Astro spectra P25 out of band

This forum is dedicated to discussions pertaining specifically to the Motorola ASTRO line of radios (those that use VSELP/IMBE/AMBE), including using digital modulation, digital programming, FlashPort upgrades, etc. If you have general questions please use the General or Programming forums.

Moderator: Queue Moderator

Post Reply
nb1h
New User
Posts: 13
Joined: Wed Oct 28, 2009 7:15 am
What radios do you own?: pretty much everything

Astro spectra P25 out of band

Post by nb1h »

Found this old thread on the same subject but I didn't want to post in a 3 year old thread:
http://batboard.batlabs.com/viewtopic.php?f=4&t=79962

I have two 110w K-split astro spectras with 11.71.07 (newest) firmware. They both transmit perfect p25 that I can decode with my uniden scanner. I have checked both radios with my service monitor and they are both tuned correctly.

Based on what I am reading in that other thread I linked, the new firmware version and proper tuning increase the chance that a particular radio will transmit p25 out of band.

I have a friend with a 453-486 split astro that does not transmit p25 in the ham band. I'm not sure what firmware he has.

Question is, would a firmware update possibly allow the 453-486 radio to transmit p25 in the ham band? I only have a couple flashes left so I don't want to waste one upgrading the radio unless it would help. I may also consider buying an S-split astro if I can be sure that it would transmit p25 at 442.3MHz. Has anyone with the newest firmware tried it, and how far down could you go?
jmr061
was KB9KST
Posts: 3176
Joined: Fri Sep 14, 2001 4:00 pm

Re: Astro spectra P25 out of band

Post by jmr061 »

No it will not without some s-record modifications and possibly hardware modifications.

Jason
motorola_otaku
Posts: 1854
Joined: Tue Jan 13, 2004 7:03 am

Re: Astro spectra P25 out of band

Post by motorola_otaku »

If I'm understanding you correctly, you have a friend's UHF Astro Spectra which operates in the UHF "3.5 range" of 453-488 MHz and you want to make it transmit P25 from 440 to 450 with a firmware upgrade. Ain't gonna happen. The only way to make UHF Astro Spectras transmit P25 out of band was with specially-modified codeplugs that had softpot alignment tuning points added in the 440-450 range. The hack was never publicly disclosed, although personally I suspect they were made with modern P25-capable versions of Astro Lab RSS.
jmr061
was KB9KST
Posts: 3176
Joined: Fri Sep 14, 2001 4:00 pm

Re: Astro spectra P25 out of band

Post by jmr061 »

I have heard that 438-470 records rammed in function fine in a range 3 radio (not sure about 3.5). I personally would do the hardware change too (range 2 parts).

Jason
nb1h
New User
Posts: 13
Joined: Wed Oct 28, 2009 7:15 am
What radios do you own?: pretty much everything

Re: Astro spectra P25 out of band

Post by nb1h »

Interesting. I wonder what the difference is between the VHF and UHF ones. I guess that 8mhz out of band for the UHF band is a lot different than 2 mhz out of band for VHF.
Post Reply

Return to “Legacy Batboard Motorola ASTRO (VSELP/IMBE/AMBE) Equipment Forum”