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Problem getting Astro Spectra to talk Astro

Posted: Thu Jun 26, 2003 1:23 pm
by astroiscool
I know I'm missing something here, I just know it.

Radio #1: Astro Spectra
Radio #2: Astro Saber III

Both radios on a repeater using network ID 123 work fine, both through the repeater and on direct/talkaround. (The repeater is a Quantar and is set to only TX/RX Astro Network ID 123.)

Put both radios on another Quantar repeater which uses Network ID 293 (both radios are programmed for Digital CSQ at this point) the Astro Saber will talk to the Spectra, either direct or through the repeater...but, the Astro Spectra will not talk to the Astro Saber.

What am I missing???

AIC

Posted: Thu Jun 26, 2003 1:32 pm
by The Pager Geek
Not secure right?

You have double checked the frequencies.

CF4M in options. If you have Select Call decodeon the Saber.. try removing that for a test. Or while Tx'ing from the spectra, monitor the output of the Quantar.. make sure it's coming out of the quantar.

If coming out of the quantar, try putting the Saber as DSQ, or hold the monitor button down while tx'ing with the spectra.

We'll start there....
tpg

Posted: Fri Jun 27, 2003 5:57 am
by astroiscool
Not secure -- in the clear.

Frequencies are correct.

CF4M is set in the ASTRO OPTIONS on both radios. (Astro Saber is known, working, and functions fine on both frequencies without fail or flaw)

Both quantars work fine... Allow me to reiterate the problem. Note: we are working with all astro radios here. saber = astro saber III, spectra = astro spectra

On network ID 123, I have no problems. I can talk, on direct, between both the saber and spectra. This is on a 464.xxxx frequency.

However, when I switch to a 442.xxxx frequency, and use DCSQ (network ID 293), I can talk from the saber to the spectra on direct, but when I TX on the spectra on direct, the saber acts like there's no signal there.

If I put the saber into MONITOR ON (I have a concentric switch configured accordingly) I will hear the digital sound as if the saber is not decoding the digital data properly.

Quantar is not really a factor here, other than the fact that we're dealing with two different repeater systems. One is on 464.xxxx with network id 123, the other is a ham repeater using digital CSQ, and TX using network ID 293.

When I use the astro spectra to TX on the 464.xxxx repeater, it works fine. However, when I switch to the ham repeater and TX, the ham repeater acts like it's not receiving anything. Again, all fingers pointing at the astro spectra as being the culprit.

Question: I should be able to use multiple network IDs across one radio, right?

Here's where it gets really weird:

I programmed a brand new channel into the spectra. I made it an ASTRO only channel (not mixed-mode) and used Digital CSQ. I used a simplex frequency for TX/RX. The same frequency was originally programmed in my saber the same way. Digital CSQ, TX network ID 293.

with this configuration, I can talk both ways, with the saber and spectra!

This is driving me nuttz!!!!!!! :evil:

Posted: Fri Jun 27, 2003 6:36 am
by xmo
Radio alignment is a prime suspect in cases like this.

The modulation balance adjustment is critical to proper digital modulation fidelity. This alignment is made at several frequency points accross the operating range of the radio. If the alignment is not done correctly the modulation fidelity could be worse at some frequencies than others. This could be compounded if the radio is a 450-512 range radio that has been forced out of band for the ham frequencies.

The bad thing is that if someone performed the modulation balance alignment without being aware of the potential problem - it is probably set wrong. The default settings for virtually every service monitor: R2670, R2001, HP8920, are wrong for this adjustment. Hundreds of radios have been sent back to the depot with nothing more wrong than this alignment foobared.

The latest versions of Motorola's maintenance manual for the Astro Digital Spectra Plus do give a new procedure for this alignment. They recommend the use of an HP modulation analyzer, but if you understand what they are doing with the filter settings - you can get by with a service monitor.

Posted: Fri Jun 27, 2003 8:42 am
by wavetar
XMO is correct, of course. There have been several other threads witrh the same issue...the UHF Astro radios will often not decode properly when forced into the ham band. Often you can align them to work, but they then may not work on other in-band frequencies.

Todd

Astro alignment

Posted: Fri Jun 27, 2003 9:35 am
by Microwave Mike
The HP Modulation Analyzer is the way to go when working on radios in the digital mode. The same analyzer is used to align service monitors.

mm

Posted: Sun Jul 06, 2003 5:48 pm
by RocketNJ
I've found you need to change some chip resistors to get the Astro deviation correct in the ham band. It is tricky to balance the mod comp both in-band and out of band.

George