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GM300 UHF PL/CTCSS Question

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twillweaver
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GM300 UHF PL/CTCSS Question

Postby twillweaver » Wed Sep 12, 2018 4:55 pm

I have a GM300 8-ch UHF (438-470MHz) that I've reprogrammed for a few of the local repeaters near me. The main one I use is set up on channel 1 - I can receive and transmit with this one fine.

But with at least one of the rest of the programmed channels, I've noticed that the squelch doesn't open when the repeater transmits. Channel 3 for an example...

I have confirmed the Rx/Tx frequencies and the squelch tones with the listed repeater info, and I have the same programmed into both a Yeasu and Baofeng and they receive and play audio while the GM300 sits silently while the mic is hanging. Naturally, if I pick up the mic or press the monitor button, it plays received audio just fine.
I'm not sure what to do about this. Has anyone encountered this in the conversion of commercial-to-ham radio? I won't rule out that I'm just an idiot, but I'm really thinking that it's not me, this time.

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kb4mdz
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What radios do you own?: Too many for the time I have.

Re: GM300 UHF PL/CTCSS Question

Postby kb4mdz » Thu Sep 13, 2018 4:03 am

Poor PL decode? Poor PL Encode on the repeater output? (level too low, or distorted)?

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jackhackett
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Re: GM300 UHF PL/CTCSS Question

Postby jackhackett » Thu Sep 13, 2018 6:00 am

Is it a 12.5KHz radio? What is the model number?

If you have a 25KHz radio the PL level from a 12.5KHz repeater may not be high enough to open the squelch.

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jackhackett
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Re: GM300 UHF PL/CTCSS Question

Postby jackhackett » Thu Sep 13, 2018 7:20 am

Also, do you know what bandwidth the repeaters are using?

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Andy Corbin
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Re: GM300 UHF PL/CTCSS Question

Postby Andy Corbin » Thu Sep 13, 2018 7:21 am

Does the transmit tone on the GM300 open the repeater? Also, if you have an HT or another radio or even better yet, a service monitor, try setting the repeater output frequency and tone on one of them and see if it opens the receiver.

jpu535
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Re: GM300 UHF PL/CTCSS Question

Postby jpu535 » Fri Sep 14, 2018 9:37 am

I assume you are talking about ham radio use and not commercial part 90 2-way because then we would need more info on whether that radio has been modified for narrow band or not.

I believe this is going to be a programming issue. It's been a long time since I've been into a GM300 but check to see if you have a mute/unmute rule in your personality setting to make sure they are the same for the channel that does work. The fact that you are taking the mike off hook and you can hear in monitor mode is a classic sign that I have experienced in the past with bad programming with an unmute rule somewhere in the code plug. I believe you want standard/standard which means to unmute on proper PL and mute on loss of PL. I don't recall if the 8 channel radio is scan capable too but if you are trying to scan you could have an issue there if you are in scan mode. Like I said it's been a while for me with these GM300 so my information could be off a little too.

twillweaver
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Re: GM300 UHF PL/CTCSS Question

Postby twillweaver » Mon Oct 22, 2018 9:11 pm

Ok - first, I have to apologize for not getting back for so long. Life had plans I didn't anticipate. That said, I'd next like to thank everyone for their input. Awesome crew here.
To clarify, yes, I'm programming for Amateur Radio use. I used the published repeater information, and programmed my GM300. As I mentioned, the squelch didn't open when one of the programmed repeater transmitted. I finally just removed the RX tone requirement, and everything is good.

Once again, I thank all of you for your insight.

Jim202
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Re: GM300 UHF PL/CTCSS Question

Postby Jim202 » Thu Oct 25, 2018 3:04 am

Another fine database missing important information. Not unusual to run into this from the different databases available on the Internet.

With that said, I would get on the repeater in question and try to find someone that has some good information on the repeater. Ask them if the repeater does in fact transmit a PL tone. If the repeater does transmit a PL tone, ask what it is. It may not be the same as what is required on the input of the repeater. Most of them don't transmit a PL tone on the output. But you may get lucky and find one that is sending out the PL tone on the output frequency.

Trying to rely on getting enough of a PL tone to open up a receiver that is looking for it can be a real challenge. Most repeaters have built in filtering that will strip off the input signal's PL tone and not allow it to pass through the repeater audio path. This may be why you can't get your receiver to open up when you had it programed for PL receive.


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