The official "I want LSM to work properly in my scanner" thread

[kayn1n32008]

Also comparing two entirely different products.

Yes. I fully agree. They are two different products.

The Unication devices were designed as pagers,

But more importantly, they were designed to properly decode (W)CQPSK wave form.

Even knowing that most simulcast P25 Systems use something other than C4FM, Uniden and Whistler still chose to use a discriminator tap.

They are knowingly selling garbage receivers that can not be fixed with firmware.

not scanners which is also why they are band specific. They also have their own range of problems when dealing with large systems but that’s another story.


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Fully agree. Band specific is not a bad thing, unless you have simulcast Systems in more than one band, or you need to scan more than one band to cover everything you like to listen to.



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[mule1075]

Well I fixed this problem permanently with an XTS 5000. Everyone should get one.

Not everyone is as lucky or have the ability or resources you do.

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[dakota91]

Issue with XTS5000

The problem most people will have with using an XTS 3000 or 5000 Motorola radio is that the average user doesn't have the cable, software, or knowledge to program them. I've looked at an XTS 3000 on ebay and the seller offered to program it, but only in conventional mode rather than trunked. On a large trunked system, programmed as conventional would go no-stop and you would be unable to monitor what you really want. I also believe a 5000 would require the radio to affiliate with the site to operate properly. The problem with these radios is that they weren't built to just monitor a system, but rather to interact with it.

 

[Project25_MASTR]

The problem most people will have with using an XTS 3000 or 5000 Motorola radio is that the average user doesn't have the cable, software, or knowledge to program them. I've looked at an XTS 3000 on ebay and the seller offered to program it, but only in conventional mode rather than trunked. On a large trunked system, programmed as conventional would go no-stop and you would be unable to monitor what you really want. I also believe a 5000 would require the radio to affiliate with the site to operate properly. The problem with these radios is that they weren't built to just monitor a system, but rather to interact with it.

3000’s are problematic in that there is a very narrow firmware window which is 9600 bps capable (and they are more hassle to flash than a 2500/5000).

1500/2500/5000’s can perform a non-affiliate scan but it requires a system key to do right (which a 3000 does as well).


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[APX8000]

The problem most people will have with using an XTS 3000 or 5000 Motorola radio is that the average user doesn't have the cable, software, or knowledge to program them. I've looked at an XTS 3000 on ebay and the seller offered to program it, but only in conventional mode rather than trunked. On a large trunked system, programmed as conventional would go no-stop and you would be unable to monitor what you really want. I also believe a 5000 would require the radio to affiliate with the site to operate properly. The problem with these radios is that they weren't built to just monitor a system, but rather to interact with it.

That’s completely incorrect. First of all, you can very easily create a Motorola account and download software and firmware, buy cables, etc. of course, you have to pay for it. Second, you can program an XTL/XTS to monitor a trunked system. You do not have to affiliate to the system in order to pass the audio. If you program an XTS correctly, you would never accidentally affiliate as all the channels in your 16 selector are conventional channels that call up trunked scanlists. Those trunked channels are “hidden” in channels 17 and higher. You do need a system key generator and that is NOT available through Motorola but readily available using other means. Third, knowledge is something that is learned from reading, asking questions and experience. I don’t spoon feed people and i find the best part of this hobby is learning things.

Now the BUT....if you don’t know what you are doing you CAN not only get your radio bricked and cause safety issues for legit public safety subscribers on the system.

I don’t recommend scanners anymore until they fix LSM issues. Most systems are moving in that direction and why pay for something you can’t use half the time. I do however like the Unication pagers G4 and G5 and the reception range is equal to my commercial portables for the most part.


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[scanmanmi]

They are knowingly selling garbage receivers that can not be fixed with firmware.

So for us technically challenged people what is the fix? Will someone come out with an announcement that they are using CQPSK? Why haven't they done it yet? I am waiting to buy a scanner until they fix this.

 

[kayn1n32008]

So for us technically challenged people what is the fix? Will someone come out with an announcement that they are using CQPSK? Why haven't they done it yet? I am waiting to buy a scanner until they fix this.

The fix is a receiver that is designed to deal with W/CQPSK waveform.

The when and why I can not answer. Ask Uniden and Whistler.


