Curious why you couldn’t use, for example, TS1 for repeater input and TS2 for repeater output while using dual receive on all radios talking to the repeater. That way, all input to the repeater is on one time slot and all users are listening to the other time slot. The only issue will be if a receiving station also hears the talking station direct.
We have an SFR repeater model Kydera Emesh installed by radio amateurs. Works very well. There is a different algorithm for setting time slots, the radios are configured to work in a direct channel without specifying a time slot, and the repeater itself is synchronized by time slots
It sounds like that one uses the normal SFR mode I talked about at 3:30 in this video, similar to how most SFRs work. I think that method is better than how the GD-88 does it.
when in cross band and using 2 bands , you would not hear the popping, which is the DMR 4fsk being demodulated because of the lack of isolation. When using the same band you would hear it on the FM side when the frequencies are fairly close. If you have an FM communication test set tune to a freq using DMR and you will it that same popping.
An interesting concept for experimenting with. I know Hytera have had this facility in some of the PD series for a while but I have yet to see anyone testing it outside of the same room.
8:00 I bet this is something that could be solved in a firmware update. Goodness, if my programming cable worked I could even see if the update is out!
Thanks yes interesting Video shows that the gd-88 is an advanced dmr Radio packed with functions and not for the faint hearted it will never be an Anytone 878 ,the dual receive is such a good feature try it with a duplex hotspot using separate time slots.
Hello, I have a question and a slight problem. I have a radioddity gd-88 DMR radio and 2 KENWOOD NX1300 radios. Kenwoods communicate with each other in both directions. Also with radioddity, but when the radioddity is suitable in Kenwood, it is portable, the speaker is slightly humming, but there is no modulation, nothing is independent, what needs to be connected, I will add that CC is the same, timslot is also the same in the repeater function, there is a lot of noise but there is no sound, please help
Thanks for yor interesting explanation about SFR. What do you think if all users using such as dual wacth/dual monitor/dual on/dual stand by radio. So we can set TS1 on A channel, and TS2 on B channel in the same SFR. Or using radio with pseudo trunking feature which is can automatically detect TS transmitting?
Actually pseudo trunk doesn't work with it since it's not dual capacity direct mode. Hytera did have DCDM previously but were forced to remove it when Motorola sued them. I'm not really sure how all the other Chinese manufacturers are getting away with it, unless they're licencing the tech from Motorola. Using dual monitor radios should work similarly to using a scan list as described in the video. So in theory I think it should work fine. You'll still have the other issues though like very low audio and randomly not transmitting any audio.
Two questions for you: 1. Regarding the Motorola radio shown in your video, I don't see the "talkaround icon". This means the current channel of the MOTO is a repeater channel. For a repeater channel, how is it possible for you to key up without a repeater actually there? 2. Regarding the DR-880UV shown in your video, you just showed that the Rx frequency and Tx frequency of 434.2 MHz. Since the Rx and Tx frequency is the same, it is therefore a talkaround channel. For a talkaround channel, the setting of time slot doesn't make any difference. That is, if you transmit on TS1, you can still receive on TS2, and vice versa.
Good questions. I'm going to have to write a pretty detailed answer! I don't think talkaround means what you think it means though. Normally talkaround is used to mean talking on a repeater's frequency when the repeater is out of range or not working. For a simplex channel, that is not the same thing as talkaround. It's just using a simplex channel. I had a look at the manual for the radio though and it does show that icon as "talkaround". I'm not sure why they've done that because it is rather confusing, but the icon basically seems to mean you're operating on a simplex frequency that's not through a repeater. It shows up for analogue and DMR simplex channels, but does not show up on DCDM channels. I don't know why they haven't set it to show on DCDM channels, maybe it should do. Maybe they reasoned that a DCDM channel can never be a repeater channel so it's not necessary, but the radio user doesn't know this because they're normally just given the radio already programmed by someone else and probably have no idea what DCDM even is, so this wouldn't be a very valid design decision. So it seems to be a bit of an inconsistency in their design choices to me. 1. The channel being used was a dual capacity direct mode channel, so it cannot be a repeater channel (at least, normally). In general you don't have repeaters using DCDM. This Kydera is the exception (along with a small number of other chinese radios I think). I can key up without a repeater being there because the radio doesn't expect to be on a repeater. As far as the DP4800 is concerned, it's just transmitting on a DCDM channel. Someone else is talking on the other timeslot at the same time which is fine. No repeater around. What's actually happening is the Kydera is repeating it back out on the other timeslot, but the DP4800 has no idea that's what's happening. 2. The whole point of this video is that it's a SINGLE frequency repeater, so naturally the TX and RX frequency will be the same. On normal simplex channels on DMR (ones that are not DCDM channels) then you're right, the timeslots are ignored because there's no reference by which to determine which timeslot is in use. However, DCDM's purpose is to synchronise the radios so that you can use both timeslots. Thus on a DCDM channel, you can use both timeslots as I'm doing in this video. Btw, DCDM channels are always simplex. The radio actually greys out the TX frequency when you set a channel to DCDM - it won't even let you try to set different TX and RX frequencies. Hope that helps.
