Be forewarned - the following is a very long post with some degree of technical "jargon". If you don't like this type of post then PLEASE go no further!
My initial inclination was not to start a new thread but to include this as a post in the already established thread concerning the introduction of GRE's new PSR800 product. This is because of GRE's very significant (in my opinion) decision to include a true raw discriminator output on that product. For a product primarily targeted towards non-technical "open box turn on and use" type customers this is an interesting "advanced user" feature that tells me that GRE is not wholly abandoning this advanced user customer base as so many seem to fear. I see the following suggestion as a logical and practical "next step". However, because this post would veer significantly off topic for that thread I decided it would be better form for me to start a new one.
I have been thinking long and hard about what GRE could do in terms of developing and bringing to market a future scanner designed for advanced users that still could be cost effective for them to produce and for us to purchase. I personally think that most very advanced technical scanner users would be willing to spend upwards of close to a thousand dollars or more for a well designed advanced scanning product with the right features and performance but I also realize that this cost point probably makes the market analysis folks at GRE very nervous and unlikely to be willing to tackle. Therefor I am going to make a suggestion that should be very feasible in terms of staying near to the already established $500 market bearable price point.
To keep the cost down, this product would target a limited subset of what we, the advanced technically oriented scanner enthusiasts want. It does not directly address, for example, the need for better front end RF performance though that is something I think we strongly desire, because I see so much obvious reluctance to do this on the part of GRE that I must assume they have looked at this and simply decided it was not cost effective enough to achieve. I disagree personally with this decision, if true, but, will concede to it for the purposes of this suggestion.
This suggestion would target the need for accommodating new advanced forms of digital voice modulation used in the narrow band LMR segment that lie outside the already well supported in consumer scanners P25 Phase I mode. This would accommodate both current and future modes that contain their information well below 500KHz in bandwidth. Currently used modes of this ilk would include MotoTurbo/DMR TDMA and NXDN FDMA based variants. The potential to support the current Motorola variant of the future TDMA P25 Phase II standard as well as the eventual standard itself when finalized is also there and simply subject to user supplied software.
That last sentence should clue one in on the fact that this is a suggestion that focuses on usage with an externally connected computer so, right away, one can see that this is not a stand-alone product and not terribly well suited to portable usage. This is true but it also allows for continued stand-alone usage when dealing solely with the currently well understood "normal" digital mode of P25 Phase I. That is, the scanner will retain its stand alone "normal" operational characteristics when not dealing with this "new feature".
I have written many times in these forums about the need for a consumer scanner to include a hardware I/Q demodulator section as well as the common FM discriminator circuit and include well isolated switchable raw unfiltered outputs of each circuit available for post processing using a computer equipped with the necessary A/D converter PCIe add-on card (given the nature of raw I/Q demodulator analog outputs something beyond the common low audio frequency sound card would be needed; however, if an internal A/D converter is used, only the digital bits need be accommodated to convert to USB format, etc.). Unfortunately, it appears to me as though this is another bit of circuitry that falls under the "making the cost analysis folks extremely nervous to the point of becoming violently ill" title. Therefor, once again, I reluctantly concede defeat here and will NOT include this in my current cost-centric suggestion.
To still accommodate the desired need and yet keep the cost and added complexity as low as possible I suggest the simple inclusion of an isolated tap on the final intermediate frequency, aka "IF", output located prior to the final IF filter. On a desktop unit this could simply be another BNC connector located on the back of the unit which could be labeled something like "Final IF Output" or some such. Since the scanner's final IF is the common 455KHz IF (I believe - or around that, at any rate) it should easily accommodate LMR narrow band modes using less than that bandwidth to contain their information and, because of the low frequency, the required additional circuitry and PCB layout which includes a unity gain (or moderate gain, if needed) isolation amplifier and associated transmission line plus connector would not be complex nor would it be terribly difficult to implement in a practical, repeatable and factory produce-able fashion. If inclusion in a portable format is also deemed practical then, for hand held models, the usage of a small coaxial connector similar to what the older hand held cellular phones had to allow connection to an external antenna: I believe it was a small SMB variant usually recessed in the case with a stiff removable rubber cover over it when not in use - something like a larger version of what one sees commonly used for antenna connections on many 802.11 radio cards used in laptops. I would make the rubber cover have a good tab connected to the case of the scanner so as to mitigate potential loss-of-cover issues. Operationally, the external IF output would be controlled from an "Expert Feature" sub-menu using the scanner itself as well as from software such as Don Starr's WINXXX series. Ideally, the isolation amp would be effective enough to allow the scanner to continue to operate normally when activated and, obviously, not load down or otherwise contaminate the final IF chain both before and after the tap point regardless of on/off status. Making the scanner work normally when the tap is engaged would be nice for reasons addressed next.