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[KA1RBI]

This is from a while back, just came across it

Over on YouTube user Rob Fissel has uploaded a video showing a comparison between an RTL-SDR using the OP25 decoder and a Uniden BCD996T. Both radios are used to decode a weak P25 Phase 1 LSM signal. He uses a Scantenna antenna with an antenna splitter to run both radios at the same time. His results show that even though the constellation is poor, OP25 does a good job at decoding the signal and producing voice, whereas the BCD996T doesn’t even manage to hear the control channel.

Full article URL: https://www.rtl-sdr.com/p25-decoding-op25-rtl-sdr-vs-a-uniden-bcd996t/

It's understood that Linux and OP25 aren't for everyone, but it's hard to argue with the cost- $30 for a Raspberry PI and $20 for an rtl-sdr and you could (potentially) put together a lot of these for the cost of one scanner....

73

Max

 

[KA1RBI]

and just to followup on this, there is a comment on the rtl-sdr page linked in the previous post:

The BCD996T was first produced in 2006. The op25 project did not get off the ground until 2007 (and did not do trunking at that time). A more relevant comparison would be Uniden’s BCD996P2.

I agree with almost all of this. The only part I'd change would be I'd like to see a comparison of OP25 versus the BCDx36HP series. I'm personally not going to be shelling out $500+ for the "privilege", though...

Max

 

[scanmanmi]

Ask Uniden and Whistler.

I got my answer

JAN 10, 2018 | 09:23AM CST
Caleb replied:

Good Morning,

Unfortunately, we do not have any information for any new or existing scanners that will be updated for CQPSK. We apologize for any inconvenience this may cause.
Thank you for Choosing Uniden!
Caleb
Uniden Tech Supervisor

 

[KR7CQ]

For the average person not able or willing to buy / program a Motorola commercial radio, wanting to monitor LSM systems, and willing to spend about what a BCD536HP costs...there appears to be only one sensible answer...the Unication G4 / G5. Unication has absolutely conquered LSM reception issues. The only challenge, and it's not that big of a challenge, is to structure your programming to effectively use your G4/5 for scanning purposes. I'm in week one and thanks to those on RR willing to help with several questions, I am quite happy with my G4 and cut-outs are a thing of the past. Keep in mind that I am using this device in a big city with multiple systems and more than a half dozen different simulcasts as well as other P25 systems, and I can still listen to what I want to hear through a little creative programming.

Reading that response from Uniden tells me that they really don't "get it" at all. They should darn well be telling people "we are aware of the issues, and are working on it right now for our next model". If Unication can figure it out, they should be able to as well. Uniden and Whistler had better hope and pray that Unication doesn't come out with a true scanner one of these days, because plenty of frustrated scanner users are already buying the G4/5, and with the deal they have now (Phase 2 included for the same price as what Phase 1 devices were at), even more are jumping ship.

 

[APX8000]

Excellent post. They just don’t get it.


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[milcom_chaser]

Yes. I fully agree. They are two different products.



But more importantly, they were designed to properly decode (W)CQPSK wave form.

Even knowing that most simulcast P25 Systems use something other than C4FM, Uniden and Whistler still chose to use a discriminator tap.

They are knowingly selling garbage receivers that can not be fixed with firmware.




Fully agree. Band specific is not a bad thing, unless you have simulcast Systems in more than one band, or you need to scan more than one band to cover everything you like to listen to.



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"Uniden and Whistler still chose to use a discriminator tap."
Um, they use a discriminator tap to decode everything else the RF front-end picks up...

 

[milcom_chaser]

Excellent post. They just don’t get it.


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Maybe, for reason's of staying competitive, they aren't really saying anything, until a new product is announced...

 

[kayn1n32008]

"Uniden and Whistler still chose to use a discriminator tap."

Um, they use a discriminator tap to decode everything else the RF front-end picks up...

And? Why is a discriminator tap an issue when you want to decode a CQPSK wave form?

 

[KA1RBI]

And? Why is a discriminator tap an issue when you want to decode a CQPSK wave form?

So-called CQPSK signals aren't compatible with the FM discriminator method of reception.

Shockingly, CQPSK must be demodulated *as PSK*, not as C4FM/FSK. The PSK method of reception could easily be done if the scanners utilized IF-DSP, a technology which has been in use for many years (see for example the Kenwood TS-590). To do so properly would require a hardware re-design. In the case where such a signal has been corrupted by improperly attempting to decode it using FM methods, no amount of firmware cleverness after the fact can correct it.....

