APX Trouble with talk-around on APX 6000Li?

[KD9IXD]

I'm working with an agency (M) that has TA enabled on their radios via the concentric switch at the top. They are telling me that the radios can receive but not transmit while on TA.

The first time this happened I suspect it was a bad radio. Testing the radio found a much higher TX power than it's programmed for. An audio test (tuning to the problem channel with TA enabled) resulted in a lot of static. I could barely hear my coworker. Changing the mics didn't help and the radio is going in for repair. (The radios are programmed for 5W and this was outputting 7.5+. Normally we don't consider an extra 1.5 or so to be an issue, but I thought maybe the radio got damaged with the extra power)

Recently this happened again while they were coordinating with another agency, S. M was using the TA function on S's repeated channel. When they'd go off TA they couldn't transmit because of an incorrectly programmed TX frequency. This has since been fixed. But the RX is correct as is S's PL tones in M's radios. M could hear S, but not the other way around.

Other stuff:
-Both agencies are VHF. These frequencies are 150-160MHz.
-Both agencies have their own repeater. M are experienced users and I'm confident they are using their radios correctly.
-M's radios are very new, ~8 months.
-M's repeater uses a DPL and S's uses a PL. These are programmed correctly.
-I connected another of M's radios to a modscope. As far as I can tell, the radios are entering TA correctly (changing between Tx and TA frequencies).
-My boss said that TA changes the PL/DPL tones but the modscope didn't show any changes. Unsure if Motorola's documentation supports this.
-I've read that DMR radios on TA can interfere with radios using the repeater, but this issue is radio-to-radio, not radio-to-repeater so I don't know if this applies or not.
-I know that TA is usually enabled by a channel programmed with Rx=Tx and I've read that numerous times while researching this. We do that for our city. In this situation I did not, I think because I wasn't aware of this issue.
-TA range is about a mile, depending. If M and S were on a scene I don't think they'd be over a mile apart.

Does anyone have any insights? Clearly it isn't working, but that doesn't tell me WHY it's not working. Even if M had the wrong Tx frequency for S's repeater, the TA should still work because it operates on the output frequency of the repeater.

 

[Tech21]

In simplex mode, the tx and rx frequency should be the same. Add a test simplex channel in two radios using the frequency your agency uses.
Under conventional personalities, add the simplex channel. The rx and tx should be the same., leave the direct/ta box unchecked. Add your TPL/DPL codes and leave everything else default. Then, go to Zone Channel Assignment add a zone with just the test simplex channel. Name the channel, choose conventional and then the personality.

Do this to test the operation yourself and make sure the channel works first.

 

[mmckenna]

I have always been reluctant to use the Talk Around feature on the radios. Just gets too confusing for some users.
Since most modern radios have lots of memory capacity, I programmed a separate channel as simplex. I made sure it was very clear on the display that it was a different channel than the standard repeater setup.

 

[Thunderknight]

I have always been reluctant to use the Talk Around feature on the radios. Just gets too confusing for some users.
Since most modern radios have lots of memory capacity, I programmed a separate channel as simplex. I made sure it was very clear on the display that it was a different channel than the standard repeater setup.

Same. I always add the "D" version of the National Interop channels too...I wouldn't even consider the talk-around selection option.

 

[KD9IXD]

In simplex mode, the tx and rx frequency should be the same. Add a test simplex channel in two radios using the frequency your agency uses.
Under conventional personalities, add the simplex channel. The rx and tx should be the same., leave the direct/ta box unchecked. Add your TPL/DPL codes and leave everything else default. Then, go to Zone Channel Assignment add a zone with just the test simplex channel. Name the channel, choose conventional and then the personality.

Do this to test the operation yourself and make sure the channel works first.

I know the frequencies should be the same.
I've tested the channel out using the TA toggle so I know the channel works. I've verified the frequencies with 2 people involved. My coworker suggested the flash codes could be different and maybe that's a problem?
I don't see what the difference would be between adding a simplex channel and using the TA feature. They are the same function.

 

[KD9IXD]

Same. I always add the "D" version of the National Interop channels too...I wouldn't even consider the talk-around selection option.

We add the Direct ones too. I assumed that was required?

 

[KD9IXD]

I have always been reluctant to use the Talk Around feature on the radios. Just gets too confusing for some users.
Since most modern radios have lots of memory capacity, I programmed a separate channel as simplex. I made sure it was very clear on the display that it was a different channel than the standard repeater setup.

This is what we usually do. I didn't when I first made the codeplug because I didn't know this would be an issue. We use the simplex channel for our agencies and others too...just no one told me. And no one has a good reason why.

 

[mmckenna]

I know the frequencies should be the same.
I've tested the channel out using the TA toggle so I know the channel works. I've verified the frequencies with 2 people involved. My coworker suggested the flash codes could be different and maybe that's a problem?
I don't see what the difference would be between adding a simplex channel and using the TA feature. They are the same function.

