I am trying to set up an ASL3 node via RF to my repeater. There is no internet at the repeater site. I am using ASL3, Repeaterbuilder RIM-MAXTRAC URI with a Motorola CDM750.
The ASL3 node works as it should with a simplex frequency. When I change to the repeater channel I get this weird “ping pong” deal. I have tried every possible combination of configuration in simpleusb and usbradio. I tried a different radio and another ASL3, HamVoip nodes, same issue. I have tried all the different duplex settings and TX/Rx delays. I have spent several hours with Scott from Repeaterbuilder and we are stuck. It works great with the simplex channel in the radio, but not the repeater channel.
I am missing something but just cannot figure it out. Has anyone else encountered this issue and how did you resolve it?
First, Scott is a smart guy. What did he think is happening?
I think rpt.conf settings duplex = 0 and linktolink = no should prevent that. Be sure the node is not sending any courtesy tones. Also check that the CDM programed as a normal repeater user.
Is there a hang timer on your repeater? Can it be turned off or the PL disabled during hang time and IDing? Is the CDM set for PL decode?
Is your node connected to anything other node during testing?
It's also not clear from your description what your actual hardware topology is or how you're actually trying to connect everything. You have a CDM750 presumably connected to the RIM-MAXTRAC. That's plugged into some sort of ASL3 system. But what's after that? Are you using a second adapter to the repeater on a different node number and linking them internally?
Yes he is! He is also a great guy! I reached out to him thinking that I had a bad URI. We are both stumped. On a simplex channel works as it should but, not on a repeater programed channel. We tried those settings without success. As far as I know the radio is programed correctly. I shut off the hang timer and disabled the Tx PL tone. No the node is not connected to anything while testing. On a simplex channel it works. I am thinking there might be a setting in the radio but programing the radio is pretty straight forward.
RF to the repeater and internet from the Raspberry PI for the network is all that is connected. So it is CDM750 to RIM-MAXTRAC to Pi with ASL3. RF to the repeater, internet to the server from ASL3 on the Pi. Sorry if my original post was not clear.
Yes you have the correct. The only thing I would add is that the ping ponging continues on the node radio even after the repeater is silent or not transmitting. Its like a loop is created but, audio is still passing from the internet or via RF but the ping ponging continues until I power down the radio.
I have seen similar instances when using Motorola GM300/Maxtrac/CDM etc radios for links.
Sometimes, when the link radio transmits, it will also cause the COS gpio pin to become active. The ASL USB interface may be seeing this and causing the ping-pong effect. Monitor the COS pin with a voltmeter, or watch the COS status in the interface tune cli menu "V" feature.
You can try re-programming the CDM for the opposite polarity on the COS pin, and reconfigure the COS polarity in the interface tune menu setting to match.
It's been a long time since I played with setting up a CDM or GM/Maxtrac radio (I have since moved on to XPR radios for links), but I believe the issue was when setting them for active low, but I could be mistaken. I do recall that flipping the polarity (active high vs active low) solved the issue.
Try setting the radio's COS pin for the opposite polarity. Or try using a different gpio pin for COS. Some of the GPIO pins, while able to be programmed for the same function, have slightly different internal configurations to support different use cases.
Better yet, you should re-enable the hang time and courtesy tone on the repeater itself, and have the repeater transmitter's CTCSS encoder only active when the repeater receiver is active. Then set your link radio for CTCSS squelch and use a gpio pin to feed the CTCSS decoder function to the ASL usb interface. That way, only user audio, and no courtesy tones, IDs, etc, will be passed upstream to other ASL nodes. This would also get around the aforementioned issue, if that is in fact what is causing your issue. It is a much better method to remotely link a repeater to a VOIP system.
Sounds like that's a possible unknown. The CDM would need to be programed differently for simplex use vs as a repeater client (user radio). Double check that you have a channel for simplex and a channel for the repeater both programmed correctly.
Additionally, if two repeaters are in-band linking and leaking IDs or CTs you've got a ping-pong problem.
And while I'm on the subject of in-band linking, the audio is not as good as normal Allstar audio because there is an extra radio involved. You're dealing with all the problems of RF linking that Allstar totally does away with.
EDIT: I forgot to mention another disadvantage; the link won't be full duplex.
Never "in-band" link. The results are never good and 99% of the time it is not set up correctly anyways.
Instead, spend your time and energy researching the establishment of an RF IP solution (Ubiquiti, etc) to get IP availability at the repeater location. You can get a great wireless link up to your repeater site for as little as <$150 with a pair of LiteBeams.
Paying a small monthly bill for an IoT cellular data hotspot is also a popular option.
I think so too! Yes it is still there even with the repeater off. It is either the radio, RIM or config of ASL3. I believe that Scott and I ruled out the RIM and radio. However, I am going to try what @K2CB suggested and see if that makes any difference. Thanks for the help.
I have a friend who is using a CDN-1550 to connect ASL to his repeater. He’s doing an in-band link, kind of, in that there is a dedicated receiver that picks up the CDN-1550, and the CDN-1550 receives from the repeater’s transmitter. The PL is gated, so there is no telemetry from the repeater controller.
The link is not full duplex, but if someone keys the network side of the link, it will go out over the repeater regardless of what else is going on.
It’s one of the best sounding compromised links I’ve heard. The second receiver passes audio from the CDN-1550 de-emphasized, including the PL tone, so the audio is very clean. The repeater puts out a PL for all receivers except that one, and it’s gated.
So, it’s not the best situation, but it’s (almost) transparent, considering there are a bunch of radios in the way, and there is certainly no lack of low-end response, as I have heard on other links, and no extra squelch tails.
All this to say that I’m pretty sure the 750 and 1550 work the same, and there is no pingponging on the odd split channel for the repeater. The dedicated receiver and gated PL makes all the difference in this case.
I didn’t do the radio programming, though, so I don’t know if anything special was done to avoid COS going high when the radio transmits.
Try two nodes on the same server. The main node is set up full duplex with no radio. The second private node connects to your radio and is half duplex. Then connect to main to the private node. I have one set up this way for an RF link to a repeater with no internet and works correctly.