Astro spectra as simplex remote base

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
User avatar
oh2lak
Posts: 237
Joined: Sun Nov 25, 2001 4:00 pm

Astro spectra as simplex remote base

Post by oh2lak »

Hi

I'm planning to use a 110W UHF Astro Spectra as a simplex remote base.

I have now gathered all necessary signals, audios in and out and COS from the audio PA, but PTT is missing. Is PTT available on either connectors? According to the service manual, there are pins marked as PTT but they do not work, do they have to be enabled prior operation?

..
Erik
--
Erik Finskas OH2LAK
[email protected]
User avatar
wavetar
Administrator
Posts: 7341
Joined: Sun Sep 09, 2001 4:00 pm

Post by wavetar »

PTT is available at the rear accessory cable on pin 13, however, the Astro Spectra by default comes configured for 'modem' connection, so pin 13 defaults to 'TX-RS232'. You need to move a surface mount jumper from one location to another on the command board. I don't have the information in front of me right now & won't until next week. If you have the detailed service manual, there's a jumper table in there which details what jumpers to move to accomplish different things. Maybe someone else with the manual in front of them can elaborate.

Todd
No trees were harmed in the posting of this message...however an extraordinarily large number of electrons were horribly inconvenienced.

Welcome to the /\/\achine.
User avatar
xmo
Moderator
Posts: 2549
Joined: Fri Oct 12, 2001 4:00 pm

Post by xmo »

JU518 - OUT
JU500 - IN
CTAMontrose
was grem467
Posts: 1145
Joined: Mon Jul 21, 2003 12:46 pm

Post by CTAMontrose »

Where are you tapping COR/COS from?
User avatar
wavetar
Administrator
Posts: 7341
Joined: Sun Sep 09, 2001 4:00 pm

Post by wavetar »

grem467 wrote:Where are you tapping COR/COS from?
Sounds like he's using the DC biasing voltage on the speaker outputs:
oh2lak wrote: audios in and out and COS from the audio PA
..
Erik
Todd
No trees were harmed in the posting of this message...however an extraordinarily large number of electrons were horribly inconvenienced.

Welcome to the /\/\achine.
User avatar
oh2lak
Posts: 237
Joined: Sun Nov 25, 2001 4:00 pm

Post by oh2lak »

Thanks for the info, I have to look at the boards when I next get a change to work on this project.

The COS signal is extracted from pin 10 of the audio PA, it was told to have a slight delay at the tail but I haven't noticed such. The pin goes up to Vcc when the audio PA needs to unmute, ie. when a signal is present in the RX or some beeps need to be emitted to the speaker. Good tip was to disable all beeps and tones, as they all pull that line up, and intention is to make the line go up only with a signal in the receiver.

I extracted also the PA on signal for a tx/rx relay, as the remote base will use a repeater antenna system, so I need to switch the antenna. A 9.6V signal is present at pin 15 of the feedthrough connector of the command board when TX is on, I used that.

Both the COS and PA on signals are buffered so there is no fear of overloading the original signal paths.

The radio boots up successfully without a control head, but I've investigated of using the emergency line to switch between two modes (to change TX power etc), but using a vRCH to control the radio would be the best. I'd hesitate to spend a RIB to the site just to control the radio, is the mini-rib schematic available somewhere? That would do the job controlling the radio, DSL is available at the site and there is already a W2k machine where the vRCH could run.

..
Erik
--
Erik Finskas OH2LAK
[email protected]
Post Reply

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