Maratrac Troubleshooting...

[Tony.RI]

Along with that MTVA I asked about in my other thread, I got two Maratrac radios, one VHF-High the other UHF. Anyways, the VHF model # is T73XTA7DA7BK and the UHF is T74XTA7DA2AK. Now, the radios came with only two A2 clamshell heads. Was it a bad idea to use the A2 clamshell on the A7 radio?
Secondly, the radio is receiving perfectly, but when I transmit, all it does is beep 2-times/second while the PTT is depressed. I've tried the hang-up box on both pins 24 and 30 to pin 27 with no change.

Thank's in advance!

[kf4sqb]

Was it a bad idea to use the A2 clamshell on the A7 radio?

Unlike the Spectra, the "A7" in the Maratrac model number doesn't denote which head it takes. Any Maratrac is compatible with any Maratrac head, with the exception of the A7 head that came with low-band radios, which has a squelch control on it. All you have to do to change heads is go into the RSS, and tell it which head you are going to use.

You can cheat a little with the clamshell heads. There are two different versions of the clamshell, one with two "zones" of eight channels each, for a total of 16, and one for eight channels with scan. Both heads are electrically identical, the only difference is the label on one of the switches. For the "zone" head, the switch is labeled "A" and "B", while it is labeled "On" and "Off" (IIRC) for scan. You can program the radio to use either one, no matter which one you actually have, and it will work properly.



For your other problem, are you sure the channels aren't programmed for RX only? Do you have the ignition control leads hooked to 12 VDC? Are your TX frequencies within the bandsplit of the radio?

[Tony.RI]

Was it a bad idea to use the A2 clamshell on the A7 radio?

Unlike the Spectra, the "A7" in the Maratrac model number doesn't denote which head it takes. Any Maratrac is compatible with any Maratrac head, with the exception of the A7 head that came with low-band radios, which has a squelch control on it. All you have to do to change heads is go into the RSS, and tell it which head you are going to use.

You can cheat a little with the clamshell heads. There are two different versions of the clamshell, one with two "zones" of eight channels each, for a total of 16, and one for eight channels with scan. Both heads are electrically identical, the only difference is the label on one of the switches. For the "zone" head, the switch is labeled "A" and "B", while it is labeled "On" and "Off" (IIRC) for scan. You can program the radio to use either one, no matter which one you actually have, and it will work properly.



For your other problem, are you sure the channels aren't programmed for RX only? Do you have the ignition control leads hooked to 12 VDC? Are your TX frequencies within the bandsplit of the radio?

Thanks for the quick reply!
The channels are programmed correctly, and they are within the radio's bandsplit (144-174.)
When I try to transmit, it sounds like beep-static-beep-static-beep-static... (if that makes any sense.) Could this be a problem with anything in the radio, (like capacitors or transistors?)

Also, what are the differences between the HCN1089A and HCN1052A control heads?

[wx4cbh]

Sounds as though you haven't changed the control head type in the RSS. It's under Service in the Main Menu.

[kf4sqb]

Also, what are the differences between the HCN1089A and HCN1052A control heads?

I don't know the exact difference, but they are both "A7" heads. At a guess, I would say they either re-designed part of the internal circuitry, or else changed from DIP construction to SMD construction. I'm pretty sure they changed the design of at least a voltage regulator circuit. That could be the difference, but I really don't know. Either will work the same.


As for your "beep problem", I'm not sure. As WX4CBH suggested, try checking to see what control head its programmed for. I've changed the type before myself, but I really don't remember what it does if the wrong head is selected, as it was at least seven years ago the last time I did it.

[Tony.RI]

Also, what are the differences between the HCN1089A and HCN1052A control heads?

I don't know the exact difference, but they are both "A7" heads. At a guess, I would say they either re-designed part of the internal circuitry, or else changed from DIP construction to SMD construction. I'm pretty sure they changed the design of at least a voltage regulator circuit. That could be the difference, but I really don't know. Either will work the same.


As for your "beep problem", I'm not sure. As WX4CBH suggested, try checking to see what control head its programmed for. I've changed the type before myself, but I really don't remember what it does if the wrong head is selected, as it was at least seven years ago the last time I did it.

The control head is programmed correctly, and the ignition switch is also setup. The mic hangup didn't change anything, either. I've checked the cable and it appears that there is nothing wrong with it, so that leaves only the radio or the head.

Here's a video I took today that I hope demonstrates the issue I'm having: http://www.youtube.com/watch?v=Yo45J8yNGd4&fmt=18

[Jim202]

My take on what I saw in the video clip is that what ever power source your running the radio from
does not have enough guts to supply the needed current in transmit.

Didn't pay any attention if you provided a model number or what power level the radio is. Here
is a hint, at the 100 watt TX power out level, you are looking at a current pull of about 22 to 28 amps
at the 13.6 volt level. If you have a 60 watt radio, then the current pull is some what reduced.

You can't run this radio off of a 10 amp bench supply. If your trying to run this off of a battery
with a charger, the battery is probably almost dead and the charger is only putting out a couple
of amps in a trickle mode.

Find a good solid source of DC power and then see if the transmitter plays a little better.

Jim

[Tony.RI]

My take on what I saw in the video clip is that what ever power source your running the radio from
does not have enough guts to supply the needed current in transmit.

Didn't pay any attention if you provided a model number or what power level the radio is. Here
is a hint, at the 100 watt TX power out level, you are looking at a current pull of about 22 to 28 amps
at the 13.6 volt level. If you have a 60 watt radio, then the current pull is some what reduced.

You can't run this radio off of a 10 amp bench supply. If your trying to run this off of a battery
with a charger, the battery is probably almost dead and the charger is only putting out a couple
of amps in a trickle mode.

Find a good solid source of DC power and then see if the transmitter plays a little better.

Jim

I'm really hoping its as simple as that! Its a 100W unit. I had it running off a 12AH SLA I had just charged that morning. I'm guessing I can try turning down the power level in RSS and run a few batteries in parallel.

[Tony.RI]

It looks like that was it! I turned down the power from the original setting of 83 to 25 and that seems to have fixed the issue.

Thank you very much for the help! This site never ceases to amaze me with how y'all help us noobs!

[Jim202]

You have now probably caused another problem. Many of the solid state PA units do not work very
well if the power is turned down beyond a certain point. Generally you can go 25% and stay out of
trouble. Beyond that it depends on the circuit design.

Normally the PA turns into a noise or comb generator in the low power setting. This causes all
sorts of noise and spurs to start showing up. Unless you have a spectrum analyzer, you probably
will never know the radio is doing the noise generation thing. Allowed to continue, you could
self destruct the PA in certain cases.

Bottom line, it is not a good idea to turn a solid state PA down much lower than about 25%.

In your case, you need to find a larger power supply system. Remember, a 100 watt radio eats
a bunch of 12 volts. Never seen a 100 watt radio use less than 22 amps at 13.6 volts. Have seen
a few go as high as 30 amps. Sort of depends on the frequency band, the efficiency of the circuit
design, how good of an antenna match and a few other meaningless factors.

Jim

It looks like that was it! I turned down the power from the original setting of 83 to 25 and that seems to have fixed the issue.

Thank you very much for the help! This site never ceases to amaze me with how y'all help us noobs!