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A buddy reported to me that my zBitx was showing 1.8s of DT in his WSJT-X console, and I can verify same with my own copy locally. I have verified that the clock on the zBitx is to the instant correct with WWV, ie. when I hear start of the tone at the top of the minute, the minute switches over on my zBitx, as well as with my NTP synchronized devices around the shack. Yet, when I answer a call or start a CQ, I'm showing as 1.8 seconds out of sync with most other people. Also what 'app' or library or whatever is being used for FT8? 73, .Vince

I have tried different power supplies, all capable of more than 3 amp. Same results. Tried reducing Drive down to 65, that appears to work, but at 70 it resets the Pi consistently. It does it very quickly, so not temperature related. Any suggestions? Software updated as of April 29th 2025

NOTE – This is focused on zBITX CW using a Straight Key. Scenario Straight Key CW is not really possible unless you send at 20+ WPM. Even then is troublesome, causing sending errors. Background - zBITX runs sBitx in a full RasPi OS install – it is not a stripped down version - A sBitx GUI is always running on the RasPi Desktop - zBITX adds and manages a second GUI running on a Touch Screen LCD - Two GUIs with dynamic Spectrum and Waterfall features require processing time - The sBitx CW is Semi Break-in, not Full Break-In - A Key-Down GPIO Input being detected switches the sBitx to Transmit Mode - No Key Down for ‘x milliseconds’ switches the sBitx back in to Receive Mode - The Back-To-Receive Mode delay time is currently settable from 0-1000 milliseconds - The Key-Down GPIO Input does not come from a GPIO IRQ (Interrupt) – it is polled. - The frequency of polling for a Key-Down GPIO Input is inconsistent. - The frequency of polling is theoretically every millisecond. But that does not happen. Concept Once in Transmit Mode, all else (except audio which runs in a separate thread), needs to be inhibited in order to allow the device to just manage CW sending . Problem Detail A GLib g_timeout_add() is used to call a ui_tick() function in sbitx_gtk,c every one millisecond (1ms). Polling for a Key-Down GPIO Input is done in this ui_tick() function. The ui_tick() function is very busy as it does a lot of other things, some of which look like they require a lot of time to process. So, it may take much more than 1ms for ui_tick() to complete. If a GLib timeout function is called again before its previous execution has completed, it does not cause any errors or unexpected behavior. The function is simply re-scheduled for the next timeout interval. This will behavior will delay the Polling for a Key-Down GPIO Input. Solution The ui_tick() function was revised to (1) Move the polling for a Key-Down GPIO Input to the top of the function, and (2) after having done that Key-Down GPIO polling, do a Return to get out of that function if we are in Transmit Mode. Result This change allows Straight Key use at very slow speeds. This change also helps with slow speed paddle keying. (however, it is just like the days of old, with nothing to look at while you are sending) This change proved my concept. BUT there are still some glitches, which are probably caused by ui_tick() getting past my “are we in transmit mode?” test and proceeding to get caught up in handling all of the other time consuming processing that takes place in the ui_tick() function. So it can be not looking whenever a Key Down occurs. So, it is not the complete answer. A copy of my revised sbitx_gtk,c is attached. Search on k3jzd to find my changes. Next Steps - Look at extending the Semi Break-In Hang Time (called “delay” in zBITX). The current limit of 1000ms (1 second) is often not enough - we pause to think a little from time to time. I’m still looking for where this 1000ms limit has been established so that I can change it to 5000 which will let the user set it to suit his style. - Look at using GPIO Pin IRQs (interrupts). I need to sort out how this works with a GPIO Input for DASH, but none that I have found for DOT. 72, Jody – K3JZD

Is there any estimate on when the sBitx v4 and the zBitx will be available for purchase?

