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Re: RA8875 display problems with T4.x - a visual study
Very interesting... Jack, W8TEE
By jjpurdum · #33239 ·
Re: RA8875 display problems with T4.x - a visual study
Hi Mark- The T41 project has been successful with this device: https://www.digikey.com/en/products/detail/toshiba-semiconductor-and-storage/74HC125D/6198923 There was a run of a couple hundred kits
By Greg KF5N · #33238 ·
Re: RA8875 display problems with T4.x - a visual study
Just curious; do you think a piece of UTP CAT 5 or 6 would work? John, W5JSS <tmrob4@...> wrote:
By John Schindler · #33237 ·
Re: Ver066_9_3_22_25
Oh, build results: Memory Usage on Teensy 4.1: FLASH: code:305956, data:129336, headers:9116 ? free for files:7682056 RAM1: variables:191584, code:283272, padding:11640 ? free for local
By epif18@... · #33236 ·
Ver066_9_3_22_25
Hey yall', I was running Ver66.9 and it seemed to address some of the issues I was having.? Calibrated FREQ and REC I/Q.? All good through several shutdowns and startups. Shut my radio down and
By epif18@... · #33235 ·
Re: RA8875 display problems with T4.x - a visual study
In the T41, there is also crosstalk on the display cable.? In the image below, the shorter ribbon cable does not work.? You need a cable of this type with about half this length to work.? The
By Terrance Robertson, KN6ZDE · #33234 ·
Re: RA8875 display problems with T4.x - a visual study
So we designed those resistors into the V12.6 main board after reading the same posts you read¡­ and that is what everyone has today (see the main board schematic out on my github). After a lot pf
By K9HZ · #33233 ·
RA8875 display problems with T4.x - a visual study
The subject of problems with the SPI interface between the T4.x & RA8875 displays comes up quite often on the Teensy forum.? I would like to point out that the SPI interface is not anything that PJRC
By Mark J Culross · #33232 ·
Re: Oscillations on high bands
In ver 50.0 in SSB and CW modes, TX_BPF_SEL and TR_BPF_SEL both switch states when PTT or Key engaged In ver 66.4 in CW mode, TX_BPF_SEL and TR_BPF_SEL both switch states when Key engaged. In SSB
By D Solt · #33231 ·
Re: I/O Weirdness
Might consult Al. He may have stuck some code back in to work with the legacy V11 LPF. I recall there was some discussion of that several months ago. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ
By K9HZ · #33230 ·
Re: boards and kits and stuff
SPI on the Teensy today is in fractions of the (600 MHz) clock speed and that can be very high (eg 50 MHZ). There is a way to set it in software but i have not experimented with it. That certainly has
By K9HZ · #33229 ·
Re: Oscillations on high bands
SWAG is a technical term:? "Scientific Wild Ass Guess". -- 73 Greg KF5N
By Greg KF5N · #33228 ·
Re: Oscillations on high bands
What is a SWAG? [email protected]> wrote:
By D Solt · #33227 ·
Re: Oscillations on high bands
Bill, what I was trying to get at was the *measurements* of the signal path.? The behavior versus frequency. -- 73 Greg KF5N
By Greg KF5N · #33226 ·
Re: Oscillations on high bands
Since its a SWAG¡­ explain why it happens with V69 of the software but not with V50. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch ¨C
By K9HZ · #33225 ·
Re: Oscillations on high bands
So that would be a reason for the isolation to degrade versus increasing frequency. Because the module has common ground inductances on the input and output. Just a SWAG here, it's hard to tell
By Greg KF5N · #33224 ·
Re: Oscillations on high bands
Yes
By D Solt · #33223 ·
Re: Oscillations on high bands
This switch is a plug-in module? -- 73 Greg KF5N
By Greg KF5N · #33222 ·
Re: Oscillations on high bands
It is here: https://github.com/DRWJSCHMIDT/K9HZ/blob/main/K9HZ_LPF_Module/K9HZ_LPF_V1.00_Schematic_PDFs/K9HZ_LPF-Carrier_Relay_Board_Schematic_V1.00_07-25-24_KiCad.pdf
By Oliver KI3P · #33221 ·
Re: Oscillations on high bands
Hi Oliver, where is the schematic of the TR switch? I would like to see the circuit topology.? A few decades ago(!) I was designing TR switches and I'm curious about this one. -- 73 Greg KF5N
By Greg KF5N · #33220 ·