MicroP25RX
- Thread starter btt
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I'm currently re-working the Wio Terminal code. The code should end up being much more flexible and easier to modify. It will be open sourced. The new device looks pretty good. I realize it has a hobbyist look to it now with all of the thru-hole technology. The reason for this is because the digital board is an off-the-shelf Cortex-M7 dev board that is still available here in the US (manufactured in Oregon). There are no other viable MCU parts available. It is a good design and the price is right. At some point, I may take a shot at designing a plastic enclosure now that 3D printing is so inexpensive. My 3D modeling skills aren't great. If any of you are good with 3D modeling and have interest in designing an enclosure with an exported STL or STEP file format, let me know.
My son is quite good at this... he designed and 3D printed a ball-bearing, double-gimbaled drink holder for one of his crutches when he had foot surgery a couple years ago. Hard to carry your beer while walking on crutches! I'll forward this thread to him and ask if he's interested in doing an enclosure.
Sounds good. Show him this post and let him know I have the model shown in that rotation. That could be used to assist designing the enclosure.
MicroP25RX
If you wanted to email me those parts I'd be happy to buy my limited quantity worth and send them your way at cost. I'm certain others feel the same way. Can't bankrupt myself but I can see about being an intermediary source as well.
FreqNout
Member
I measure 2.87 x 4.36 x 1.23.
2.87 (Wio width) x 4.36 (bottom of adapter pcb to top of Wio enclosure) x 1.23 (front of Wio to back of Adapter pcb).
n0esc
Feed Provider
@FreqNout Here are a couple that look close depending on how much wiggle room there is and how daring with a Dremel someone would want to be. Also looks like you could get a fair bit of room if the Wio could be gutted from its case and still be useable. https://forum.seeedstudio.com/t/opening-the-case-to-access-to-swd-pads/252248/6
https://www.trustedparts.com/en/part/hammond/1553BTBUBK Would almost be ideal but it's too tight for sure with the Wio enclosed as well. Would require surgery for sure.
https://www.trustedparts.com/en/part/hammond/1455K1202 Aluminum case would need a window cut for the display, and would be a bit of a chunky boy but looks like could also be workable
https://www.trustedparts.com/en/part/hammond/1553BTBUBK Would almost be ideal but it's too tight for sure with the Wio enclosed as well. Would require surgery for sure.
https://www.trustedparts.com/en/part/hammond/1455K1202 Aluminum case would need a window cut for the display, and would be a bit of a chunky boy but looks like could also be workable
Just realized I gave you the wrong measurement for depth. I had the Wio Battery on there when I measured. It should be
2.87 x 4.36 x 0.71"
FreqNout
Member
@n0esc Thanks. This site has some nice options for the diy builder as well
www.boxenclosures.com
Box Enclosures: Custom Plastic Electronic Enclosures
Box Enclosures plastic electronic enclosures in the USA. Custom Enclosures for different applications - handhelds, desktop, wall mounts and more.
www.boxenclosures.com
2.87 (Wio width) x 4.36 (bottom of adapter pcb to top of Wio enclosure) x 0.71 (front of Wio to back of Adapter pcb). Take a look at the model posted earlier here: MicroP25RX_visual2.mkv for reference.
I have a question for P25 system guys. What is the best way to identify an entire "system" uniquely? I thought it would be WACN-SYS_ID, but it appears that there are state-wide systems that have multiple SYS_IDs. Is the system name really the only global, unique identifier? What I'm looking for is a single directory name to store system information in. WACN-SYS_ID would be nice since it doesn't require user input, but appears it isn't globally unique for some systems.
freqseeker
Member
Looks awesome! Looking forward to its release. Thanks for the teaser.
Thanks. Hopefully the new display will put all the misinformation regarding simulcast / LSM to rest. Now you can see the difference in real-time. In reality, there are only two modulations involved with P25 downlinks. FM (4-FSK) and Pi/4 DQPSK (aka LSM). As you can see from the video, the LSM modulation is preferable. The amplitude peaks exactly at symbol time. This gives very precise phase at symbol time. This results in very low EVM symbol decodes. Simulcast is desirable. If your receiver doesn't demodulate/decode it well, don't blame the modulation!
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The WACN+SYS_ID would be the best way to uniquely identify a system. If the same "system" has more than one WACN+SYS_ID it would be connected via an Inter Subsystem Interface (ISSI) and technically would be two different "systems" connected together.
I'm not aware of any "systems" that have different WACN+SYS_IDs but I do know of many different "systems" that are connected via ISSI for interoperability reasons.
Edit: I should clarify, I have seen 'statewide' "systems" with some 'sites' that have different WACN+SYS_IDs but those are usually 'systems' that started out independently and were later joined together and instead of reprogramming all the radios for the new WACN+SYS_ID they just networked the 'sites' together via ISSI.
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Thank you for the reply. I believe you are correct about WACN+SYS_ID being the best solution. Here is an example of sate-wide system with multiple sys_ids: Washington Department of Transportation (P25) Trunking System, Various, Multi-State For talk groups, I will make a provision to link a single talk group file to multiple WACN+SYS_ID systems.
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So this is a non-Motorola (Harris??) system and they do seem to use the SYS_ID instead of the FRSS for different "zones" within the same WACN, I'm not sure why they do this, maybe they just want to be different? I'm not that versed in non-Motorola systems but I think they would need to use an ISSI to link between the different SYS_IDs in the "system" but I'm not sure about that. If so, doing this would theoretically limit them on the number of talk groups that would be able to talk between SYS_IDs. To be honest I kind of forgot that they did this, definitely puts a bit of a bugger in trying to organize things.
I forgot to mention a couple of things about the IQ FFT in the video. That is log10 scale, 1024 bins, Blackman window. The FFT is of the analog-filtered signal being fed to the ADC input after it has been digitally filtered. The "IQ plot" is the time-domain view of the same signal. What is shown is the result of the AGC working to maintain a target signal level to the ADC. The insanely good rejection on either side of the channel is due to the analog, 9-element IF / channel filter and the linear phase FIR filters. The more important plots are the symbol plot and QPSK constellation. They give you a very direct view as to how well the receiver is able to demodulate / decode the signal.