Hi Is it possible to use the zbitx as if it was a Hermes Lite 2 (HL2)? I've searched and maybe It can, and maybe my search terms not correct as I'm a new HAM. Thanks

Hi, I have uploaded a file to a new folder called "Zbitx tests" in the Zbitx files section. This file is of some tests of TX Intermodulation. Kevin

Dear all, I have a Sennheiser USB Audio Headset Epos C20 and would like to use it with the zBitx. It has a USB Bluetooth Dongle but not sure if it works out of the box with zBitx. I came across this software: https://github.com/drexjj/sBITX-toolbox Has anybody installed and tested this add on software on the zBitx? It offers USB Audio Support (and more) … thats why I am curious ? 73 Peter

Got my zBitx two weeks ago and the CW performance is very poor / unusable. On a paddle it misses or inserts characters and macros stop partway through 75% of the time. I have updated the firmwares and still no improvement any suggestions to improve this.

Hello, when I follow the link via wiki and git, proton says no file avaliable. Did I follow wrong link or is the img not more to download? Please advice. 73, Michael

Hi, Just some ramblings... The test sheet with the Zbitx states -105 dBm is the minimum signal. I am not sure how this is measured. I found it difficult with the chuff/chuff of screen update, so by ear I listened to a very weak carrier (from a signal generator) of -105 dBm which appeared on the noise level (with display set in menu mode to minimise chuffing) I extended the display board away from the RF board with Arduino Male-female test leads so I could do some testing I looked at the datasheet of the WM8731 and it said the S/N ratio was -90dB for a FSD level of 1V RMS. The is about a 32uV noise floor. After doing some tests with the display extended away from the RF board, I was able to determine that the gain of the low IF amplifier was in the vicinity of 72x and that the RF Gain/Loss from RF input to that section of the board was about -8 dB as best as I could determine. The low frequency section appears to have a 50ohmish input Z, so 32uV/72 is about 0.45uV at 50 ohms or -114 dBm. With 8 dB loss added to that, the noise floor would be about -106 dBm. I figured that I could try some extra gain to bring the input level up. This was done by adding a 27 ohm and a 4.7uF tantalum from Q8 emitter to ground. This increased the gain, but had a marginal increase in sensitivity. (possibly due to earlier gains/losses) I looked at Q4, the 40MHz RX amplifier, and it was running at about 2.3 mA emitter current, vs the TX side Q3 amplifier which calculates to around 19mA. I decided to change the R27 base resistor from 470 ohm to 1k ohm which increased current to around 8.5 mA. I found I could now hear carrier around -114 dBm now, which is probably due to both the 40 MHz and Low IF gain being increased. It affects the S meter readings. I haven't done any measurements of impedances of the 40 MHz amplifier, and would have to try a breadboard setup to determine that. I think the 2.3mA emitter current on Q4 is probably marginal for a RX IF preamp. The increased gain will also affect the maximum signal that the receiver can handle. Tests were done on the RX front end with a signal generator at high-ish level, and a -20 dB RF probe, into a TinySA Ultra. The tests at the low IF were viewed with a oscilloscope in x1 mode. Clipping appeared on Q8 output at about 3v p-p, probably due to the 3.3V zener clamp. Thoughts anyone... Kevin

I got my zBitx in great shape delivered a few days ago. I am wondering what is causing a beeping noise on my transmitted signal on SSB. I tried both internal and external mics and problem is the same. SWR is great and Battery voltage is 7.6V. I tried using 18650 batteries as well as an external power supply running about same voltage. Any ideas?? 73 de K0NEB

Hi to the group, I am new to the Sbitx and was following thee directions to check for updates and i got an 'fatal error' No such file or directory, #include oled.h When I rebooted the radio it now has no delay in CW relay click and clatter and no delay. Again it appears to be breakin mode. Not sure what to do to fix it. I may need to reload the software, if that is the case -- what are the commands to do that? Thanks in advance -- Rick W7RNB

https://www.ke9a.com/remote-zbitx-demo/

I tried to upgrade the original Buster 32-bit distribution using sudo apt upgrade. After rebooting I get the error message: sbitx: simple.c:649: snd_mixer_selem_has_capture_switch: Assertion 'elem' failed Is the original distribution image available on the web to reprogram the SD card? Can the zBitx software be compiled for a standard Raspberry OS distribution? Thanks, Jim N7IHQ