开云体育

Working on learning satellites for a few months now, building most of the gear, instead of buying stuff. TODAY for the first time, I heard my own CW by way of the satellite, monitoring an sBitx (V2) using a Ukranian transverter (neither of which seems to be terribly sensitive). JO-97, in its pass over the eastern USA around 11AM Eastern time. Main rig was older ICOM820H transmitting on 70cm through a homebrew yagi/homebrew dual axis rotator system controlled by homebrew PCB using K3NG controller, controlled by SAT32PC. With some effort I found my signal on THAT setup with a CAT correction of 5kHz (I don't know why that is so far off yet) SBITX SECOND RIG was a sBitx crudely "tee'd" in with simple PL259-Tee, so it got the same signal as the Icom820H. I was unable to provide suitable doppler correction to the sBitx, because Sat32PC doesn't seem to know how to use hamlib; however, I could have done so using Gpredict directly to the radio (which was on 192.168.1.10 in this experiment; the antenna rotator is controlled over wifi using a raspberry pi) The spectrum display on the sBitx was a HUGE help. I could easily see my own CW on the waterfall and therefore tune to my frequency! I would say as a first cut that the sBitx and the 820H were running reasonably about the same as far as receiving. These passes are ONLY 10 minutes long, but on he Sbitx I could SEE other SSB conversations going on (and they seemed to have more power than my signal.....) -- so I could QUICKLY tune to them on the Sbitx and receive them just fine! On the Icom820H (without a spectral display) you have to tune up and down the band. Signal Levels: I have the antenna system 50 feet out into the driveway. The 70cm transmitter is going through 100 feet of LMR400 to a crossed Yagi homebrew. The 2meter downlink goes first into a diplexer to protect it from 70cm pickup (https://www.dxengineering.com/parts/cma-cf-416a) and then into an inexpensive GaAs FET preamp Moonraker M-100 Professional (https://www.dxengineering.com/parts/mkr-20-001) turned all the way up, theoretically 20dB gain. At that level, both the 820H and the sBitx/transverter hear considerably more SIGNAL as evidenced by increased background noise. Without the preamp I'm pretty sure the Ukranian transverter and sBitx would hear nothing, and I'm not sure about the 820H -- haven't gotten good records on that. My experience with the used Icom 820H is that I generally do best by keeping that preamp at +20dB. WITH the preamp I have heard amazingly good SSB signals -- like full quieting FM quality! The sBitx was showing MY cw maybe 10-15 dB above the noise baseline (IF was set to 84 on the 10 meter band) but my recollection is that the SSB signals were 20-30 dB above noise -- stronger than my CW signal. (So maybe I need more oomph on transmit???) This proves that you can use an sBitx as a satellite downlink receiver with transverter and preamp. In fact, it would be a very nice one because of the spectral display!! I think it would be easiest to use a second sBitx or other transmitter to do the transmit side, with a second transverter, and possibly an amplifier to get some more power.....I was surprised that my signals looked weak compared to what I heard from SSB stations on the satellite. Photos below Gordon KX4Z

BitXers, Been playing with and learning my new zBitx and I am having a blast. I have made a couple CW contacts almost immediately after receiving my unit. I had a couple unexpected hiccups in that I wasn't prepared for the "Mini-HDMI". The other was the USB-OTG adapter that came with it was bad. Fortunately I had another stuffed in a drawer and decided to try it. Keyboard came right up and I was able to get the unit up in Host mode. I paired up my bluetooth keyboard so I no longer have to deal with the USB port for that. I am running a portable 16inch (USB powered) monitor along with the wireless keyboard and can run the rig on either 18650 batteries or my Bioenno 1212Ah based battery box. Got the clock sync'd up and started up FT8 on 20m and made my first contact within in a minute.... Great start so far. It's not a KX2 but this little unit is a lot of fun especially with all the build in apps which I still need to play with. Attached is a couple of photos. -- "POWER, WE DON'T NEED NO STICKIN' POWER" - EVERY KX2 OWNER Always respect the airwaves, 73 de KI7PBR, Gary

To find the root cause of the spurs, I worked in 2 steps: 1. I took the front panel board out of the case and connected it with jumper wires to the main board. My objective was to eliminate possible EMI from the Pi Pico into the RF board. This did not make a difference for the spurs, as they just went down by 0.5dB which is the resolution of the TinySA. 2. In the si5351v2.c code I changed 8MA to 2MA. This results in approximately 5dBm less output power (33.5 vs 38.1dBm) but also a relative reduction of the spurs by approximately 7.5dB from -28.1dBc to -35.6dBc: Reduced output power is most probably due to the fact that the zBitx uses a diode ring mixer instead of the KISS-Mixer used in the sBitx and the oscillator power to the ring mixer is provided directly by the SI5351 CLK2 output (in reality an MS5351). Also, the IF diode ring mixer gets its oscillator signal directly from the SI5351 CLK1, whereas in the sBitx there is a buffer amplifier with two 2N3904. It could be that the much higher load on the SI5351 outputs, results in some intermodulation in the SI5351, which finally shows up as spurs. Given that these spurs are a showstopper, to transmit with the zBitx as the spurs are not at least 40dB suppressed, I am looking forward to further investigation and direction by hfsignals. On Mon, Apr 14, 2025 at 11:39 PM, Ron, N6YWU wrote: -- 73, Joerg - DB2OO