@@radiosification This helps a lot! Personally I don't see any difference between a simplex channel and a talkaround channel. They all mean having Rx freq=Tx freq. To further differentiate one from another, simplex channel, for me, is just a random channel which Tx freq=Rx freq, such as FRS radio channels, test channels, etc. Talkaround channel, on the other hand, may refer to a repeater channel BUT you just transmit at the downlink frequency of the repeater channel, while maintaining the Rx side the same. Usually there should be a programmable button to allow toggling between talkaround mode and repeater mode. A talkaround mode is, indeed, technically a simplex channel. Regarding the MOTO operating in DCDM mode, does this mode require an additional "base radio", which typically is a mobile radio, to provide the syncing of time slot, as stipulated in the description of MOTO CPS? If yes, do radios from other brands also require such a base radio? If no, do the MOTO radios communicate separately on TS1 and TS2 respectively, when the DCDM mode is turned on? In this case, what frames the time slots?
They all work the same in DCDM mode. You don't need a base radio, any radio can work as the "timing leader" as long as it's set as eligible to be the timing leader in the CPS. The radios on the frequency (both timeslots together, not separately) will negotiate and pick one to be the timing leader, which will decide on sync. I don't see that setting on the chinese models so maybe they don't allow you to select whether the radio is preferred, eligible or not eligible and just have one option always set.
I was thinking of getting one of these to test the sfr. Me and a few mates run the opengd77 so this could work. My idea is we tx on ts1 and have the ts scan feature enabled so it will hear the output when it’s on ts2. Obviously the only issue there is if you’re close to the tx radio it may get confused on what ts to listen to but in my case, we won’t be too close.
@@radiosification I’m not sure but surely it won’t be needed tho ? I tx on ts1 so the repeater hears that and re-transmits on ts2. The receiving radio will be in promiscuous mode so will hear any ts - switching to ts2 to hear the repeaters transmission.
@@samsalloway7412 no the SFR on this radio uses dcdm. If your radio transmitting in is not using dcdm then the SFR doesn't hear it. It doesn't work like a normal repeater
Radios like the Anytone D-AT878UV series DCDM with split timeslots so do not suffer the drawback demonstrated with the Motorola and other mobile stations in the video. The Anytone can operate in DCDM transmitting on TS1 and receiving on TS2. To do this you need to configure DCDM for TS Split. While there is not an explicit use case in the ETSI DMR standard illustrating this it is an inherent capability which some suppliers have implemented and others haven't. Nonetheless a very good video and presentation of the problem.
Thanks. In a later video I showed the hytera's single frequency repeater, which has a much better design. I don't know why Kydera didn't copy that design instead of this disaster they call a single frequency repeater!
"it's almost the only DMR Radio that has sold the most Radios within the last 5 years!" Have you got a source for that or did you just make it up? As far as I can see based on activity online, it's not actually a very popular radio at all (rightly so, it's full of bugs).
Motorola have own way of implementing this mode which is programmable in radios which radios from other brands haven't. We don't know if the SFR is not working does radios will still comunicate in simplex mode? Speaking for only Motorola SFR system I. E. Extended range direct mode ...
