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UPDATE - sBitx V3 with Firmware version 5.4
So the dev team working on the sBitx software suite (unpaid I might add so I suggest you drop in on them and give them a donation for all this time and enegry they have put into this for the community) has dropped ther latest version of the sBitx SDR firmware and it is version 5.4 and let me tell you, this is incredible!
Highlights of the new firmware for the sBitx Software Defined Radio
This is taken directly from the drexjj GitHub repo page so I dont get something wrong. Goto this link to see more about this project and to help support the team.
Here is the list for JUST THIS RELEASE!
v5.4
New Features:
sBitx IQ improvements
enhanced VFO, complex mixing and down-converting
improved processing of I and Q data in the sBitx receiving pipeline
AGC function and AM detector changes to work in updated pipeline
FM Mode and Squelch
Added FM mode and squelch control for use on 10M and transnverters
Text console can scroll back to view and work with up to 500 lines of history, in all modes
Added support for Touch Display 2 and larger displays
Makes it easier to touch and see the buttons on a Touch Display 2 or external display
New file is read upon sbitx startup called display_settings.ini where you can set the display type or resolution
display_type=1 is for the original, older 7 inch touch display
display_type=2 is for the newer 7 inch touch display
ui_scale can be changed for use with a larger display
Added styles option to customize the sBitx application.
Text size, font, color, and types are now supported.
Styles templates are stored in the data folder as tpl files.
If there is a file named user_style.tpl in the sbitx data folder, then it will load it on sbitx startup.
If the user_style.tpl file is not found then it will load default_style.tpl if it is present.
If none of these files are located, then it will load the factory style we are all used to.
There are sample styles in the data folder that can be loaded. Just have to rename one of them to user_style.tpl
Added mode_bal to hw_settings.ini to balance LSB and CWR to USB and CW.
0.8 is a reasonable value.
Also harmonized filter band edges.
removed old ssb_val
Controlled Envelope Single Sideband (CESSB)
enable via the button in menu 1 or the 'cessb on' command
Added Tune function to FTx modes
Added NBFM mode with CTCSS and Squelch
Added squelch control to AM mode
Added option to use USB audio devices for sound routing (speaker/phones and mic input)
The options are in the Set dialog box in Menu 1
Added Out-Of-Band and license class indicators
Shows color strips or shading for bands edges and US license class
Each file can be customized outside the USA
More details and instructions in the oob_limits files in the data folder
Added ALC power limits by band, if RF power exceeds limit it is folded back to limit
Default is off until a limit is set in hw_settings.ini by adding line max_watts=nn to band data after f_stop
When activated message is given in spectrum between Power and VSWR
Power reduction is released when RF power drops below bamd limit
Added swrsweep
usage: select a band then either
enter cmd swrsweep n, n where n is the number of sample frequencies or
in menu 1 set SWRSTEP to the number of samples and click on SWRSWP
uses TNPWR to sample vswr at the n sample points evenly spaced between band limits
displays results in console
esc key cancels sweep
Added time out feature to SWR alert
SWR alert ends after 10 seconds without needing to first transmit with SWR less than max_vswr
Added HPSDR 'Protocol 1' support to provide sbitx I and Q data to external SDR apps over WiFi or ethernet
Starts when sbitx starts, console will show "hpsdr: streaming STARTED" when SDR app discovers and connects
Good support for SDR app receiver functions
XMIT not yet supported, will require CAT/Hamlib connection
Changes:
GUI
Moved Direct Frequency Keypad to a new button called PAD and added quick buttons
Swapped button placement on main display
Moved eptt & vfolock to menu 2
Menu 1 is reserved for mostly audio related controls
CW Decoder
Fixed colors of sent and received text on console, use new lines when doing T/R switch
Only displays cw stats (WPM, dot/dash ratio) when they are meaningful
Less garbage ouput when only noise is present
Replace sliding window in denoise function with EMA filter
Improved accuracy with better weak signal performance
Replaced viterbi with simpler classifier
Simplified code of own TX decode process
Set BW to 50 when using decoder is recommended
Web interface
Added more controls
Gridmap new options: Square or round Grid dots; Seen Grids; Unlogged Grids;
Power and VSWR readings updated more often, from every second to every 1/2 second
Updates are now as fast as bridge reads allow
