XPR 7550e ... just wow...

[123]

On 12/21/2020 at 10:53 AM, jerrym58 said:

I'll just point this out in case you care.  The XPR7550e is not Part 95 certified but it's quality far exceeds any GMRS-only radio I have ever come across.  For that reason, for me using the XPR-7550e for GMRS is an acceptable risk.  This is just my personal opinion and you have to decide for yourself whether or not this is acceptable for you.   That radio can also do ham frequencies with no problem.  The FCC SHOULD be happy about this because there is a greater likelihood that your emissions will conform to the FCC part 95 rules but in reality they probably just don't care unless they come after you for some other abuse and just want to pile on more fines.  I have never heard of anyone fined for using a non-certified radio that conforms to Part 95 emissions where that was the only offense.  The FCC generally only responds to complaints.  

The FCC has already stated that as long as the radio is certified Part 90 that it is fine because the cert. meets or exceeds part 95 certification.

Also you are not required to do 20, FCC only states maximum,  therefore 12.5 is acceptable and in my option 12.5 should be standard across the board including ham. Many GMRS repeaters are already 12.5 

[marcspaz]

5 minutes ago, 123 said:

The FCC has already stated that as long as the radio is certified Part 90 that it is fine because the cert. meets or exceeds part 95 certification.

Also you are not required to do 20, FCC only states maximum,  therefore 12.5 is acceptable and in my option 12.5 should be standard across the board including ham. Many GMRS repeaters are already 12.5 

 

That second paragraph doesn't make any sense to me.  Why would you want to restrict everything, including Ham, to 12.5KHz? 

[Lscott]

6 hours ago, marcspaz said:

 

That second paragraph doesn't make any sense to me.  Why would you want to restrict everything, including Ham, to 12.5KHz? 

I think the FCC, and other agencies in other countries, will move most users to 6.25KHz, most likely digital, when the technology is easy and cheap enough. There was a post somewhere I read where the FCC considers 12.5KHz as an intermediate step before moving to the narrower 6.25KHz bandwidth. If you don't have a radio that can do 6.25KHz now I would start looking for one.

That's why you see mention of the TDMA method used for DMR as being 6.25KHz "equivalent"  bandwidth even though the channel bandwidth is 12.5KHz.

NXDN uses FDMA and can do 12.5KHz and 6.25KHz bandwidth, both in digital mode, depending on the VOCODER data rate used so it's already when the ultra narrow bandwidth is mandated by the FCC.

https://en.wikipedia.org/wiki/NXDN

[gortex2]

When the ICOM came out with the early NXDN stuff I put one on a service monitor and was really surprised it hit that 6.25 mark. One of the systems I did took 4 UHF channels and broke them up to give them 8 talk paths. I still have a few of the ICOMS in my storage unit as we had hoped to move SAR towards that but the P25 was too prevalent to switch.

[Lscott]

11 minutes ago, gortex2 said:

When the ICOM came out with the early NXDN stuff I put one on a service monitor and was really surprised it hit that 6.25 mark. One of the systems I did took 4 UHF channels and broke them up to give them 8 talk paths. I still have a few of the ICOMS in my storage unit as we had hoped to move SAR towards that but the P25 was too prevalent to switch.

My question about using two adjacent 6.25KHz channels, or even 12.5KHz channels, is how steep are the filter skirts in the radio's IF section. They typically use cheap ceramic resonator type filters.  

If they're not extremely steep the attenuation of the adjacent channels will be noticeably degraded because the IF filter pass response would still be fairly high as it overlaps the adjacent channel's bandwidth boundary.

For example you might see a selectivity specification of negative 60db at 30KHz using a 16KHz wide signal, 5KHz deviation with 3KHz audio. That would imply the filter skirt's roll offs are 14KHz total for both sides. Reducing the signal bandwidth to 11KHz, 2.5KHz deviation with 3KHz audio, and adding in the same filter skirt bandwidth, roll off is the same but pass band is narrower, results in a possible performance of negative 60 db at 25KHz. The total bandwidth is less but it's not as narrow as  you would first assume.  