Since the hardware added to the scanner for this suggestion is minimal and not complex in any way it should add very little to the cost of the scanner and allow it to be used in the same fashion as is done today. No additional complexity is added to the cost sensitive RF and demodulator sections only very little to the final low frequency IF section. A user could simply buy this scanner and use it as done today and potentially never use the IF tap. Remember, this model would still be targeted to the more advanced user rather than the turn-on-and-use out-of-box crowd that is targeted by units such as GRE's PSR800 and Uniden's HP-1 so I would think that the additional cost for the added IF tap (which, I believe, conservatively should not exceed $20 to $50 added to the current purchase price) should not terribly bother the advanced user target customer base. As extra options, GRE could provide connecting cables and - this is significant - a dedicated PCIe computer card which contains a decent A/D converter and associated circuitry for usage with the scanner's final IF. GRE could include basic control software and, maybe, basic demodulating software if practical (possibly "lite" versions of, say, whatever future variant of DSD Linux and/or Windows software is available). If the IF tap can be switched in while maintaining the scanner's normal operational characteristics then the scanner could be software controlled and status monitor-able while allowing the use of the IF tap which gives the user with the necessary computer hardware and software the ability to use the scanner to receive internally supported modes (FM, P25 Phase I) while allowing the connected computer plus decoding software the ability to demodulate other modes (MotoTurbo, NXDN, etc.) when the scanner stops on such a signal. With the proper control, status monitoring, and demodulating software, the operation could be potentially seamless in terms of modulation mode handling regardless of whether the mode is one internally/natively handled by the scanner or is one of the "other" modes such as MotoTurbo or NXDN or, potentially, P25 Phase II. Audio from the scanner could even be routed to the computer's sound card to allow the user to have "it all" come out of the same speaker, if so desired (likewise, the scanner audio could be mixed with the computer audio externally and fed to external speakers). The complexity and potential operational characteristics is/are limited only by the user's additional hardware and software.
This allows GRE many advantages relative to current lines. The cost of the product by itself would only be minimally impacted by the added IF tap and would still give more advanced users seeking a more streamlined approach to non-P25 Phase I demodulation a reason to consider this scanner for purchase. The IF tap yields a far more flexible signal to play with for current and future digital modulation modes than the usual discriminator output. This provides future processing software writers nearly unlimited "room to play" for narrow band LMR digital modes. This is a good low cost alternative to including true I/Q raw analog or digital bits output. The only downside is the requirement of a suitable A/D converter card for the PC over and above the standard audio frequency sound card. Again, however, the advanced user would likely not be daunted by this need and actually welcome the significantly added flexibility this system adds beyond what can be attained using the traditional FM discriminator + sound card solution. The user could elect to purchase the GRE A/D card or a third party product as long as it can process the final IF frequency range thereby allowing the user to choose, for example, higher performance than what the "basic" GRE card offers. This allows a tiered user base approach - starting with the basic scanner as normal today and moving toward whatever maximum complexity is allowed by additional PC hardware and software. Potentially, GRE's card, if offered, could even be marketed toward users of non-GRE models or users of other GRE models without this feature so long as the IF is compatible (455KHz is very common) and a tap for the IF is provided via modification (if not already available). So, although this may be a small market, this might even offer some additional revenue for GRE. The card could be designed and manufactured in house or could be a rebranded model from another supplier - whatever GRE deems most cost effective.
This has been a long post and I apologize for that. Nevertheless, I see this as a very good potential future product or system of products for GRE that would greatly appeal to advanced scanner enthusiasts without adding significant additional cost to the basic product.