Flash code shouldn't impact talk around at all.

 

[Thunderknight]

We add the Direct ones too. I assumed that was required?

The NIFOG says you can use the TA if the users have the option available and know how to use it. Hence it’s easier to just put in the “D” version

 

[KD9IXD]

Thanks!

 

[KD9IXD]

Flash code shouldn't impact talk around at all.

I hoped it wouldn't. Thanks.

 

[chief21]

-My boss said that TA changes the PL/DPL tones but the modscope didn't show any changes. Unsure if Motorola's documentation supports this.

In my experience, there is no change. TA uses the same TPL/DPL as the related repeater channel.

 

[TampaTyron]

You are right, it should be the same. However, in the interest of identifying a firmware bug or a codeplug programming defect, I would program the TA function AND a separate simplex channel that has the correct freqs and PL codes in it (or 2 simplex channels, one for M and one for S). See if operation/behavior on the simplex matches the TA function on M and S radios. If the simplex and TA behavior/operation in not the same, then you will need to investigate. Maybe firmware issue, maybe codeplug programming issue. TT

 

[TampaTyron]

In my experience, there is no change. TA uses the same TPL/DPL as the related repeater channel.

The only caveat to that is some channels have different tx vs rx PL/DPL codes due to interference or to try to keep Baofeng users off the repeater. Some radios do not handle this split PL/DLP issue well when going into the TA mode. This is why the simpmex channel isolates these dependencies. TT

 

[KD9IXD]

In my experience, there is no change. TA uses the same TPL/DPL as the related repeater channel.

I connected a radio up to a modscope and didn't find a difference so I agree.

 

[KD9IXD]

You are right, it should be the same. However, in the interest of identifying a firmware bug or a codeplug programming defect, I would program the TA function AND a separate simplex channel that has the correct freqs and PL codes in it (or 2 simplex channels, one for M and one for S). See if operation/behavior on the simplex matches the TA function on M and S radios. If the simplex and TA behavior/operation in not the same, then you will need to investigate. Maybe firmware issue, maybe codeplug programming issue. TT

Thanks!
Aside from the obvious-communications working (or not) with the simplex va TA-is there something else I could look for that would indicate a problem?

 

[KD9IXD]

The only caveat to that is some channels have different tx vs rx PL/DPL codes due to interference or to try to keep Baofeng users off the repeater. Some radios do not handle this split PL/DLP issue well when going into the TA mode. This is why the simpmex channel isolates these dependencies. TT

That's really interesting. I'm not very familiar with Baofengs, other than they're cheap and poorly made. I'm curious about your comment of keeping baofeng users off the repeater.

Luckily these agencies aren't using split PL/DPL tones. That would add another level of complexity to this!

 

[N4KVE]

That's really interesting. I'm not very familiar with Baofengs, other than they're cheap and poorly made. I'm curious about your comment of keeping baofeng users off the repeater.

Because sometimes their operating habits are as poor as the quality of their radios. Also, if you’ve been watching TV, many of the looters, & anarchists, seem to carry Baofengs. They don’t carry APX’s, XTS’s, etc. They seem to be a favorite of the pepper crowd. Where I live, repeater owners use RAS, or split PL/TPL tones to keep Baofengs, Wouxons, TYT’s & other similar radios off their repeaters.

 

[TampaTyron]

If not working split tone, then you should be able to work talk around no problem. There is one other issue that may be affecting you, depending on band, power, and distance from repeater..... Users may be desensing each other if they are in close proximity, operating far from the repeater, etc. You can verify this by seeing if you can degrade the other agencies audio on their frequency by transmitting on your frequency when they are receiving a transmission on their frequency. Other than that, it is possible that radios and repeaters are out of alignment, but usually not enough that it prevents basic analog simplex. TT

 

[KD9IXD]

You can verify this by seeing if you can degrade the other agencies audio on their frequency by transmitting on your frequency when they are receiving a transmission on their frequency.

This is what I was sent:
"M would receive transmissions but wouldn’t transmit on S's channel...The chief, using Radio # 1, switched several times from scanning to not scanning to talk around to repeater and nothing made a difference."

I just confirmed that M and S were trying to use S's repeater. I found a tx frequency error in M's radio for that repeater so them not being able to transmit makes sense. However, that they were unable to tx on TA doesn't make sense. Unless they were and no one was hearing them due to desensing?
BUT: The repeater is conventional and both agencies radios were tuned into it, so wouldn't 2 radios would have to be transmitting at the same time? One on the repeater and on one TA? Or I guess both on TA if they're physically close enough though I did test this by putting 2 of M's radios right next to each other and PTT-ing on the same channel with/without TA. I didn't see anything immediate.

Unless someone not involved in this response was also using S's repeater and the timing just happened to coincide? Possible, but unlikely. The response was occuring about 1 mile from S's repeater.

If it were somehow a timing issue, is there a way to check?