Sbitx - antenna switch - swr/power coupler - antenna Previously radio showed power and 1.0 swr on 15, 20, and 40 meters with similar readings on the off board meter. As of this morning swr on the radio and the off board meter show high SFR 2 to 3:1. Removed the radio from the antenna line and replaced it with an antenna analyzer, it shows a perfect 1:1. Another radio shows 1:1 on the radio and the off board meter. Previously, maybe a month ago I had the same problem, spent time chasing down the antenna to no avail. Then one day all was well with no intervention at or in the radio. All bands that were workable for the antenna show the same behavior today. Trouble shooting help welcomed. Tim

After letting my zBITX sit unattended in Receive Mode for a while, the main RasPi CPU crashes. I have never timed it because I'm not just sitting there watching it. But it seems like it only takes about an hour or so to crash. I am not able to get a SSH connection to the main CPU at that time. The display CPU is still running at that time. While the device is warm whenever this occurs, I do not think that it is a thermal issue because if I disconnect and reconnect the power it reboots and runs fine. I have never stopped the sbitx application to see if something else on the RasPi could be causing it. I have SSH and VNC enabled, but I am not using either of those connections. I do not have anything else running on the RasPi. So, I really do not think that it is some other RasPi appllication. I think that it is probably a sbitx application memory leak. Don't see how something like a character array overflow would occur after just sitting there unattended for that period - nothing is being done on the GUI during that time. This crashing occurred whenever I had version 3.021 installed, And it is still occurring with version 3.052 installed. If you are running on batteries, the batteries may be depleted before this crash occurs. You will never see it. I am using a 7.5vdc power supply. 72, Jody - K3JZD

I just received my zBitx, and have read the manual as well as been following this group for the past couple months. I hope to use this rig primarily on CW and perhaps a little FT8. I am aware of some serious CW issues having been noted on this group. What is the current state of usability in CW? Is there a best firmware to be using? I prefer to use an external paddle with the internal keyer and sidetone, but will a straight key or keyboard CW be better for now? Or do I just need to wait for a fix? I will power the rig with 18650 cells in the attached holder. What is the best way to turn off the rig? Remove the cells? I know that can corrupt SD cards… 73, Steve AK0M

Hi, I am looking for a nice metal replacement knob for the ZbitX. Would be nice if it had a tuning dimple or knurled edges. Prefer a vendor on eBay, Amazon, or Mousser or someone in US. Has anyone replaced theirs? Regards, Everett-WB9FUW

I picked up a zBitX at FDIM, but am just now getting it going as I had a backlog of storm-related stuff to deal with on the farm when I got home. So far it seems amazing. I have scanned the manual and have been reading postings, but this issue doesn't seem to be covered anywhere. In the photo below I am listening to 7.255 LSB and the signals are loud and strong and you can see the waterfall trace, but the red line for the carrier point is about 1500hz above the frequency, so the signal trace is offset in the indicated pass band. Is there a way to adjust the waterfall? Also, is there a way to increase the contrast for signals on the waterfall? Those there are nowhere near the intensity shown on other SDR devices, or maybe it is because the background shows a higher noise level? =Vic= \\

Hi! More work following the path that Ashhar suggested. I have also bought an older Icom 810H that has full duplex VHF/UHF. I'm doing initial experiments on Windows PC, but I have already demonstrated full Doppler shift control of sBitx acting as the 10m transceiver to a transverter, so this can all move to the sBitx.... GPREDICT re-installed due to better location, tracking any satellite I like. Does all the trig and doppler MATH RIGCTLD - previously studied and working; receives tcp/ip commands from GPREDIT to do doppler shift adjustments of sBitx or Icom radio Today: ROTCTLD -- figured out how to run this on a windows machine. Receives trig output of GPREDICT. Converts (in this case) to Yaesu type rotator commands for Az/ elevation and sends out serial port (in my case, COM4, 9600 baud) K3NG Rotator Controller -- I havent made a board for this yet. So I took one of my homebrew WINKEYER ARDUINO simulators, and reprogrammed it using K3NG code to "act like" the controller, handling Az, El controls, reading the CW speed control as if it were an azimuth potentiometer; running the display and activating the "key" and "PTT" to rotate clockwise or counterclockwise. The reprogramming of my Winkeyer Arduino appeard to be a huge success. I properly set the pins to run the display, which worked FINE. It was reading the speed pot as an azimuth reading, and if I pushed "buttons" it would read different elevations. ROTCLD happily connected to it at 9600 baud, and the "rotator controller" accepted commands and displayed them. I was not able on the first test to monitor whether it activated simulated motor controls (key output, etc) -- but that will come. So huge success here and soon (days, weeks?) I should be able to lay out a board (many others have done so before me, but some just did crazy wiring between variuous "shields") to put all this in a neat little package with relay outputs, possibly with PWM output (dunno)., to control available rotators for real. 73 Gordon KX4Z