Re: boards and kits and stuff
¿ªÔÆÌåÓý¡°No one complained about display issues that I can recall.¡±? You might review the posts from fall two years ago to refresh your memory when Al with a group of others was working on ways to calm the noise down. ? That the bus driver part that was used desensitized the RX by 17 dB (measured in my lab).? The display made that worse as a noisy antenna.? Your experience may be different. ? The V12.6 MAIN board, being a 4-layer board, designed/ tested using software with techniques to minimize noise and impedance mismatch. ? I¡¯m pretty much done with the Teensy¡ because the SPI interface is pathetic and inferior to other choices like HDMI¡ and so are many (not all) of the SPI buss displays I¡¯ve tried. ??I hope to work with Oliver to compartmentalize the T41 code¡ for a RPi as a first step, and then eventually to a combo RPi and FPGA.?? I¡¯ve made great strides understanding how to move, decouple, and enhance the T41 recently¡ into those devices and it will start once the 100W PA and ATU is shipping.? Again there is no public offering here but I¡¯m willing to work with anyone with similar motives. ? Of course it¡¯s nonsense to speak authoritatively this early on stuff I don¡¯t own and have direct experience with yet so I don¡¯t know if this will lead to a better situation or just ?different problems rearranged. ? Freight company delivered a 4-axis CNC machine here yesterday. ?Makera.? ?Prototyping is taking a major step forward.? Yet another thing to learn. ? ? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? From: [email protected] <[email protected]> On Behalf Of Greg KF5N via groups.io
Sent: Thursday, March 20, 2025 9:57 AM To: [email protected] Subject: Re: [SoftwareControlledHamRadio] boards and kits and stuff ? Hi Terrance- ? The original V11 Main board design uses a driver IC for the SPI bus which drives the display.? Same for the original kits.? No one complained about display issues that I can recall. There was some moderate noise from the display which is for the most part, overridden by atmospheric noise when you connect an antenna.? Some of that noise was due to inadequate bypassing on the QSD board. I have designed a new Main board, with an improved layout and more bypassing/decoupling.? It uses the same SPI driver as the original.? Also I have a new QSD2 which has improved bypassing/decoupling. The display performance is solid and any display related noise is inconsequential. It's a good assumption that if the original display driver had been incorporated into the V12 Main board, no one would be complaining about bad display behavior or display related noise (V12 has EMI improvements). ? The next step is to investigate boosting the Teensy's GPIO drive strength and bandwidth via software changes.? If that is successful, the driver IC (and buffer board) could possibly be eliminated without anyone complaining about bad display behavior, and with V12s EMI improvements, display noise would probably be a non-issue as well. ? -- 73 Greg KF5N |
K9HZ