Great video! I'm about to get my licence HB9. I was wondering for different reasons, whether the alincoAlinco 1226 DJ-MD-5-GPS DMR VHF/UHF is relevant in a mountain region, with sporadic use in city? What do you think about! My choice is mainly oriented due to my untrust toward chinease products in General. That's why I preferred. Japanese brand specially as they have shifted their production to Japan. Let me know your thoughts! Thanks and cheers from 🇨🇭
I have a comparison of DMR handhelds on my blog and I remember that radio being on there. Can't remember what I said about it now but I've barely heard of anyone using it so take from that what you will. I'm not sure which radio you buy will make much difference in terms of mountain/city use. Radio is radio. As long as you have an antenna that works well for the frequency you're using, any of the popular DMR handhelds should work okay.
@@radiosification thank you again for help and your opinion! I will give it a look! This is really helpful specially as I am Newby here and need as much information as possible to make the right choice! Wish you a happy end of the years celebrations 🍾 and all the best!
How many handhelds have you got now bud? I'm thinking a lot...its an addiction. A lot of business radio use this system here where I am in Scotland. There are many DCDM Linked/shared repeaters and they overlap areas.. Because there are three main DMR suppliers here they all seem to allocate the same or close by TGs... Which makes it difficult to identify what is what. So if I was looking for a DMR handheld to scan with which would you recommend?
Quite a lot. I haven't counted. Are you sure there are DCDM repeaters? That's an extremely uncommon thing and I don't think any exist that could be linked.
Hi , to be clear. 1- Is this radio working good as DMR repeater using 2 frecuencies (Tx and Rx)? 2- Will this RE- TRANSMIT radios info, as ID name or other? Thank you
1. Do you mean single band or cross band? It will work in either but it will probably be desensitized if you try to do it as a single band repeater (not including single frequency repeater). It won't work with most DMR radios though because if you use two frequencies they expect a proper repeater which transmits so they can sync up. 2. I can't remember. Maybe I showed it in the video. If I have to guess I think probably not. I think it shows the information from the repeating radio, so the GD-88.
-? Will this radio Transmit the radios Id or name etc, OR IT WILL TRANSMIT gd88 ID. Can we see who is calling tru this repeater or no.? Thank u DMR and this GD88 IS RIDICULOUS CONFUSING
"Will this radio Transmit the radios Id or name etc, OR IT WILL TRANSMIT gd88 ID. Can we see who is calling tru this repeater or no.?" Yes it will transmit the ID you set, same with all DMR radios. If you're asking about talker alias which the radio now has, you can also set that.
I started to hate DMR is like FIGTHING TO COMUNICATE FREE to the comunity. programming is like they do not want us to transmit a lot of adjusttments for everithing
That's why I don't even mess with digital anything I'm an analog person and I stayed to that I will never use DMR for anything it's analog or nothing in my case and I don't have to worry about nonsense programming either it's too complicated and I don't have any time to mess with that shit‼️‼️‼️‼️‼️‼️‼️‼️
Fair enough. The programming is not actually complicated once you understand it. I find it really easy to program digital channels now. And there are some cool features DMR has that are fun to play with. If you just want easy to use communications and don't care about other features then analog works well. Also this radio is not a good one to judge DMR from. It's not a very good radio tbh because the firmware has so many issues. If you get a good quality DMR radio like a Motorola then it works great.
Curious why you couldn’t use, for example, TS1 for repeater input and TS2 for repeater output while using dual receive on all radios talking to the repeater. That way, all input to the repeater is on one time slot and all users are listening to the other time slot. The only issue will be if a receiving station also hears the talking station direct.
We have an SFR repeater model Kydera Emesh installed by radio amateurs. Works very well. There is a different algorithm for setting time slots, the radios are configured to work in a direct channel without specifying a time slot, and the repeater itself is synchronized by time slots
It sounds like that one uses the normal SFR mode I talked about at 3:30 in this video, similar to how most SFRs work. I think that method is better than how the GD-88 does it.
yes it is true, the standard sfr method is used.
when in cross band and using 2 bands , you would not hear the popping, which is the DMR 4fsk being demodulated because of the lack of isolation. When using the same band you would hear it on the FM side when the frequencies are fairly close. If you have an FM communication test set tune to a freq using DMR and you will it that same popping.