For mobile/base radios there is enough room to put in better analog filters with steeper roll offs. However in portable radios' HT's, PCB area is limited. Perhaps replacing the analog filters with a high order DSP based one at a lower IF frequency might work. You can design a DSP filter in hardware using an FPGA which would give better performance than a DSP type micro could provide.

Any claims that going to a bandwidth of half of the former value the number of channels can be doubled I'm very skeptical about it without some major improvement in the filter technology IMHO. 

[gortex2]

Agree. I was surprised at how well it worked. The one site had 4 repeaters using 4 6.25 splits. Repeaters were in different areas of the campus and they never seemed to have issues. I think if they were all at one site there would be not a way to make it work without serious cash in filtering. I'll have to try to dig out my old ones and run some tests on the Anritzu with them.

 

[Lscott]

4 hours ago, gortex2 said:

Agree. I was surprised at how well it worked. The one site had 4 repeaters using 4 6.25 splits. Repeaters were in different areas of the campus and they never seemed to have issues. I think if they were all at one site there would be not a way to make it work without serious cash in filtering. I'll have to try to dig out my old ones and run some tests on the Anritzu with them.

 

That would be a very interesting test. I would like to see just how much adjacent channel rejection the radios really have.

The transmit bandwidth can be controlled through careful pulse shaping while in digital mode. That's why you see mention of such things as GMSK modulation for some digital modes.

https://en.wikipedia.org/wiki/Gaussian_filter

https://www.electronics-notes.com/articles/radio/modulation/what-is-gmsk-gaussian-minimum-shift-keying.php

https://urgentcomm.com/2001/04/01/does-the-digital-radio-standard-come-up-short/

[gman1971]

I think we are a long way from 6.25kHz. The next XPR7550e replacement is upon us and it is likely to be MotoTRBO DMR 12.5kHz... so if Motorola is sticking to 12.5kHz on their DMR flagship radios, it is highly unlikely that they'll mandate 6.25kHz any time soon. In 10 years? Maybe, but not now.

As for the 6.25 spacing 4 pathways claim, well, please forgive if I am very skeptical, as I have serious doubts you can run 4 concurrent 6.25kHz channels on any substantial amount of power without either blowing the other radios front ends or desensing them so bad they can't hear a thing.

TDMA can be implemented over any bandwidth, 25khz, 12.5kHz, 6.25kHz, and while it has other set of problems, doing DCDM Simplex, running two concurrent voice channels on the same freq doesn't require special hardware, or TETRA, running 4 concurrent conversations...

G.

[Lscott]

2 hours ago, gman1971 said:

I think we are a long way from 6.25kHz. The next XPR7550e replacement is upon us and it is likely to be MotoTRBO DMR 12.5kHz... so if Motorola is sticking to 12.5kHz on their DMR flagship radios, it is highly unlikely that they'll mandate 6.25kHz any time soon. In 10 years? Maybe, but not now.

As for the 6.25 spacing 4 pathways claim, well, please forgive if I am very skeptical, as I have serious doubts you can run 4 concurrent 6.25kHz channels on any substantial amount of power without either blowing the other radios front ends or desensing them so bad they can't hear a thing.

TDMA can be implemented over any bandwidth, 25khz, 12.5kHz, 6.25kHz, and while it has other set of problems, doing DCDM Simplex, running two concurrent voice channels on the same freq doesn't require special hardware, or TETRA, running 4 concurrent conversations...

G.

Yeah, I'm also VERY skeptical running adjacent channels at 6.25KHz bandwidth. Even the wider 12.5KHz I wouldn't believe either. Even Ham HT's with two pair of stations close to each other at a 25KHz channel separation doesn't work out too well either.   

[tweiss3]

9 hours ago, gman1971 said:

I think we are a long way from 6.25kHz. The next XPR7550e replacement is upon us and it is likely to be MotoTRBO DMR 12.5kHz... so if Motorola is sticking to 12.5kHz on their DMR flagship radios, it is highly unlikely that they'll mandate 6.25kHz any time soon. In 10 years? Maybe, but not now.

As for the 6.25 spacing 4 pathways claim, well, please forgive if I am very skeptical, as I have serious doubts you can run 4 concurrent 6.25kHz channels on any substantial amount of power without either blowing the other radios front ends or desensing them so bad they can't hear a thing.

