P25RX P25 Phase 1 Receiver With Bluetooth Audio Support

btt

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Mar 11, 2020
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AB5ID,

Thank you for the reply. Yes, I think you could put something together with a Raspberry Pi / Higher-end RTL receiver / and OP25. Based on my experience with the RTL, I don't think you would be able to achieve the same level of RF performance. I have not had a chance to test the RTL / OP25 combination in a simulcast environment. Does it perform well? Does anyone offer a complete system around the price you are looking for?

The pricing for the P25RX is currently based on low-volume cost, so I may be able to something on pricing. $150 will not be possible for me.
 

buddrousa

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And why would I want to spend $300 for a P25 Phase 1 only receiver when I can get several different options that enclude DMR P25 Phase 1 and Phase 2 scanner for the same money?
 

btt

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The current pricing is $292. It is true that it currently supports P25 Phase 1 only. DMR and Phase 2 are possibilities for the future firmware developments. Currently, Phase 2 is not operating in my receiving area. If someone can provide some good samples, I could start working on that if there is enough interest in this product.

I have had some success with DMR / Conn+. Still some minor issue with getting the wrong go-to-channel sometimes and some issues with determining correct slot to decode (get voice from both slots sometimes). I haven't touched DMR for some months. Been too busy polishing the configuration software / writing user manual / getting ready for release of the P25RX.

@buddrousa, to answer your question, Here are some features that might be appealing to some:

-Excellent performance with Simulcast system.

-Bluetooth audio streaming. Very nice for mobile operation. Plug it in, pair it with your bluetooth stereo / speaker system the first time, and go. The Bluetooth feature is also handy for a fixed location situation where you want to get the receiver / antenna up higher (on a bookshelf for example) and be able to just turn on a Bluetooth speaker when you want to listen. This is nice for people who just want to listen, but can't get around too good.

-Open-source configuration software with integrated frequency database / test functions that will run on Windows 7, 10, Linux, (possibly Mac)
-Small, rugged, portable, stand-alone aluminum enclosure with USB-C power connector.
-You would be supporting a developer from the USA who needs to start making an income again in order to pay the bills.

As I said before, I could probably lower the price a bit if there is enough interest (volume pricing).
 

buddrousa

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Good luck I just do not see it for me. Where has it tested in a true Simulcast environment and what was it tested against?
 

btt

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"Where has it tested in a true Simulcast environment and what was it tested against?"

It was developed around the Tri-cities, Wa area. See here: Benton County 800 Trunking System, Benton County, Washington - Scanner Frequencies
From RR description: "Two additional sites were added to the network, to help boost handheld coverage in fringe areas that the old radio system had coverage problems in; thus, making it a nine-site simulcast system, using linear phase modulation (CQPSK)."

During development, simulcast issues were resolved by getting testers in the 3 worst locations I could find (due to simulcast) in Pasco, Richland, and Kennewick. All of these locations were being hit by multiple towers. In the beginning, it was definitely a problem for those 3 testers. Many voice segments frames being dropped at all 3 locations. After improvements to the quadrature decoder, filters, and the multi-rate, poly-phase symbol synchronizer, all three testers ended up with excellent out-of-box performance at these locations.
 

btt

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Mar 11, 2020
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Thanks again for the replies. Pricing has been adjusted. I hope this will generate some interest.

Here is a video demonstrating initial configuration of a control channel using the integrated frequency database.
 
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