Thanks for your input
An interesting concept for experimenting with. I know Hytera have had this facility in some of the PD series for a while but I have yet to see anyone testing it outside of the same room.
@@radiosification Sounds good, I look forward to it!
I have a PD982 and have tested it with Hytera, Motorola, Kenwood, Anytone radios. It works well with those select radios.
8:00 I bet this is something that could be solved in a firmware update. Goodness, if my programming cable worked I could even see if the update is out!
Interesting stuff Ben! Cheers
Thanks Lewis!
Thanks yes interesting Video shows that the gd-88 is an advanced dmr Radio packed with functions and not for the faint hearted it will never be an Anytone 878 ,the dual receive is such a good feature try it with a duplex hotspot using separate time slots.
Have a look here:th-cam.com/video/EnkW3ywOacc/w-d-xo.html
Thanks for sharing
Hello, I have a question and a slight problem. I have a radioddity gd-88 DMR radio and 2 KENWOOD NX1300 radios. Kenwoods communicate with each other in both directions. Also with radioddity, but when the radioddity is suitable in Kenwood, it is portable, the speaker is slightly humming, but there is no modulation, nothing is independent, what needs to be connected, I will add that CC is the same, timslot is also the same in the repeater function, there is a lot of noise but there is no sound, please help
Thanks for yor interesting explanation about SFR. What do you think if all users using such as dual wacth/dual monitor/dual on/dual stand by radio. So we can set TS1 on A channel, and TS2 on B channel in the same SFR. Or using radio with pseudo trunking feature which is can automatically detect TS transmitting?
Actually pseudo trunk doesn't work with it since it's not dual capacity direct mode. Hytera did have DCDM previously but were forced to remove it when Motorola sued them. I'm not really sure how all the other Chinese manufacturers are getting away with it, unless they're licencing the tech from Motorola.
Using dual monitor radios should work similarly to using a scan list as described in the video. So in theory I think it should work fine. You'll still have the other issues though like very low audio and randomly not transmitting any audio.
@@radiosification I see. Thank you very much for your answer, and goodluck! 👍
Two questions for you:
1. Regarding the Motorola radio shown in your video, I don't see the "talkaround icon". This means the current channel of the MOTO is a repeater channel. For a repeater channel, how is it possible for you to key up without a repeater actually there?
2. Regarding the DR-880UV shown in your video, you just showed that the Rx frequency and Tx frequency of 434.2 MHz. Since the Rx and Tx frequency is the same, it is therefore a talkaround channel. For a talkaround channel, the setting of time slot doesn't make any difference. That is, if you transmit on TS1, you can still receive on TS2, and vice versa.
Good questions. I'm going to have to write a pretty detailed answer!
I don't think talkaround means what you think it means though. Normally talkaround is used to mean talking on a repeater's frequency when the repeater is out of range or not working. For a simplex channel, that is not the same thing as talkaround. It's just using a simplex channel.
I had a look at the manual for the radio though and it does show that icon as "talkaround". I'm not sure why they've done that because it is rather confusing, but the icon basically seems to mean you're operating on a simplex frequency that's not through a repeater. It shows up for analogue and DMR simplex channels, but does not show up on DCDM channels. I don't know why they haven't set it to show on DCDM channels, maybe it should do. Maybe they reasoned that a DCDM channel can never be a repeater channel so it's not necessary, but the radio user doesn't know this because they're normally just given the radio already programmed by someone else and probably have no idea what DCDM even is, so this wouldn't be a very valid design decision. So it seems to be a bit of an inconsistency in their design choices to me.
1. The channel being used was a dual capacity direct mode channel, so it cannot be a repeater channel (at least, normally). In general you don't have repeaters using DCDM. This Kydera is the exception (along with a small number of other chinese radios I think). I can key up without a repeater being there because the radio doesn't expect to be on a repeater. As far as the DP4800 is concerned, it's just transmitting on a DCDM channel. Someone else is talking on the other timeslot at the same time which is fine. No repeater around. What's actually happening is the Kydera is repeating it back out on the other timeslot, but the DP4800 has no idea that's what's happening.
