No TX audio?

[jmfirefighter]

Hi folks-

My new VHF Astro Spectra (flashcode 500008-100A40-0, model T04KLH9PW9AN) with the W9 head that receives fine, and when the PTT on the mic is pressed it keys up and will open the carrier (can hear it opening on another radio.) However, it does not have any transmit audio.....any idea why this is happening? I get no error codes when the radio powers up.

If someone wants to take a look at my codeplug (the prior owner was using it on trunked systems, I am using it on conventional) and see if I am missing something, I will be more than willing to send it to you.

Give me some thoughts to look at folks.......I have taken the radio boards out, there is no capacitor leakage, no broken solder joints, and the VOCON appears to be in place and tight..

 

[jim202]

Hi folks-

My new VHF Astro Spectra (flashcode 500008-100A40-0, model T04KLH9PW9AN) with the W9 head that receives fine, and when the PTT on the mic is pressed it keys up and will open the carrier (can hear it opening on another radio.) However, it does not have any transmit audio.....any idea why this is happening? I get no error codes when the radio powers up.

If someone wants to take a look at my codeplug (the prior owner was using it on trunked systems, I am using it on conventional) and see if I am missing something, I will be more than willing to send it to you.

Give me some thoughts to look at folks.......I have taken the radio boards out, there is no capacitor leakage, no broken solder joints, and the VOCON appears to be in place and tight..

Try a different mic on it before you go too far.

 

[jmfirefighter]

That was my first thought too, I will do that today when I get to work as I can borrow a "known good" one from an ambulance to try it out.

 

[jmfirefighter]

No luck on the "known good" mic......any other thoughts?

 

[jmfirefighter]

I don't know if this might be affecting the voice transmit, but I do have the green and orange wires from the control head connected together running to my fuse block (not the car one, but an axillary block I installed for all my warning equipment/etc.) This is the same place the AS gets it's main power from, and I know /\/\ was specific about having that green wire run from the same source as the main lead.

Also, I have an in-line noise filter installed on the AS' main power lead, would that affect this?

I noticed that the radio shack adapter to go from UHF to mini-UHF seems to be loose, I am able to wiggle the antenna plug up and down/side to side when it is connected to the radio. It's as tight as I can get it. Would this allow the radio to receive OK, but not transmit well?

Listening to the radio today, all of the VHF P25 channels sound clear, voice sounds strong, and there is no interference. VHF analog comes across the same way. So I think with that can we rule out the vocoder since it decodes the P25? I would assume that with a faulty or poorly connected vocoder I would not receive either (correct me if I'm wrong).

When I transmit as a test on our local analog VHF private channel, I can hear the AS key up and open the squelch on my XTS2500. The open carrier doesn't sound "right", if that makes any sense. It is very scratchy, and quiet. Again, there is no audio, just the open carrier when speaking or blowing into the mic. The XTS2500, however, when keyed on the same frequency, has very a very crisp and clear carrier sound.

I'm at a loss as to why this radio is not working properly. Seller and I spoke, and he said it was working fine when it left his house (of course sellers can lie). I have a new connector for the antenna on order to see if that will change anything. I plan on checking continuity tonight on my control cable, pin for pin. I will also try moving the green wire directly to the same place the main lead is connected.

 

[scottbailey]

Listening to the radio today, all of the VHF P25 channels sound clear, voice sounds strong, and there is no interference. VHF analog comes across the same way. So I think with that can we rule out the vocoder since it decodes the P25? I would assume that with a faulty or poorly connected vocoder I would not receive either (correct me if I'm wrong).

Wrong - I'll put money on the vocoder. A vocoder can receive analog AND digital fine yet not pass any Tx audio on either analog OR digital - I've seen it myself and a vocon swap did the trick.

See this BatBoard thread:

Swap the vocon. All the audio (test or actual) is generated by the DSP on the vocon. If that's not it, the RF board is having fun with you....

When I transmit as a test on our local analog VHF private channel, I can hear the AS key up and open the squelch on my XTS2500. The open carrier doesn't sound "right", if that makes any sense. It is very scratchy, and quiet. Again, there is no audio, just the open carrier when speaking or blowing into the mic.

If it's not the mic, then it's probably the vocon. If you have another Astro Spectra radio to try, swap the vocon in and see if it fixes it. Just remember that you're going to want to align the radio after swapping another vocoder in as a permanent replacement.

Seller and I spoke, and he said it was working fine when it left his house (of course sellers can lie).

Maybe he's telling the truth - but maybe he only tested receive or not much transmit, if at all. If I'm not mistaken, that is a 110 watt radio - your average < 15amp power supply isn't going to have enough juice to transmit at all.

 

[jmfirefighter]

I have since sent the radio back to the seller for a refund, so he's going to take a look at it. I got tired of playing with it to figure out what was wrong.

Oh well. Thanks for all the help anyways.