Minimum power for VSWR calculation increased to help eliminate invalid reads at very low powers
Fixes:
APF init Bug
Fixed a bug where APF would not initialize properly
Audio Cleanup
Made a small change to cleanup the static between TX to RX
APM sampling improved for better regularity
VSWR initialization when user disabled fixed
max_vswr=0 now restored as no max vswr protection at startup
Fixed scope intensity where it now loads and restores previous setting
Fixed Macro loading and F1-F8 buttons when changing modes
Web Gridmap red Grid dots now shown when QSO is logged
Fixed expansion of SENTRSTCUT in macros
Downloading and burning an image to your microSD card
Firs thing you need to do is go download the new image. The new image is a zip file so you have to extract it and then you can move on to step 2… This is where you use a tool like Balena Etcher to write the disk image to a micro SD card. I use 32GB cards since it is what the radio started out with. They seem to work just fine to be honest. I did have to write the image twice for some reason. The first time the image would not boot past the splash screen so I re-burned it and then it worked fine. Balena Etcher is an easy to learn tool that makes this process pretty simple to be honest. If your using Linux it might take a little to get it running, but google will tell you what to do here as well. I ended up running it in my terminal so I could shutoff the sand box feature. I know this is probably a bad idea to remove the sandbox but I have confidence in Etcher so I am good with it. Launching it from the terminal, you are presented with this panel. The first one is where you choose the disk image you want to burn, the second one chooses the media (hard drive, memory card or the like) and then you click flash and wait… It will take a few minutes and you are presented with a ready to use version of the sBitx software ver. 5.4. You still need to copy a couple of files from your existing version of the sBitx you are using. It is not a big deal to do this as you just need to copy them to a USB memory stick so you can later put the back when you swap micro SD cards in the radio.
The next step for me, involved me taking my radio apart some what. I use the on board Raspberry Pi micro SD card slot on the Pi. This means I have to take the front of the radio loose from the chassis and open the radio enough to be able to swap out the two sd cards. Dont make my mistake and use the same card for both images. Make sure you use a new card for the new image and save the old one in case something goes wrong so you can go back to the working version while you solve the problem. This is pretty easy and only requires you to remove 4 screws to succeed. Once the new card is installed, you are off to the races! Just power up the radio as normal, being sure to have either a dummy load or a tuned antenna attached as it will auto launch the radio app and if it is on FT8 it just might start answering a CQ if your not ready! HaHa! The card really is easy to reach, just be careful to not unplug anything like the video cable you see right next to the card. I have my cable wrapped in copper tape and grounded to help reduce RF hash from the Pi, this is a hack that actually works really well. This cable is one of the prime culprits of rf hash in this radio so just doing this one mod will improve your experience a lot.
This is the new splash screen that you are greeted with while the software package loads everything. I really like this new look the dev team brought to this release. Once the software loads, it will auto launch the sBitx radio app and you will have the view below. It is in FT8 mode here since I was last using this mode and band. There are some things you need to do before you start using the radio, such as entering into Menu 1, then touching the “Set” button and in here you will enter your callsign and grid locator you are currently operating in. This is used for logging and digital modes. But it helps to do this first thing so you dont forget. I also keep a note about this in my case so I dont forget to do this step when I am out traveling and activating POTA parks with this radio.
Personal thoughts about the HF Signals sBitx SDR radio
I only use my sBitx for a couple of modes. FT8, FT4 and CW. I rarely use SSB or any other voice mode for that matter. I just prefer CW to be honest. That being said, I tested out the keying on the current release and it works perfectly for me. I normally dont run over about 22WPM though so if you work faster than me, just know I wont be speeding up with this radio…lol. I can get decent code out of it at 25WPM, but now we are getting into the realm of my skills not being up to the task too… sooooooo. I dont know which is to blame past this point.. HAHA!