2. The whole point of this video is that it's a SINGLE frequency repeater, so naturally the TX and RX frequency will be the same. On normal simplex channels on DMR (ones that are not DCDM channels) then you're right, the timeslots are ignored because there's no reference by which to determine which timeslot is in use. However, DCDM's purpose is to synchronise the radios so that you can use both timeslots. Thus on a DCDM channel, you can use both timeslots as I'm doing in this video. Btw, DCDM channels are always simplex. The radio actually greys out the TX frequency when you set a channel to DCDM - it won't even let you try to set different TX and RX frequencies.
Hope that helps.
@@radiosification This helps a lot! Personally I don't see any difference between a simplex channel and a talkaround channel. They all mean having Rx freq=Tx freq. To further differentiate one from another, simplex channel, for me, is just a random channel which Tx freq=Rx freq, such as FRS radio channels, test channels, etc. Talkaround channel, on the other hand, may refer to a repeater channel BUT you just transmit at the downlink frequency of the repeater channel, while maintaining the Rx side the same. Usually there should be a programmable button to allow toggling between talkaround mode and repeater mode. A talkaround mode is, indeed, technically a simplex channel.
Regarding the MOTO operating in DCDM mode, does this mode require an additional "base radio", which typically is a mobile radio, to provide the syncing of time slot, as stipulated in the description of MOTO CPS? If yes, do radios from other brands also require such a base radio? If no, do the MOTO radios communicate separately on TS1 and TS2 respectively, when the DCDM mode is turned on? In this case, what frames the time slots?
They all work the same in DCDM mode. You don't need a base radio, any radio can work as the "timing leader" as long as it's set as eligible to be the timing leader in the CPS. The radios on the frequency (both timeslots together, not separately) will negotiate and pick one to be the timing leader, which will decide on sync. I don't see that setting on the chinese models so maybe they don't allow you to select whether the radio is preferred, eligible or not eligible and just have one option always set.
@@radiosification thanks!
I was thinking of getting one of these to test the sfr. Me and a few mates run the opengd77 so this could work. My idea is we tx on ts1 and have the ts scan feature enabled so it will hear the output when it’s on ts2. Obviously the only issue there is if you’re close to the tx radio it may get confused on what ts to listen to but in my case, we won’t be too close.
Does the Opengd77 firmware have dual capacity direct mode? If not it won't work
@@radiosification I’m not sure but surely it won’t be needed tho ? I tx on ts1 so the repeater hears that and re-transmits on ts2. The receiving radio will be in promiscuous mode so will hear any ts - switching to ts2 to hear the repeaters transmission.
@@samsalloway7412 no the SFR on this radio uses dcdm. If your radio transmitting in is not using dcdm then the SFR doesn't hear it. It doesn't work like a normal repeater
@@radiosification have you got an email I can contact you on mate ?
@@samsalloway7412 yeah it's my username on TH-cam at outlook.com
Radios like the Anytone D-AT878UV series DCDM with split timeslots so do not suffer the drawback demonstrated with the Motorola and other mobile stations in the video. The Anytone can operate in DCDM transmitting on TS1 and receiving on TS2. To do this you need to configure DCDM for TS Split. While there is not an explicit use case in the ETSI DMR standard illustrating this it is an inherent capability which some suppliers have implemented and others haven't. Nonetheless a very good video and presentation of the problem.
Thanks. In a later video I showed the hytera's single frequency repeater, which has a much better design. I don't know why Kydera didn't copy that design instead of this disaster they call a single frequency repeater!
GD-88 is a great radio everyone should own it and actually it's almost the only DMR Radio that has sold the most Radios within the last 5 years!
"it's almost the only DMR Radio that has sold the most Radios within the last 5 years!"
Have you got a source for that or did you just make it up? As far as I can see based on activity online, it's not actually a very popular radio at all (rightly so, it's full of bugs).