TDMA can be implemented over any bandwidth, 25khz, 12.5kHz, 6.25kHz, and while it has other set of problems, doing DCDM Simplex, running two concurrent voice channels on the same freq doesn't require special hardware, or TETRA, running 4 concurrent conversations...

G.

 

6 hours ago, Lscott said:

Yeah, I'm also VERY skeptical running adjacent channels at 6.25KHz bandwidth. Even the wider 12.5KHz I wouldn't believe either. Even Ham HT's with two pair of stations close to each other at a 25KHz channel separation doesn't work out too well either.   

Yea, my VHF radio at home doesn't like my 1W APRS beacon that is 28' away from the base station antenna (144.39MHz to 147.27MHz). Though, looking at the sites for some local P25 P2 systems, they have frequencies as close as 0.275MHz, however, appropriate TX combiners and filters/cavities it wouldn't be an issue at all. 

I read somewhere that P25P2 was supposed to be FDMA (true 6.25 individual channels), but ended up TDMA, which is still ok since it is a 6.25 equivalent. I believe NXDN is the only true FDMA 6.25 mode available, and works well for the railroads, but it's not common on the public safety side (my school district uses it on VHF for the busses). 

As far as TETRA having 4 paths on one frequency, it does, but it is also TDMA in a 25k frequency, so basically 2 DMR stacked next to each other in 1 frequency.

Long and short of it, I don't think DMR as we know it is going away. If they stopped acknowledging it as a 6.25 equivalent, then they would have to shut down P25 as well, and that won't happen.

[Lscott]

12 minutes ago, tweiss3 said:

I read somewhere that P25P2 was supposed to be FDMA (true 6.25 individual channels), but ended up TDMA, which is still ok since it is a 6.25 equivalent. I believe NXDN is the only true FDMA 6.25 mode available, and works well for the railroads, but it's not common on the public safety side (my school district uses it on VHF for the busses).

I believe P25 Phase 2 is TDMA for trunking systems only. I don't believe it is used for any simplex communications. That is fine with me since the two radios I have are Phase 1 only and my use would be on Ham radio.

With luck the public safety agencies will all switch to Phase 2 and dump their Phase 1 radios. The old Phase 1 radios may show up more frequently on the used market for reasonable prices.

I've also seen a few references on RadioReference.com where NXDN was used by a few schools.

For DMR, sooner or later I think we'll see it as a legal mode on GMRS.

A close relative to DMR is TETRA. I don't think that's used anyplace in the US.

https://en.wikipedia.org/wiki/Terrestrial_Trunked_Radio

[tweiss3]

5 minutes ago, Lscott said:

I believe P25 Phase 2 is TDMA for trunking systems only. I don't believe it is used for any simplex communications. That is fine with me since the two radios I have are Phase 1 only and my use would be on Ham radio.

With luck the public safety agencies will all switch to Phase 2 and dump their Phase 1 radios. The old Phase 1 radios may show up more frequently on the used market for reasonable prices.

I've also seen a few references on RadioReference.com where NXDN was used by a few schools.

For DMR, sooner or later I think we'll see it as a legal mode on GMRS.

A close relative to DMR is TETRA. I don't think that's used anyplace in the US.

https://en.wikipedia.org/wiki/Terrestrial_Trunked_Radio

Correct, P25P2 requires trunking/data channel to synchronize, so simplex flips back to P1 at 12.5kHz.

The NXDN sound darn good on VHF, especially since my district has the lowest density due to being interwoven in the national parks system, our footprint is huge.

I did find another school system that is low power, 4 site, 5 frequency DMR, but uses only 2 talkgroups (busses and facility/maintenance). They sounded good too, but their footprint is tiny and odd shaped (hence the number of sites.

The real problem is there isn't any good current commercial equipment that the FCC has given Part 95 approval for. I'd love to see a current lineup get the stamp. Sooner or later, the EOL stuff is going to be boat anchors.

 

[Lscott]

2 minutes ago, tweiss3 said:

Correct, P25P2 requires trunking/data channel to synchronize, so simplex flips back to P1 at 12.5kHz.

