Monitoring APCO-25 IMBE Without Affiliating: Can It Be Done?

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Johnny Galaga
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Monitoring APCO-25 IMBE Without Affiliating: Can It Be Done?

Post by Johnny Galaga »

Is there any way to program an Astro Saber or an XTS3000 model III to receive digital APCO-25 audio on a 3600 baud control channel without affiliating ? It would be nice if you didn't have to set it as SmartZone.
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Johnny Galaga
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Post by Johnny Galaga »

So do I simply set the Tx Voice/Signal Type to DIGITAL, or are there any other parameters I need to change ?
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Johnny Galaga
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Post by Johnny Galaga »

Looks like I answered my own question because I just got it working. I'm now listening to digital talk groups for the first time ever. YES !! :P
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Josh
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Post by Josh »

Johnny Galaga wrote:Looks like I answered my own question because I just got it working. I'm now listening to digital talk groups for the first time ever. YES !! :P
Ahh what a feeling it is. I felt the same way.

At any rate, if your system is only one site or is a group of simulcast sites using no more than 4 control channels, if your radio supports it, program the system as Smartnet and the affiliation as "on-PTT" then program a button or a switch as TX inhibit and the radio won't transmit.

-Josh
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Johnny Galaga
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Post by Johnny Galaga »

Ahh what a feeling it is. I felt the same way.
That's right ! No more secrecy. It's kinda wierd how it sounds so similar to a cell phone.

At any rate, if your system is only one site or is a group of simulcast sites using no more than 4 control channels, if your radio supports it, program the system as Smartnet and the affiliation as "on-PTT" then program a button or a switch as TX inhibit and the radio won't transmit.

-Josh
That's exactly what I did, but unfortunately the system is SmartZone. It's still awesome to finally be able to listen to it for the first time ever. I set both positions of the concentric switch to Tx Inhibit so the radio cannot possibly transmit. The only way to make the radio transmit is to reprogram it which is exactly what I want. That way if it gets lost or stolen, the theif won't be able to maliciously interfere with the radio system.
SmackDaddy
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Post by SmackDaddy »

Ok, here is another question that is related to the original topic of "Monitoring Responsibly".

With a VHF or UHF radio, you obviously have to set the Base/Offset information in order for trunking to work. I know there is a spot to set RX and TX ranges.

Now, what happens if you properly set the RX ranges, but purposely set the TX ranges to something invalid (ie. Ham band frequencies, whatever) ? Will this guarantee that your VHF/UHF radio will never TX directly on the system itself? I'm assuming so.

Combine this offset trick with the TX inhibit, and I bet you are almost guaranteed to be safe. Of course this offset trick won't work on 800 MHz.

Anyone ever looked at this?

Thanks,
SD.
tj173
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Post by tj173 »

I tried that here on the trunked sysytem I listen to. The radio wouldn't scan all of my scan list. It seemed like the radio was stuck on one control channel and I only heard audio when traffic came across that channel. I wound up having to keep the tx and rx channels set as they would be on any other radio in the system.

T.J.
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Twisted_Pear
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Post by Twisted_Pear »

SmackDaddy wrote:Ok, here is another question that is related to the original topic of "Monitoring Responsibly".

With a VHF or UHF radio, you obviously have to set the Base/Offset information in order for trunking to work. I know there is a spot to set RX and TX ranges.

Now, what happens if you properly set the RX ranges, but purposely set the TX ranges to something invalid (ie. Ham band frequencies, whatever) ? Will this guarantee that your VHF/UHF radio will never TX directly on the system itself? I'm assuming so.

Combine this offset trick with the TX inhibit, and I bet you are almost guaranteed to be safe. Of course this offset trick won't work on 800 MHz.

Anyone ever looked at this?

Thanks,
SD.
Yeah, I have done it and you have a surefire way of not transmitting on the network. Just be careful you don't pick the correct Tx values by accident! I usually try and figure them out for the heck of it.