LSM fails two key tests for deciding whether such a signal can properly be called FM (first, it can't be transmitted using a class-C amp in the final; and second, it can't be received properly when using an FM style demod such as a PLL or limiter/discriminator)...

Ask the scanner manufacturers why they don't have IF-DSP. If they did I'd imagine the hardware costs could even be REDUCED (!) compared to today's models. This is because ALL of the final IF hardware circuits would disappear into software: the "FM subsystem IC", the 455 KHz ceramic filters, and all the rest...

73

Max

 

[kayn1n32008]

So-called CQPSK signals aren't compatible with the FM discriminator method of reception.



Shockingly, CQPSK must be demodulated *as PSK*, not as C4FM/FSK. The PSK method of reception could easily be done if the scanners utilized IF-DSP, a technology which has been in use for many years (see for example the Kenwood TS-590). To do so properly would require a hardware re-design. In the case where such a signal has been corrupted by improperly attempting to decode it using FM methods, no amount of firmware cleverness after the fact can correct it.....



LSM fails two key tests for deciding whether such a signal can properly be called FM (first, it can't be transmitted using a class-C amp in the final; and second, it can't be received properly when using an FM style demod such as a PLL or limiter/discriminator)...



Ask the scanner manufacturers why they don't have IF-DSP. If they did I'd imagine the hardware costs could even be REDUCED (!) compared to today's models. This is because ALL of the final IF hardware circuits would disappear into software: the "FM subsystem IC", the 455 KHz ceramic filters, and all the rest...



73



Max

Thank you for that. Not sure why Milcom what ever does not understand that. Heck I'm not even sure why he quoted my post in the first place.

 

[radio3353]

So-called CQPSK signals aren't compatible with the FM discriminator method of reception.

Shockingly, CQPSK must be demodulated *as PSK*, not as C4FM/FSK. The PSK method of reception could easily be done if the scanners utilized IF-DSP, a technology which has been in use for many years (see for example the Kenwood TS-590). To do so properly would require a hardware re-design. In the case where such a signal has been corrupted by improperly attempting to decode it using FM methods, no amount of firmware cleverness after the fact can correct it.....

LSM fails two key tests for deciding whether such a signal can properly be called FM (first, it can't be transmitted using a class-C amp in the final; and second, it can't be received properly when using an FM style demod such as a PLL or limiter/discriminator)...

Ask the scanner manufacturers why they don't have IF-DSP. If they did I'd imagine the hardware costs could even be REDUCED (!) compared to today's models. This is because ALL of the final IF hardware circuits would disappear into software: the "FM subsystem IC", the 455 KHz ceramic filters, and all the rest...

73

Max

Very good post. Thanks for that.

Maybe now the people who come on here and say how difficult it is for Uniden and Whistler to solve the LSM problem or how expensive it will be will now be enlightened as to how false those excuses are. Unication, Motorola, etc have no trouble decoding LSM transmissions. And before the uneducated say "yeah, but, look how much they cost", remember that they are ruggedized products made to work in difficult environments -fires, being dropped, extreme weather, etc. Consumer versions need none of that and would be much less expensive. As I keep saying...it isn't rocket science if you take the time to learn the facts.

 

[APX8000]

The single band Unication G5 pre-order with Phase II included is high $500’s. The dual-band G5 is low $600’s. This is comparable to both Uniden and Whistler products. Difference is....you will actually be able to monitor LSM and the reception range blows the other two out of the water on 7/800 systems with its little factory antenna.

I was at a friends house that has a pretty elaborate shack. With his roof mounted antennas and scanners, I was locking on P25 trunked systems further than he was with my G5 on his desk. He wasen’t even getting the control channel.


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[iMONITOR]

I've been told here in Michigan, our Motorola P25 Simulcast system uses CQPSK (NFM) modulation. Might that explain why I'm not experiencing any problems or frustrations monitoring them using Uniden's BCD996XT, and BCD996P2 scanners. Whistler and most Radio Shack (aka GRE) scanners have worked well for me as well. Macomb County's simulcast system consist of 9 towers, and soon to be more.