The NXDN sound darn good on VHF, especially since my district has the lowest density due to being interwoven in the national parks system, our footprint is huge.

I did find another school system that is low power, 4 site, 5 frequency DMR, but uses only 2 talkgroups (busses and facility/maintenance). They sounded good too, but their footprint is tiny and odd shaped (hence the number of sites.

The real problem is there isn't any good current commercial equipment that the FCC has given Part 95 approval for. I'd love to see a current lineup get the stamp. Sooner or later, the EOL stuff is going to be boat anchors.

 

NXDN and P25 both use the AMBE+2 codec so If you like how NXDN sounds it should be the same audio quality on P25.

[tweiss3]

12 minutes ago, Lscott said:

NXDN and P25 both use the AMBE+2 codec so If you like how NXDN sounds it should be the same audio quality on P25.

As does the XPR series radios for DMR. It's also why the Kenwood NX radios can support all 3 with just key changes.

[gman1971]

I wish Motorola would do the same, P25/DMR, the APX900 and the XPR7550e SMA are basically the same radio... with different firmware... I am sure someone in a decade, when these XPR7550e ares all EOL someone will come up with a way to enable P25 on them...

The reason why I like XPR over the NX is because the RX audio leveling and the noise suppressor. I like to hear the voice only, not some random stuff behind, etc. You really get spoiled quick to those features..., and you once you go in, you can never come out...

TETRA being 25kHz makes it problematic to use in the US except for amateur bands.

G.

[Lscott]

TETRA is a 4 slot TDMA so it can do 4 effective 6.25KHz channels on a 25KHz wide one.

[PACNWComms]

16 minutes ago, gman1971 said:

The reason why I like XPR over the NX is because the RX audio leveling and the noise suppressor.

I just added options 440/441/640 to an Aeroflex 3920 for NXDN/Kenwood NXDN/Autotest II NXDN respectively, for an oddball science project for a customer. Viavi/Aeroflex messed up the license files between five test sets, but one was correct. I cringe as a former engineer for Zetron when it was part of the JVC/Kenwood Group, as NXDN and 5000 series Kenwood radios always had issues (hired too many Microsoft transplants) with many software bug fixes and patches being necessary (more so than Motorola at least). If you buy Kenwood, order what you need as adding features or unlocking them with a license may become a problem at a future date....see Microsoft part of comment.

As for the XPR7550e, great little radios, but there is a Hex problem in every version of CPS 2.0 which requires some changes in either: the radio programming and/or Provisioning Manager if you use aliasing, or in one version you must skip any hex ID that contains the letter "E"

[gman1971]

29 minutes ago, PACNWComms said:

I just added options 440/441/640 to an Aeroflex 3920 for NXDN/Kenwood NXDN/Autotest II NXDN respectively, for an oddball science project for a customer. Viavi/Aeroflex messed up the license files between five test sets, but one was correct. I cringe as a former engineer for Zetron when it was part of the JVC/Kenwood Group, as NXDN and 5000 series Kenwood radios always had issues (hired too many Microsoft transplants) with many software bug fixes and patches being necessary (more so than Motorola at least). If you buy Kenwood, order what you need as adding features or unlocking them with a license may become a problem at a future date....see Microsoft part of comment.

As for the XPR7550e, great little radios, but there is a Hex problem in every version of CPS 2.0 which requires some changes in either: the radio programming and/or Provisioning Manager if you use aliasing, or in one version you must skip any hex ID that contains the letter "E"

 

Hats off, impressive analyzer... maybe some day I'll be able to afford one. 

Yeah, as for the Microsoft... I know exactly the feeling, that is why I am staying on Windows 7. I have a machine that should last me no problem to the end of the decade, if not more, for what I need to do with it; and then, I'll see if M$$ has gotten their heads out of their rear ends with Windows 12 or 13, or whatever, or even if its even still in business... LOL

Yep, XPR7550e is where its at IMO. I am running 2.09 on the entire fleet, no plans to upgrade to anything beyond that. I plan on keeping this radios until there are no parts available for them.