-Mike
My initial inclination was not to start a new thread but to include this as a post in the already established thread concerning the introduction of GRE's new PSR800 product. This is because of GRE's very significant (in my opinion) decision to include a true raw discriminator output on that product. For a product primarily targeted towards non-technical "open box turn on and use" type customers this is an interesting "advanced user" feature that tells me that GRE is not wholly abandoning this advanced user customer base as so many seem to fear. I see the following suggestion as a logical and practical "next step". However, because this post would veer significantly off topic for that thread I decided it would be better form for me to start a new one.
I have been thinking long and hard about what GRE could do in terms of developing and bringing to market a future scanner designed for advanced users that still could be cost effective for them to produce and for us to purchase. I personally think that most very advanced technical scanner users would be willing to spend upwards of close to a thousand dollars or more for a well designed advanced scanning product with the right features and performance but I also realize that this cost point probably makes the market analysis folks at GRE very nervous and unlikely to be willing to tackle. Therefor I am going to make a suggestion that should be very feasible in terms of staying near to the already established $500 market bearable price point.
To keep the cost down, this product would target a limited subset of what we, the advanced technically oriented scanner enthusiasts want. It does not directly address, for example, the need for better front end RF performance though that is something I think we strongly desire, because I see so much obvious reluctance to do this on the part of GRE that I must assume they have looked at this and simply decided it was not cost effective enough to achieve. I disagree personally with this decision, if true, but, will concede to it for the purposes of this suggestion.
This suggestion would target the need for accommodating new advanced forms of digital voice modulation used in the narrow band LMR segment that lie outside the already well supported in consumer scanners P25 Phase I mode. This would accommodate both current and future modes that contain their information well below 500KHz in bandwidth. Currently used modes of this ilk would include MotoTurbo/DMR TDMA and NXDN FDMA based variants. The potential to support the current Motorola variant of the future TDMA P25 Phase II standard as well as the eventual standard itself when finalized is also there and simply subject to user supplied software.
That last sentence should clue one in on the fact that this is a suggestion that focuses on usage with an externally connected computer so, right away, one can see that this is not a stand-alone product and not terribly well suited to portable usage. This is true but it also allows for continued stand-alone usage when dealing solely with the currently well understood "normal" digital mode of P25 Phase I. That is, the scanner will retain its stand alone "normal" operational characteristics when not dealing with this "new feature".
I have written many times in these forums about the need for a consumer scanner to include a hardware I/Q demodulator section as well as the common FM discriminator circuit and include well isolated switchable raw unfiltered outputs of each circuit available for post processing using a computer equipped with the necessary A/D converter PCIe add-on card (given the nature of raw I/Q demodulator analog outputs something beyond the common low audio frequency sound card would be needed; however, if an internal A/D converter is used, only the digital bits need be accommodated to convert to USB format, etc.). Unfortunately, it appears to me as though this is another bit of circuitry that falls under the "making the cost analysis folks extremely nervous to the point of becoming violently ill" title. Therefor, once again, I reluctantly concede defeat here and will NOT include this in my current cost-centric suggestion.
To still accommodate the desired need and yet keep the cost and added complexity as low as possible I suggest the simple inclusion of an isolated tap on the final intermediate frequency, aka "IF", output located prior to the final IF filter. On a desktop unit this could simply be another BNC connector located on the back of the unit which could be labeled something like "Final IF Output" or some such. Since the scanner's final IF is the common 455KHz IF (I believe - or around that, at any rate) it should easily accommodate LMR narrow band modes using less than that bandwidth to contain their information and, because of the low frequency, the required additional circuitry and PCB layout which includes a unity gain (or moderate gain, if needed) isolation amplifier and associated transmission line plus connector would not be complex nor would it be terribly difficult to implement in a practical, repeatable and factory produce-able fashion. If inclusion in a portable format is also deemed practical then, for hand held models, the usage of a small coaxial connector similar to what the older hand held cellular phones had to allow connection to an external antenna: I believe it was a small SMB variant usually recessed in the case with a stiff removable rubber cover over it when not in use - something like a larger version of what one sees commonly used for antenna connections on many 802.11 radio cards used in laptops. I would make the rubber cover have a good tab connected to the case of the scanner so as to mitigate potential loss-of-cover issues. Operationally, the external IF output would be controlled from an "Expert Feature" sub-menu using the scanner itself as well as from software such as Don Starr's WINXXX series. Ideally, the isolation amp would be effective enough to allow the scanner to continue to operate normally when activated and, obviously, not load down or otherwise contaminate the final IF chain both before and after the tap point regardless of on/off status. Making the scanner work normally when the tap is engaged would be nice for reasons addressed next.
