Batboard

Hi Folks-

I have a recently acquired /\/\ Astro Spectra high-power VHF (flashcode 500008-100A40-0, model T04KLH9PW9AN) with a W9 head that has an interesting issue. I purchased it from a member here who said that it worked fine (and I believe him) but after installing and programming my frequencies it appears to not be transmitting audio. When I key up my receive radio reads the open carrier and it is very noisy (scratchy). If you listen really close (ie receive radio turned all the way up with your ear to the speaker) you can hear very faint audio, but for practical purposes it might as well not even be there. The previous owner was using it primarily for trunked systems (at least from the codeplug that was in it) and I am using it for conventional VHF.

I've tried a different mic, which is known to be good, with no change. I've tried a different antenna with no change. I tried a different control cable with no change. I even changed out my radio for one in our trucks (control head and drawer unit) to make sure it wasn't my wiring that was messed up with no change. Like I said, it receives great, both analog and digital communications are loud and clear. It decodes and displays ID numbers fine with digital communications. All the buttons on the control head work. It is definitely drawing power when it's keyed up as the lights dim in the car with it not running. I took the radio apart and looked for cap leakage, there was none found. I've since disassembled the radio twice to make sure everything is seated properly and there are no broken wires, bent pins, or unhooked cables (there are none). No bent pins on the control cable or back of the control head. The radio was NOT transmitted with no load attached to it while it was in my possession (I took great care to NOT do that).

I had a line filter installed initially, thinking that may be causing some sort of issue I uninstalled it with no change. It is not directly hooked to the battery, but it is run off of an "auxiliary" fuse panel that I installed for all my lights/etc. which is direct fed from the battery with a 200 amp rated control solenoid which is connected to a switched power source. I don't believe this is an issue though because it does not work in another vehicle with known good wiring.

Anyone have any ideas what might be causing this radio to behave this way? I am planning on taking it to a radio guy to have it looked at, but is there anything I can look at in the mean time? Could I have missed some little setting or check box in the codeplug that would cause this issue? The prior owner suggested programming a MDC burst into the radio to see if it transmits that, but I'm not too familiar with MDC settings (we really don't use it around here) so I probably didn't set it up right.

If someone wants to take a look at my codeplug to make sure I didn't screw something up, I'll be more than happy to send it to you.

Hopefully this is just something stupid or is easy to fix so I can get this radio up and running. Man this is frustrating!

Thanks for any help you can offer.

Josh

jmfirefighter20 wrote:Hi Folks-

I have a recently acquired /\/\ Astro Spectra high-power VHF (flashcode 500008-100A40-0, model T04KLH9PW9AN) with a W9 head that has an interesting issue. I purchased it from a member here who said that it worked fine (and I believe him) but after installing and programming my frequencies it appears to not be transmitting audio. When I key up my receive radio reads the open carrier and it is very noisy (scratchy). If you listen really close (ie receive radio turned all the way up with your ear to the speaker) you can hear very faint audio, but for practical purposes it might as well not even be there. The previous owner was using it primarily for trunked systems (at least from the codeplug that was in it) and I am using it for conventional VHF.

I've tried a different mic, which is known to be good, with no change. I've tried a different antenna with no change. I tried a different control cable with no change. I even changed out my radio for one in our trucks (control head and drawer unit) to make sure it wasn't my wiring that was messed up with no change. Like I said, it receives great, both analog and digital communications are loud and clear. It decodes and displays ID numbers fine with digital communications. All the buttons on the control head work. It is definitely drawing power when it's keyed up as the lights dim in the car with it not running. I took the radio apart and looked for cap leakage, there was none found. I've since disassembled the radio twice to make sure everything is seated properly and there are no broken wires, bent pins, or unhooked cables (there are none). No bent pins on the control cable or back of the control head. The radio was NOT transmitted with no load attached to it while it was in my possession (I took great care to NOT do that).

I had a line filter installed initially, thinking that may be causing some sort of issue I uninstalled it with no change. It is not directly hooked to the battery, but it is run off of an "auxiliary" fuse panel that I installed for all my lights/etc. which is direct fed from the battery with a 200 amp rated control solenoid which is connected to a switched power source. I don't believe this is an issue though because it does not work in another vehicle with known good wiring.

Anyone have any ideas what might be causing this radio to behave this way? I am planning on taking it to a radio guy to have it looked at, but is there anything I can look at in the mean time? Could I have missed some little setting or check box in the codeplug that would cause this issue? The prior owner suggested programming a MDC burst into the radio to see if it transmits that, but I'm not too familiar with MDC settings (we really don't use it around here) so I probably didn't set it up right.

If someone wants to take a look at my codeplug to make sure I didn't screw something up, I'll be more than happy to send it to you.

Hopefully this is just something stupid or is easy to fix so I can get this radio up and running. Man this is frustrating!

Thanks for any help you can offer.

Josh

The problem with trying to swap both the radio and head is that they are programmed for each other. Unless you take just the head and swap it with the original, your not able to point the finger at just one item being bad. The same with the radio. Unless both radios are programmed the same, the head needs to stay with the radio. I am leaning on the radios are a trunk mount, but I am not sure.

In your description of the steps you said you took in the swap, I am a little lost. Did I read it correctly that you did move both the radio and head from the fire truck and put it in your vehicle to try. It didn't have any TX audio.

Before we go much further, please clear up the issue if the radios are a dash mount (control head mounted on the radio) or if these are a trunk mount with the control head only at the dash.

If the radios are in fact a trunk mount with a control cable and you swapped both the radio and control head at the same time, your looking at a damaged control cable in your vehicle. If this is the case and you have a trunk mount, I suspect you will find a cut or pinch in the remote control cable someplace. It has lost the mic low line or the mic high line is shorted to ground.

Jim

Both the radio and the head (mine) were moved from my vehicle to the ambulance. I used the ambulance's known good wiring/antenna/control cable setup to see if it was my cable, wiring, or my radio with the issue. It had the same issue of low/no tx audio when swapped into the ambulance.

are you using a dtmf mic by chance?

Nope. Standard mic.

Use a different control head. The W9 hads gets its programming from the radio so no issue with swapping heads. Use this to determine if it is the control head or the drawer unit. Did you get this all as package deal or did you just pick up the drawer and add parts?

Jason