With that said, the inevitable replacement for the XPR7550e is coming out in 2 weeks . I'll reserve judgement on the new radio until there are multiple reviews on it, but the fact that it won't run the trusty 2.09 fw is already a con, as it will make me, for the first time in 2 years, have to use 2 CPS programs. The most important part, IMO, the receiver, I don't expect it to improve drastically, if at all; not given the fact that the new MotoTRBO XPR ION uses the same exact receiver as the XPR7550e, and then there is the whole chip shortage... so who knows. Currently, the XPR7550e already has the best portable digital receiver on any radio for <1k, and then some more. I've also found that my problematic areas are not due to lack of reach, is due to abnormally high noise floors, it is hard to do anything when the noise floor at an intersection is -85 dBm...

I love the idea of a larger screen, but then again, since I EDC my radio on my belt, having a giant screen is not a prime need. Now, don't get me wrong, would love to have it, and even more so if you handheld it, but for belt duty with a remote microphone there is no justification to get one just for the larger screen. Also there is the whole battery type and accessory connector port, will it be the same as the current XPR 7550e radios? or will it use a different battery type? What about a different accessory port? Same as the current line?

Last but not least, the cost. I don't expect to find the new radio for <350 bucks on eBay any time soon... so that will put the radio out of my reach for a while.

G.

[tweiss3]

Well, it will do two good things.

1) There may be many more 7550e's on the used market soon

2) Maybe they improved things, like the antenna connector, or added mobile docking for the portables like the APX, I'd dump my current car radio in a second.

[PACNWComms]

If this is the Trbo Ion radio that is being talked about as the replacement for the XPR7550e, it at least appears to be much like the APX Next, and I have been told it also may have the program via network while logged into MOL account. Which means for my current employer, that will not work, and the touchscreen will not function for firefighters. But, I have only put hands on the APX Next, not the XPR Trbo based Ion yet. 

As for the Aeroflex, the one shown was bought when I had my own business, which I may start back up. Bought as part of a group buy.....and my current employer allows me to get software upgrades tacked onto corporate orders. They know I am not in competition with them, and any side work I do only keeps me proficient.

[gman1971]

This is the XPR7550e successor. Its not the ION. Codename is Rajang, but who knows what the final production name will be.

It looks like it uses the same bolt antenna, so that is out of the question. The two remaining questions are the battery compatibility, and the side connector, which sort of looks like it will be compatible, but who knows. They've been using the same microphone connector for APX/XPR radios for the past decade and change, I think replacing it would be a mistake, but that is just me, a nobody.

As for XPR7550e being dumped, I am not so sure. It all depends on how Motorola plays the CPS card. If the radio is like the ION that you require a MOL account along with a network connection to program it from the 'cough' 'cough' "the cloud"... I think it will put off a lot of people. As far as I know there are no plans to discontinue the XPR7550e that I am aware off. I honestly think the XPR7550e is arguable the best blend of usability and performance. 

The ION is a gimmick IMO, its a huge radio, useless with gloves, and the screen can, and will shatter when you might need it the most. Don't get me wrong, its a badass idea, I love the dang thing and I considered getting my hands on mine and ditch the phone... but I just can't get past the fact it can't be programmed from CPS and that it won't take the good old fw2.09 that all my other radios run on. That is not taking into account the cost... of course.

G.

 

G.

[tweiss3]

I signed up for the announcement that comes out in 10 days. Thanks @gman1971

[PACNWComms]

On 1/19/2022 at 1:47 PM, gman1971 said:

the APX900 and the XPR7550e SMA are basically the same radio

Wejoke at work how much the APX900 and XPR7550e are alike. If someone came up with a P25 flash/software load,whatever it gets called, I know a lot of people that would keep/buy/re-use them.

[PACNWComms]

Just now, PACNWComms said:

Wejoke at work how much the APX900 and XPR7550e are alike. If someone came up with a P25 flash/software load,whatever it gets called, I know a lot of people that would keep/buy/re-use them.

APX900 Model 2 on left and XPR7550e on right. (XPR7550e is like Model three, full keypad and display, where a XPR7350e has no display or keypad like a Model 1, there is no Model 2 abbreviated keypad version like the APX series.)

[gman1971]

There is an APX900 with full keypad as well. It is basically the same radio as the Callbox SMA XPR7550e. I haven't looked at the internals, but I suspect they are the same. 

G.