I like FT8 as it will work when the bands seem to be closed for even CW. That is nice if you are activating a POTA park and the band closes on CW with 8 calls in your log. This way I can hop over on to FT8 and more often than not, I will get those needed calls in the log and probably more, in spite of the fact that the output power on a band like 15 meters will only be about 12 to 15 watts depending on battery level. I can get a lot more output power on the low bands but on the higher bands I will not get a lot of power out. This just further solidifies my stance on using FT8 in poor band conditions and the ability to make contacts with it natively in the radio. I would like to say something else about this radio. I really like the community around it. Sure there will be the occasional disagreement here and there. It is a group of humans after all… But for the most part, it is a group of experimenters and coders and general operators that love to tinker with their machines as much as operate them.
Speaking of images on disks. Over the last few years I have amassed a small collection of different images. You might think this is silly, but there is a method to this madness. You see, for one, I have a full collection of images starting with the factory shipped version that came with the radio. The factory version is the one with 381 written on it, as this is the serial number of my radio. I have a copy of the Field Day release and the first 64 bit release. As time passed and new versions were released, I get them and burn them to a new card and save the old one. I can install any one of these cards and it will instantly become that version radio again. That is pretty cool. Honestly though, the other reason I keep them all is that there is logbook data stored on them as well as the later versions all have my config files on them that I can get to should the card in the radio die for some odd reason.
Another really good idea for a person getting one of these radios is to use the disk copier app and make a backup of your image on a new micro SD card. This way should the one in the radio die, you can simply replace it and keep going…right after you make a new back up. The reason I keep circling back to this is that these card are not the most reliable on earth. All of mine have worked well, but there has been some people that have had their card get corrupted and dont have a backup. That is tough spot to be in to be honest. Anyway, I thought I would share a little about one of my favorite radios and what is going on with it.
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73
WK4DS - David
Chito Branch Reserve: First FT4 Contacts, Meeting a Fellow Park Hunter, and the Quest for 1000
Doug's been activating Chito Branch quite a bit lately, and if I'm being honest, we seem to be in a friendly race to see who hits 1000 contacts from this park first. Spoiler alert: he's winning. But it was great to finally shake hands with someone who understands the appeal of spending beautiful Florida mornings in a park with Spanish moss hanging from the trees, headphones on, working the world.
February 10, 2026 • US-5524
Sometimes the best part of a POTA activation isn't the DX you work or the pile-ups you run! it's meeting another operator face-to-face who's been chasing the same goals you have. Today at Chito Branch Reserve, I finally got to meet Doug, KQ4SXW, in person.
I finally got to meet Doug, KQ4SXW
Doug's been activating Chito Branch quite a bit lately, and if I'm being honest, we seem to be in a friendly race to see who hits 1000 contacts from this park first (well, between us at least). Spoiler alert: he's winning. But it was great to finally shake hands with someone who understands the appeal of spending beautiful Florida mornings in a park with Spanish moss hanging from the trees, headphones on, working the world.
The Setup
I rolled into Chito Branch mid-morning with my usual portable arsenal. The park is close to where I'm staying in Tampa, which makes it an easy choice for activations, and I've been systematically building toward that 1000-contact milestone. As of today, I'm sitting at 769 QSOs logged from US-5524, so I'm getting close.
For antennas, I ran my 1/4-wave vertical with two counterpoise wires, tuned for each band. Simple, effective, and quick to deploy. I use the nanoVNA to utne the antenna with. As you can see in the plot above, I get it to something less than 1.5:1 SWR and call it good, I have found that if I get it to that level that I dont have any trouble making contacts at all. I have done OK with the SWR higher in the past…much higher actually, but it is a lot tougher to make contacts like that.
The main rig was the sBitx V3 from HF Signals for digital modes, and I brought along the Ten-Tec Scout 555 for some 15-meter CW work since the bands were looking promising.
Speaking of which… let me tell you about my grid square insurance policy.