Since the hardware added to the scanner for this suggestion is minimal and not complex in any way it should add very little to the cost of the scanner and allow it to be used in the same fashion as is done today. No additional complexity is added to the cost sensitive RF and demodulator sections only very little to the final low frequency IF section. A user could simply buy this scanner and use it as done today and potentially never use the IF tap. Remember, this model would still be targeted to the more advanced user rather than the turn-on-and-use out-of-box crowd that is targeted by units such as GRE's PSR800 and Uniden's HP-1 so I would think that the additional cost for the added IF tap (which, I believe, conservatively should not exceed $20 to $50 added to the current purchase price) should not terribly bother the advanced user target customer base. As extra options, GRE could provide connecting cables and - this is significant - a dedicated PCIe computer card which contains a decent A/D converter and associated circuitry for usage with the scanner's final IF. GRE could include basic control software and, maybe, basic demodulating software if practical (possibly "lite" versions of, say, whatever future variant of DSD Linux and/or Windows software is available). If the IF tap can be switched in while maintaining the scanner's normal operational characteristics then the scanner could be software controlled and status monitor-able while allowing the use of the IF tap which gives the user with the necessary computer hardware and software the ability to use the scanner to receive internally supported modes (FM, P25 Phase I) while allowing the connected computer plus decoding software the ability to demodulate other modes (MotoTurbo, NXDN, etc.) when the scanner stops on such a signal. With the proper control, status monitoring, and demodulating software, the operation could be potentially seamless in terms of modulation mode handling regardless of whether the mode is one internally/natively handled by the scanner or is one of the "other" modes such as MotoTurbo or NXDN or, potentially, P25 Phase II. Audio from the scanner could even be routed to the computer's sound card to allow the user to have "it all" come out of the same speaker, if so desired (likewise, the scanner audio could be mixed with the computer audio externally and fed to external speakers). The complexity and potential operational characteristics is/are limited only by the user's additional hardware and software.
This allows GRE many advantages relative to current lines. The cost of the product by itself would only be minimally impacted by the added IF tap and would still give more advanced users seeking a more streamlined approach to non-P25 Phase I demodulation a reason to consider this scanner for purchase. The IF tap yields a far more flexible signal to play with for current and future digital modulation modes than the usual discriminator output. This provides future processing software writers nearly unlimited "room to play" for narrow band LMR digital modes. This is a good low cost alternative to including true I/Q raw analog or digital bits output. The only downside is the requirement of a suitable A/D converter card for the PC over and above the standard audio frequency sound card. Again, however, the advanced user would likely not be daunted by this need and actually welcome the significantly added flexibility this system adds beyond what can be attained using the traditional FM discriminator + sound card solution. The user could elect to purchase the GRE A/D card or a third party product as long as it can process the final IF frequency range thereby allowing the user to choose, for example, higher performance than what the "basic" GRE card offers. This allows a tiered user base approach - starting with the basic scanner as normal today and moving toward whatever maximum complexity is allowed by additional PC hardware and software. Potentially, GRE's card, if offered, could even be marketed toward users of non-GRE models or users of other GRE models without this feature so long as the IF is compatible (455KHz is very common) and a tap for the IF is provided via modification (if not already available). So, although this may be a small market, this might even offer some additional revenue for GRE. The card could be designed and manufactured in house or could be a rebranded model from another supplier - whatever GRE deems most cost effective.
This has been a long post and I apologize for that. Nevertheless, I see this as a very good potential future product or system of products for GRE that would greatly appeal to advanced scanner enthusiasts without adding significant additional cost to the basic product.
-Mike
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