-Wayne
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Barry Dehatchit
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OTB without affiliation

Post by Barry Dehatchit »

I've found that setting up a bogus input range without disabling tx causes problems. The radio either tries to affiliate and goes out of range when unable or it moves to the next site and tries to affiliate. Either way youre sol as far as monitoring goes. Battery life is also decreased as your radio is continously trying to affiliate.

However, the bogus input range combined with tx disable is the way to go. Radio never tries to affiliate and if it does, you are safe.
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ExKa|iBuR
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Post by ExKa|iBuR »

Sorry to re-hash an old thread here, but...

I highly doubt this would be possible, buuuuut..

Is there some way to program a VHF astro (XTS 3000) for Smartzone, with the wrong TX frequencies (ie...in a ham band or something), and have it try to affiliate...but have it not care if it affiliates or not - ie, it'll still receive?

This would make life easier not having to worry about annoyances like which talkgroup is on which tower.

-M
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N4KVE
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NO AFFILIATION

Post by N4KVE »

I just use the wrong connect tone. RX is perfect but if you hit TX by mistake you don't key up the system. :lol: I do this on smartnet. Smartzone is coming soon. Will this be ok? 73's to all. GARY N4KVE
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batdude
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uh...

Post by batdude »

the CT trick doesn't work... all it will do is prevent the audio from passing to the system.... you can still key it up



doug
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Re: NO AFFILIATION

Post by wavetar »

N4KVE wrote:I just use the wrong connect tone. RX is perfect but if you hit TX by mistake you don't key up the system. :lol: I do this on smartnet. Smartzone is coming soon. Will this be ok? 73's to all. GARY N4KVE
You don't understand what the connect tone is for. It is ONLY used to let the controller know the conversation is still going on, NOT to initiate the conversation. The channel grant is requested & given completely on the control channel, no connect tone involved. A unit programmed with the wrong connect tone will still get the channel grant, and the assigned repeater will key-up for the programmed amount of hang-time while it looks for the connect tone. If it doesn't see the proper connect tone, it will then drop the repeater.

Todd
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Post by wavetar »

Twisted_Pear wrote:
SmackDaddy wrote:Ok, here is another question that is related to the original topic of "Monitoring Responsibly".

With a VHF or UHF radio, you obviously have to set the Base/Offset information in order for trunking to work. I know there is a spot to set RX and TX ranges.

Now, what happens if you properly set the RX ranges, but purposely set the TX ranges to something invalid (ie. Ham band frequencies, whatever) ? Will this guarantee that your VHF/UHF radio will never TX directly on the system itself? I'm assuming so.

Combine this offset trick with the TX inhibit, and I bet you are almost guaranteed to be safe. Of course this offset trick won't work on 800 MHz.

Anyone ever looked at this?

Thanks,
SD.
Yeah, I have done it and you have a surefire way of not transmitting on the network. Just be careful you don't pick the correct Tx values by accident! I usually try and figure them out for the heck of it.

-Wayne

I accidentally did this once (wrong tx range) while setting up a 4 channel UHF trunked system. The radios would not pick-up the control channel at all, even though the receive range was correct. I went so far as to scope the discriminator & could see when the radio would cycle to the control channel as it went through it's programmed list, but would only remain on it for a few seconds & then continued scanning. I finally figured out what the heck I did wrong, but never could figure out why it wouldn't pick up the control channels properly. Radios were MTX8000 B4 models, without using any type of affiliation or coverage types.

Todd
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Post by ExKa|iBuR »

What Todd said, and Connect Tones don't mean anything on SmartZone systems. Sure, you can program it to whatever you want, but the site controller spits out the correct connect tone for that site. For example, here in Ontario, we have a 32 site VHF Smartzone system, I've come across, so far, 4 different connect tones on the towers closest to me.

-Mike
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Post by wavetar »

ExKa|iBuR wrote:What Todd said, and Connect Tones don't mean anything on SmartZone systems. Sure, you can program it to whatever you want, but the site controller spits out the correct connect tone for that site. For example, here in Ontario, we have a 32 site VHF Smartzone system, I've come across, so far, 4 different connect tones on the towers closest to me.