A Sticky-Note Solution to a Real Problem
If you operate FT8 or FT4, you know that your grid square locator needs to be correct. It matters for awards, for logging accuracy, and frankly, for not looking like you don't know what you're doing. Recently, I completed an entire activation with the wrong grid square set in the software.
Not ideal.
Sometimes the best solutions require the simplest answers…
So I came up with a foolproof solution: I now keep a note in my radio case that says "FIX GRID BEFORE USING FT8." It sits right on top of the sBitx when I open the case, impossible to miss. I also store the Bluetooth keyboard in the case with the radio so I can easily update the grid square in the field without fumbling around with the tiny on-screen controls.
Is it a high-tech solution? No. Does it work? Absolutely. Sometimes the best fixes are the simplest ones.
Starting with FT8 on 20 Meters
After getting the sBitx fired up…with the correct grid square, thank you very much… I started the activation with FT8 on 20 meters. I spotted myself on POTA and the responses started rolling in. There's something satisfying about watching those waterfalls fill up with decodes and seeing callsigns appear in the queue.
My very 1st FT4 QSO with the sBitx!
I worked through a solid session and logged about 18 contacts on 20-meter FT8. The band was cooperative, signals were good, and the activation was off to a strong start. Something to note about my sBitx V3 is that it has developed a sort of internal noise on 20 meters that lingers in the CW portion of the band. It goes down in frequency as the radio warms up so I have to figure out what is causing this problem when I get home the next time. I have it on the list right next to fixing my microphone pre-amp circuit for proper operation as well.
First FT4 Contacts at a POTA Park
After the FT8 run, I decided to try something new: FT4. I've run plenty of FT8 from parks, but FT4 was uncharted territory for me in the field.
FT4 is faster than FT8, cycling every 7.5 seconds instead of 15, which makes it great for contesting or when you just want to move quickly through a pile-up. I updated my spot on POTA again and started calling CQ. To be honest, I had used it a little in the shack before with no luck so I didn’t hold my breath today, To me utter surprise, I saw a QSO forming in the call feed on the left! Then it finished and logged it! I hurriedly got out my phone and snapped a quick photo to share with you guys…
First contact: AA5WH on 20 meters. Clean decode, solid signal, contact in the log. Then I switched to 15 meters and worked N1KLF. Two FT4 contacts, my first ever from a park, and honestly? I was pretty stoked. There's something satisfying about trying a new mode and having it just work.
15 Meters CW Was Alive
The TenTec Scout 55 is pictured with the HF Signals sBitx V3 where I was changing over to CW after working 2 digital modes today.
After the FT4 session, I switched gears completely. I packed up the sBitx and pulled out the Ten-Tec Scout 555 for some CW on 15 meters. The band was in great shape, though there was a bit of QSB rolling through. I got the radio all connected up to the keyer and then plugged in the Travler. My Begali Traveler key has become one of my favorites—smooth action, compact enough for portable ops, and it just feels good. It is sensitive, but that is how I use my keys, I prefer a light action myself and that is why I made my own paddles back in the day. N3ZN (Tony) and I2RTF(Pietro) make some of the nicest keys around at the moment and I am glad I have one from each.
DX Contacts That Made It Worthwhile
Right out of the gate, I snagged some DX that made the whole activation worthwhile:
EA4MZ in Spain
DD1LD in Germany
YV1GIY in Venezuela
PY5XT in Brazil
Four different countries, all on 15-meter CW with 40 watts and a telescoping 1/4 wave vertical, what more can you ask for? Days like this remind me why I love this hobby. Some of them were a little on the weak side but the Jones filter in the Scout actually helps if you open it up instead of closing it down. This seems counter intuitive, but opening the filter up just ever so slightly will let a lot more of the other operators signal though and just a little of the background noise, it is almost like having them turn their power up 50% or something, if you have not tried it with your Scout 555, I suggest you find a signal you can barely hear and give it a shot.
43 QSOs and Counting
By the time I packed up, I had 44 contacts in the log, though one turned out to be a duplicate, so 43 that counted. Not a huge number, but solid for a few hours of casual operating across three modes (FT8, FT4, and CW) and two bands.
