support Forums
Hi there,
A few months ago I have purchased an Astro Spectra Plus unit from E-bay. The radio was sold as parts or not working.
Radio's specs:
Model: T04KLH9SW3AN
Flashcode: 580008-000480-2
HOST: R08.01.03
DSP: R08.01.03
Vocon: 4 MEG
CPS used: R20.00.00
The radio was sold as parts without any accessories, but when I opened up the radio it seemed untouched and nothing was missing. Even the Vocon was in place! I have checked all modules, panels, connectors but everything was just fine so I gave it a try and powered it up connected to a dummy load.
Guess what?
It was working fine. Powered up immediately, passed self check and it was fine both in Rx and in Tx. I hooked it up to my PC and read it with the CPS. Codeplug can be read and write without any issues. My CPS (PatMob.exe) was previously modified to accept frequencies below 146 MHz (to accept VHF frequencies from 136-174 MHz). I have entered some frequencies below its official lower bandsplit limit, freqs for local simplex channels, like 144 and 145 MHz values. Accidentally I have set the Tx Mode to ASTRO (what I have not noticed at that moment). Since everything was fine, I have attached the radio to my main VHF antenna and pushed the PTT button to see what happens. In next few seconds I almost had a heart attack....one of my friends answered back: "Hey Tom, is that you in P25? I read you loud and clear"....
What the.....FFFF....???? How is that possible? The radio was not modified physically, the codeplug was not hacked....how is this possible? How can it work below 146 MHz with normal digital deviation levels? The other ham station is 30 miles away from me...
How is this possible? Maybe some of you can answer this. I have no idea. This shouldn't work but it IS working. But how? I always thought that there is a straight deviation limit below and above each band limits, the radio's firmware itself cuts the deviation below 1 kHz (2.75-2.85 kHz is needed to have a proper level used by P25). The limit was always a P.I.T.A. when I was working with older VSELP and IMBE gear.
Thanks in advance.
A few months ago I have purchased an Astro Spectra Plus unit from E-bay. The radio was sold as parts or not working.
Radio's specs:
Model: T04KLH9SW3AN
Flashcode: 580008-000480-2
HOST: R08.01.03
DSP: R08.01.03
Vocon: 4 MEG
CPS used: R20.00.00
The radio was sold as parts without any accessories, but when I opened up the radio it seemed untouched and nothing was missing. Even the Vocon was in place! I have checked all modules, panels, connectors but everything was just fine so I gave it a try and powered it up connected to a dummy load.
Guess what?
It was working fine. Powered up immediately, passed self check and it was fine both in Rx and in Tx. I hooked it up to my PC and read it with the CPS. Codeplug can be read and write without any issues. My CPS (PatMob.exe) was previously modified to accept frequencies below 146 MHz (to accept VHF frequencies from 136-174 MHz). I have entered some frequencies below its official lower bandsplit limit, freqs for local simplex channels, like 144 and 145 MHz values. Accidentally I have set the Tx Mode to ASTRO (what I have not noticed at that moment). Since everything was fine, I have attached the radio to my main VHF antenna and pushed the PTT button to see what happens. In next few seconds I almost had a heart attack....one of my friends answered back: "Hey Tom, is that you in P25? I read you loud and clear"....
What the.....FFFF....???? How is that possible? The radio was not modified physically, the codeplug was not hacked....how is this possible? How can it work below 146 MHz with normal digital deviation levels? The other ham station is 30 miles away from me...
How is this possible? Maybe some of you can answer this. I have no idea. This shouldn't work but it IS working. But how? I always thought that there is a straight deviation limit below and above each band limits, the radio's firmware itself cuts the deviation below 1 kHz (2.75-2.85 kHz is needed to have a proper level used by P25). The limit was always a P.I.T.A. when I was working with older VSELP and IMBE gear.
Thanks in advance.