Hello All,
Not sure if this is better in a general industry thread but I figured as most 6.25 FDMA operations are over NXDN and on either Kenwood/EF or ICOM I would just post it here.
Forgive what may be a silly question...
I am moving over a system of about 100 HTs across four sites to NXDN, the vendor we originally worked with before I was involved sold us gear that was NXDN capable but just never switched us over and kept us running 12.5 analog. When I was asked if I knew anything about the system and why it performed poorly comparative to other systems people had used in the past I noted they were not using digital and that was likely holding them back in performance dramatically. I switched one of the main operation channels over to 6.25 NXDN using the center point of the licensed frequency (we were already licensed for the correct designators to do so) and they have really liked the performance on that channel.
Now I find myself looking at a sea of 12.5 analog channels we have setup and wondering if I can really "double" them to make more space out of what we have licensed. On paper I understand that the license from the FCC is ±6.25 kHz from center, so take for example 469.5250 MHz... can I really use 469.521875 MHz and 469.528125 MHz when running 6.25 NXDN?
For anyone who is using this or has done this in the past, I have a few questions...
Is the deviation on NXDN really that tight you can effectively do this? Does NXDN really perform adjacent channel rejection that effectively?
Most of my HTs are new and in good shape, but there are some older ones in the mix, do the transmitters "drift" in accuracy over the years so much that you see issues as they get older with this type of application?
Transmit power is going to be 5W under most circumstances, I have a repeater I may change over to NXDN at some point and I figure I will keep the TX on it far away from everything else to avoid adjacent channel desensitization, but for the HTs running simplex at 5W do I need to worry about that much?
Two of my sites are generally outside of the transmit range HT-HT (hence the repeater for cross site operations) so I also figure I can help avoid some issues by just taking the two 6.25s and placing them at sites away from each other.
Mostly I am just trying to take full advantage of the spectral efficiency of narrow NXDN and not just keep going to the FCC to get more airspace. Hope my question makes sense.
Thanks,
Jack
Not sure if this is better in a general industry thread but I figured as most 6.25 FDMA operations are over NXDN and on either Kenwood/EF or ICOM I would just post it here.
Forgive what may be a silly question...
I am moving over a system of about 100 HTs across four sites to NXDN, the vendor we originally worked with before I was involved sold us gear that was NXDN capable but just never switched us over and kept us running 12.5 analog. When I was asked if I knew anything about the system and why it performed poorly comparative to other systems people had used in the past I noted they were not using digital and that was likely holding them back in performance dramatically. I switched one of the main operation channels over to 6.25 NXDN using the center point of the licensed frequency (we were already licensed for the correct designators to do so) and they have really liked the performance on that channel.
Now I find myself looking at a sea of 12.5 analog channels we have setup and wondering if I can really "double" them to make more space out of what we have licensed. On paper I understand that the license from the FCC is ±6.25 kHz from center, so take for example 469.5250 MHz... can I really use 469.521875 MHz and 469.528125 MHz when running 6.25 NXDN?
For anyone who is using this or has done this in the past, I have a few questions...
Is the deviation on NXDN really that tight you can effectively do this? Does NXDN really perform adjacent channel rejection that effectively?
Most of my HTs are new and in good shape, but there are some older ones in the mix, do the transmitters "drift" in accuracy over the years so much that you see issues as they get older with this type of application?
Transmit power is going to be 5W under most circumstances, I have a repeater I may change over to NXDN at some point and I figure I will keep the TX on it far away from everything else to avoid adjacent channel desensitization, but for the HTs running simplex at 5W do I need to worry about that much?
Two of my sites are generally outside of the transmit range HT-HT (hence the repeater for cross site operations) so I also figure I can help avoid some issues by just taking the two 6.25s and placing them at sites away from each other.
Mostly I am just trying to take full advantage of the spectral efficiency of narrow NXDN and not just keep going to the FCC to get more airspace. Hope my question makes sense.
Thanks,
Jack