Meeting Doug in person was the cherry on top. It's always good to connect with like-minded people in the hobby, especially when you're both chasing the same quirky goals. A thousand contacts from one park? Yeah, it's a bit obsessive. But things like that are what makes it fun.
SIDE QUEST TIME:
I ran into a unique problem today that is worth mentioning here. I was charging my computer with an inverter that I have wired into the cab of my truck. I was also running the truck so I could power the inverter and charge the computer as well as the sBitx V3 at the time. Well it turn out that I have some issues with this inverter that need resolving. The next few photos show the RF hash that this inverter is producing when under load! It is unreal how bad it was, I couldn’t believe all I had to do was simply shut off the engine and unplug the power cord from the logging computer and it went completely away…
The above photo shows the hash of running both devices on the inverter with the engine running on the truck.
The next photo shows what happened when I shut off the truck and unplugged the computer.
The last photo shows what the band looked like once I went around to the other side of the truck and powered off the inverter completely. This goes to show that you need to check these things if you plan to use RF devices like radios in the presence of RF trash generating devices like this inverter… Better inverter coming up!
END SIDE QUEST
Hit me up!
231 contacts to go until I hit the big 1000 from Chito Branch. At this rate, it'll take a few more activations, but I'm not in a hurry. Well, maybe a little… Doug's still ahead of me.
If you're in the Tampa area and see someone set up at Chito Branch Reserve with a vertical antenna and a tablet running digital modes, stop by and say hello. Chances are it's either me or Doug, and either way, you'll be in good company.
**Gear Used This Activation:**
- **Radios:** HF Signals sBitx V3, Ten-Tec Scout 555
- **Antenna:** 1/4-wave vertical with dual counterpoise wires
- **Key:** Begali Traveler
- **Digital Mode Software:** JJ and the sBitx 64 bit Development team version 5.301 (FT8/FT4)
- **Computer:** Dell Inspiron with Linux and HAMRS
- **Accessories:** NanoVNA for antenna tuning
Have you tried FT4 for POTA activations? What's your go-to mode for portable operations? Drop a comment below or find me on Facebook or shoot me an email on here.
What is FT4 and how is it different from FT8? FT4 is a digital mode similar to FT8 but with a faster cycle time (7.5 seconds vs 15 seconds), making it better suited for contests and quick pile-ups.
What equipment do I need for POTA FT4 activations? You need an HF transceiver capable of digital modes, a computer or tablet running WSJT-X software, an interface between your radio and computer, and a suitable antenna for your chosen bands.
Where is Chito Branch Reserve located? Chito Branch Reserve (US-5524) is located in the Tampa Bay area of Florida and is part of the Southwest Florida Water Management District.
How many contacts do you need for a valid POTA activation? You need a minimum of 10 QSOs to qualify for a valid POTA activation.
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73,
David WK4DS
I used Modern Digital Modes and I have mixed feelings.
Well, it finally happened. KV9L helped me setup my computer at home to work some digital modes with my IC-705. It turns out that all I needed to connect my IC-705 to my desktop PC was a simple USB cable! It also took a significant amount of “know how” from my buddy Aaron to get them talking to each other as well. The two modes that I have played with so far as FT4 and FT8. These seem to be the current hotness in digital modes with FT8 clearly winning in popularity as the “watering hole” for it on 20 meters has dozens of stations on the air pretty much 24/7. The FT4 area can go long periods of time with no one there at all. Just to see if I like this idea, I have just wired the 705 up temporary on the shack bench with wires running this way and that… Once I decide if I want to keep this up or not, I will put all those pesky wires away…but till then!
All I needed was a USB cable that was in the storage bin 3 feet away…lol.
I will be honest though, I am kind of stuck in the past. I really like the kinesthetic feel of working with my gear and once setup, these new digital modes are pretty hands off. I was blown away at how far I could hear stations that are not even perceptible to the ear when using the “main two” modes (SSB & CW).