Motorola have own way of implementing this mode which is programmable in radios which radios from other brands haven't. We don't know if the SFR is not working does radios will still comunicate in simplex mode? Speaking for only Motorola SFR system I. E. Extended range direct mode ...
Yes I believe they will because my motorola radio could talk to other DMR radios on simplex when this mode was enabled.
It would be good if radios have pseudo trunking mode so the radio will receive on two slots, but will listen only own rx group or group list.
Great video! I'm about to get my licence HB9. I was wondering for different reasons, whether the alincoAlinco 1226 DJ-MD-5-GPS DMR VHF/UHF is relevant in a mountain region, with sporadic use in city? What do you think about! My choice is mainly oriented due to my untrust toward chinease products in General. That's why I preferred. Japanese brand specially as they have shifted their production to Japan. Let me know your thoughts! Thanks and cheers from 🇨🇭
I have a comparison of DMR handhelds on my blog and I remember that radio being on there. Can't remember what I said about it now but I've barely heard of anyone using it so take from that what you will.
I'm not sure which radio you buy will make much difference in terms of mountain/city use. Radio is radio. As long as you have an antenna that works well for the frequency you're using, any of the popular DMR handhelds should work okay.
@@radiosification thank you again for help and your opinion! I will give it a look! This is really helpful specially as I am Newby here and need as much information as possible to make the right choice!
Wish you a happy end of the years celebrations 🍾 and all the best!
Good luck with your licence!
How many handhelds have you got now bud? I'm thinking a lot...its an addiction.
A lot of business radio use this system here where I am in Scotland. There are many DCDM Linked/shared repeaters and they overlap areas.. Because there are three main DMR suppliers here they all seem to allocate the same or close by TGs... Which makes it difficult to identify what is what.
So if I was looking for a DMR handheld to scan with which would you recommend?
Quite a lot. I haven't counted.
Are you sure there are DCDM repeaters? That's an extremely uncommon thing and I don't think any exist that could be linked.
Can the radio crossband from analog to c4fm and vice versa or it just works with DMR/analog or DMR/DMR?
No, the radio does not support any other digital modes. DMR and FM only.
Hi , to be clear.
1- Is this radio working good as DMR repeater using 2 frecuencies (Tx and Rx)?
2- Will this RE- TRANSMIT radios info, as ID name or other? Thank you
1. Do you mean single band or cross band? It will work in either but it will probably be desensitized if you try to do it as a single band repeater (not including single frequency repeater). It won't work with most DMR radios though because if you use two frequencies they expect a proper repeater which transmits so they can sync up.
2. I can't remember. Maybe I showed it in the video. If I have to guess I think probably not. I think it shows the information from the repeating radio, so the GD-88.
-? Will this radio Transmit the radios Id or name etc, OR IT WILL TRANSMIT gd88 ID. Can we see who is calling tru this repeater or no.? Thank u
DMR and this GD88 IS RIDICULOUS CONFUSING
"Will this radio Transmit the radios Id or name etc, OR IT WILL TRANSMIT gd88 ID. Can we see who is calling tru this repeater or no.?"
Yes it will transmit the ID you set, same with all DMR radios. If you're asking about talker alias which the radio now has, you can also set that.
@@radiosification sorry I mean to say RE-TRANSMIT the other radios ID /info when is used as dmr repeater. ??
If all the radios had promiscuous mode with this get around that?
Not necessarily because on many radios, promiscuous mode is only for talk group.
I started to hate DMR is like FIGTHING TO COMUNICATE FREE to the comunity. programming is like they do not want us to transmit a lot of adjusttments for everithing
That's why I don't even mess with digital anything I'm an analog person and I stayed to that I will never use DMR for anything it's analog or nothing in my case and I don't have to worry about nonsense programming either it's too complicated and I don't have any time to mess with that shit‼️‼️‼️‼️‼️‼️‼️‼️
Fair enough. The programming is not actually complicated once you understand it. I find it really easy to program digital channels now. And there are some cool features DMR has that are fun to play with. If you just want easy to use communications and don't care about other features then analog works well.
Also this radio is not a good one to judge DMR from. It's not a very good radio tbh because the firmware has so many issues. If you get a good quality DMR radio like a Motorola then it works great.