-Mike
I'm not quite following you. The connect tone is generated by the field radios, not the system. The tone is picked off of the repeaters receiver & routed to the controller to indicate conversation is still going on. The field radios are only capable of generating a single connect tone, so I'm not sure what you're seeing.

Todd
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Post by ExKa|iBuR »

No no, what I mean is this:

On a Privacy Plus system or whatever (non SmartZone), let's say the connect tone is 105.8 (or whatever they are)...

The site controller is looking for this connect tone.

In a SmartZone system, the site controller transmits the connect tone value, not the actual connect tone - much the same way it broadcasts it's system ID. The subscriber radio sees what the correct connect tone is, and transmits that. I didn't mean to imply the trunking repeaters transmit the connect *tone*, rather the connect tone *value*

Sorry, it's early :)

-Mike
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Post by ExKa|iBuR »

Kinda related to this;

In the RSS for 800MHz trunking, you can select Trunking Offset to be either the standard 45MHz, or not so standard 39MHz.

I was thinking that if you set it to 39MHz, your radio might still try and TX, but it won't actually be heard by the system. However, when you program it with this offset, the radio refuses to receive anything. Anyone got any clue why?

-Mike
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Post by ExKa|iBuR »

wavetar wrote:[adios were MTX8000 B4 models, without using any type of affiliation or coverage types.
Todd
I presume you meant MTX2000, as the MTX8000 doesn't do UHF. Well, technically 800MHz is UHF I guess, but you know what I mean.

-M
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Post by wavetar »

I'll have to take your word on it, as I wasn't aware of that for SmartZone systems. I would've thought the radio wouldn't have a 'connect tone' field in them for SmartZone if that were the case. Now I'm curious...I'm going to try that with a couple of radios on our system very soon...

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Post by ExKa|iBuR »

Well, that's what I've been told by a few Motorola types, as well as people who know quite abit about smartzone, but who knows.

It would make sense, as if you run something like Trunker or Treport, you'll see it gets the connect tone for you...and here in Ontario, as I was saying before, on 4 different sites, I've seen 4 different connect tones for each.

Considering the subscriber radios only have one trunking system in them, the only way they can get the correct connect tone is if the system tells them what it is.

Try programming a smartzone radio with a connect tone you know to be wrong for the tower it's on, and see what happens - I guess that's the best test.

-Mike
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Post by wavetar »

ExKa|iBuR wrote:
wavetar wrote:[adios were MTX8000 B4 models, without using any type of affiliation or coverage types.
Todd
I presume you meant MTX2000, as the MTX8000 doesn't do UHF. Well, technically 800MHz is UHF I guess, but you know what I mean.

-M
Well, they were actually MTX838, but I generally refer to them on the board as MTX8000 for our friends in the U.S.

Todd
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Post by Twisted_Pear »

wavetar wrote:
I accidentally did this once (wrong tx range) while setting up a 4 channel UHF trunked system. The radios would not pick-up the control channel at all, even though the receive range was correct. I went so far as to scope the discriminator & could see when the radio would cycle to the control channel as it went through it's programmed list, but would only remain on it for a few seconds & then continued scanning. I finally figured out what the heck I did wrong, but never could figure out why it wouldn't pick up the control channels properly. Radios were MTX8000 B4 models, without using any type of affiliation or coverage types.

Todd
The whole can't receive an ack OSW go OOR must have been started at a certain firmware version. Both the XTS I have will work on SmartZone networks even when they can't properly communicate with the controller. I know for sure my 800 does it. I'm pretty sure my UHF one does too.

Here are the specs:
800: R04.01.02 / DSP 06.03.01
UHF: R07.00.01 / DSP 07.03.06

Btw, SmartZone networks send out a global and site specific connect tone in the background status words. I believe part of the SZ firmware is to take these values versus programming. Or maybe the programming has to match the global tone, which permits taking the CT off-air. Dunno, never experimented.

-Wayne
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