I was hearing stations from all over the world on my simple vertical antenna. Here comes some of the problems though. They either wouldn’t answer or couldn’t hear me when I would click on them. That isn’t to say that I didn’t make any contacts but it is not as easy as I was thinking it would be. Often I would choose a station to answer just to have them continue to call CQ.
Another thing I learned was that there is a good bit of waiting… Actually, there is a lot of waiting… it takes 15 seconds on FT8 to send one message, in one direction, and another 15 to send the reply. A typical QSO is 4 messages(as best as I can figure) from each person so a full two minutes to finish one QSO. This doesn’t sound like a long time till you are sitting there watching the QSO happen in real time. It goes a little as follows: they call CQ, you call them for a QSO, they don’t hear you the first time as you started transmitting in the middle of a cycle, so they call CQ again, then your message is repeated, they accept your call and send signal report, you send signal report back, they acknowledge and 73, you close with 73…all automatically. Each one of these is a full 15 seconds of waiting since the computer is handling everything for you. If the band is crowded and noisy or you are like me, running QRP power, the exchange can take multiple attempts to complete each stage (all of this is also automated), running the total time up even further.
Here is an example of a QSO I had with KP4PUA in Puerto Rico and notice we had to send signal reports twice to complete the QSO, This took a full 2 minutes to exchange this simple contact.
Another thing that happens is they give up after three of four attempts at the QSO. Burning a full 5 minutes or more just ATTEMPTING to complete a QSO. So I tried several times and made maybe a dozen QSO contacts over the past couple of days. This ends up being very frustrating and to be honest…boring… for a CW op who is used to things happening differently. I found myself picking a callsign for my computer to attempt to call and then leaving it to make the QSO and going for snacks, water, or even a bathroom call and just checking for the complete QSO window when I returned. It is a fully automated process and requires nothing from you other than to click the ok button and choose another callsign.
A typical window layout for FT8 (pictured) or FT4. Click on the screenshot to goto the WSJT-x webstie to learn more about it.
I can see the value in It though, as it takes very little energy and lots of stations can fill the same bandspace as a single SSB QSO. I mean a lot, like dozens or maybe more as shown in the waterfall above. All of those little yellow squares are exchanges happening and they are taking about 100hz of bandspace and they can also duplex and share the bandspace at the same time…from what I can tell. So it has merit, just not for an old CW op like myself.
Now to be honest, FT4 is more my speed as it took half the time to send each message. Waiting 7 1/2 seconds seems like a trivial amount of time difference, but it does seem to pass be faster than the 15 seconds of FT8 for some reason… Like disproportionately faster. Even though there is only 7 1/2 seconds difference, it just seems like it is 4 times faster for some reason, it must be a mental block or something, but that is how I see it. I have been letting it run on FT4 while I typed up this blog post and actually made a few QSOs while I have been here. Not many as FT4 is not as popular as FT8 for some reason and there are not as many people using this mode.
So who do I think this mode of operation is for? That is a great question. I would guide the new ham to it, as once setup, it is very simple to operate and you don’t have to worry about “mic fright” as it is literally point and click. Another group that would be well served right away is the younger generation as they are accustomed to this type of interface and for them, it would “just make sense” for them as they are used to using computers all their lives. Another group would be the person that has been injured or incapacitated in some way that prevents them from using the usual modes, as long as they can drive a mouse, they can get on the air. Shoot, if you just like using digital modes, then it is there for you! There are others of course, my point is that I am not bashing digital modes here, I have just found it wasn’t what I expected and that it isn’t really for me…at this time. I hope to be able to add a computer to my activation gear list at some point and that should enable me to add digital modes to my activation tool kit. I carry a microphone now, but rarely use it, and that needs to change… I really enjoy quietly sitting in the park working CW though, so I am torn… lol. Anyway, till then I will keep using my little QRP radios and having a grand ole time. If you have not gotten out and activated a park, I highly recommend it. I am going to write up what I pack for an activation, and that is my style, and share that with you soon.
If you want to learn more about Parks on the Air. Click this link or the photo below.
Me working the OG digital mode…CW on my tiny N6ARA paddles