27 December 2023

sBITX V3 Board Review

 A few months back Ashhar Farhan VU2ESE, the father of the BITX series of QRP transceivers came out with the latest edition of that line the sBITX. Once I checked out the copious number of attributes of this little, I immediately realized that this is the HF Transceiver that I have been waiting for. It first came out as the sBITX D.E. (Developers Edition) this edition was to help iron out all of the little problems that come with launching a new product. 

The sBITX DE may have been mainly for ironing out problematic issues, but it proved to be capable of paving the road for the sBITX series. The future and pretty much the present of HF transceivers is SDR- Software Defined Radio. An SDR is in layman's terms, where many functions of transceivers is performed by software instead of traditional electronic components. This allows the physical size of the transceiver to remain small and at the same time expanding its features. What Farhan did with the sBITX DE was genius. He took a relativity cheap (at the time) single board computer the Raspberry Pi 4 and incorporated it into a custom built 40-watt HF Transceiver. He then made the transceiver, and 

Raspberry Pi OS open source and made everything freely available for anyone to download the software and hack it and change it in any way that they see fit.  

The sBITX DE covered the 80, 40, 30, 20, 17, 15, 12 and 10 meter bands. It was about the size of a bread toaster. It incorporated a Raspberry Pi 4 (2 gb) and a 7 inch Raspberry Pi touch screen. By having the Raspberry Pi fully incorporated into the system, a whole new plethora of features that are not even seen it transceivers costing ten times as much. 

Digital modes has been a large part of the hobby for decades. Usually you need to have an HF transceiver, a computer and some sort of interface that connects the transceiver to the computer. On top of that you need all of the cables that come with the computer, all of the cables that come with the transceiver and the cables required to connect it all together. The sBITX gets rid of most of that mess. You need a power cable and a antenna coax. That's it. Yeah a keyboard and mouse are great additions to the sBITX (does your expensive HF radio use a keyboard and mouse?) but with the Raspberry Pi, those can be wireless. So without any extra devices, cables etc, the sBITX allows you to operate on most if not all digital modes. To help you keep track of all of the QSO's that you will have with this rig a logbook is also incorporated into the system. In some modes it will do all of the logging for you on its own! As we all know, we like to brag about getting some rare DX in your logbook. A lot of the time your buddies will just have to take your word for it. The sBITX now allow you to back up your bragging with the ability to record that QSO and play it back to your envious friends. 

One of the sBITX features that i really love is CW. It is well known that I have a host of medical problems. Some of those problems are neurological in nature. These neurological issues keep me from sending CW via key, paddle, bug and most other devices. I can type decent enough though. There are a few ways to send CW via keyboard. Usually in the form of an expensive keyer that has a keyboard feature as an afterthought. The sBITX really makes my heart thump with its options at sending CW. You can send with a straight key, a bug some paddles, and of the traditional stuff. Also you can have a keyboard on the 7" touch screen where you can send by using the on screen keyboard. As mentioned earlier you can use a wireless keyboard and mouse with the sBITX. So of course the coolest option is you can send CW with the wireless keyboard. The CW signal is decoded on the screen as a back up to you decoding it yourself. 

The first edition for public sale was the sBITX V2. This offered all of the features of the DE edition but the depth of the enclosure was cut down by more than half. The new version was about the size of the ARRL Handbook This made it much more friendly for POTA, SOTA and other portable activities. 

You can pack up the sBITX, a battery and antenna and get out of the shack and go out to a local park and get on the air. You wont need any extra parts like a computer of fancy keyer to show all of the passer by how cool amateur radio is. Also you can use your cell phone as a hotspot so you can use THIS HF radio to catch up on Farhan's latest YouTube video or you can cruise on over to the BITX 20 io group to ask any question you want about any of the BITX radios. The sBITX comes pre loaded with the Libre Office suite of software, so when the bands are dead you can make a antenna measuring spreadsheet on LibreOffice Calc or you can use LibreOffice Writer to write your next best selling novel. Can you write a book on your two thousand radio appliance? Didn't think so. 

The latest edition is the sBITX V3. This is the one that I am blessed to have. I have the board only version where I had to supply the Raspberry Pi, 7" touch display, speaker and microphone. 

The V3 has a new gui (Graphic User Interface) however the V3 operating system and sBITX software will work on the DE and V2 versions. Instead of transmitting 40 watts the V3 has a more respectable (to me at least) 20 watts. 

Now I have put my V3 through some use and racked up a few new countries. Here is my setup, but your mileage may vary. 
  • sBITX V3 transceiver board only (I really need to figure out an enclosure for it before something gets shorted out.) 
  • Raspberry Pi 4 (4 GB RAM) 
  • ATU-100 EXT Automatic Antenna Tuner, I really do not need this (see antenna below). I'm mainly using it as a power/ swr meter which again is not needed at when transmitting the sBITX displays the transmitting power and the SWR. 
  • 20 Meter homebrew Inverted V dipole broadside east-west. The feed point is 32' above the ground. I have it tuned to 1.0:1 - 1.1:1 SWR on the CW and Digital portions of the band (14.000-14.200 MHz).
I do not have a dedicated room for my shack. My house is fairly small and there are four humans and a cat that call this place home. My "shack" is one wall on the side of my bedroom that I share with my beautiful XYL. We have been married since June 1997. To have a long lasting happy marriage both parties must be willing to compromise. Saying that me and my wife have two different sleeping patterns. My wife likes to sleep in late and decades of work tuned me into getting up a couple of hours before the Sun. So I make an extra effort at being quite so my wife can sleep. To make this even more challenging, I'm mostly deaf and I live in my bed, so getting up and going to another room is generally not an option. So I tend to lean towards the quieter modes like CW and digital modes there I can wear head phones. Typically we still have to put up with the sound of a fan keeping the finals cool on the radio and of course the ever present clacking of the relays. Well the sBITX has neither of those. Operation is really quite. You can hear the electricity flowing during transmit but that isn't really loud enough to be a bother. I was having a problem with SWR. The radio would dial down the power to one or two watts, the SWR was being displayed at 25:1 and higher. Every time I would transmit the computer monitor that I was using for a display for the sBITX would shut off. It was driving me crazy. The antenna kept measuring a perfect 1:1 SWR. After several days of looking for the problem (Remember because of my health I could search for just a little bit at a time so what would take a healthy person a few hours took me days) and I finally found the problem as being a loose coax connector. Once I got that tightened up, the sBITX has proved to be better than I even dreamed that it would be. I use a 15" computer monitor instead of the 7" touch screen display. The reason for this is entirely because of my eyesight and has nothing to do with the radio. I'm due for some new eye windows so that problem should go away. I have been mostly on FT8 and I'm not used to having such an awesome waterfall display. I still have a lot to learn about this awesome radio and I bet I'm going to be enjoying the learning process. You can go ahead and view the sBITX as the new radio on the street. To me it the ONLY radio on the street. I plan on pushing this radio to the limit and I'm sure even at a proper QRP level of 5 watts the sBITX is going to make my logbook fatter than my stack of bills. 

Over this winter I plan on having a few more surgeries to get some of my back problems ironed out. I plan on healing up in time for spring. The plan is for me to be able to start riding my recumbent trike again. Since I was last active on my trike Midwest City has built many new miles of bike trails and even a new city park. With the small size of the sBITX V3, I will be able to put it in my trikes saddle bags with a battery and some wire and go back to operating portable. Permanently mounted on my trike is a 23' telescoping fishing pole that is perfect at supporting a wire antenna. I recently was able to get a second matching fishing pole so expect me to add that to the trike to expand my options. I have already added a HT and a small dual band mag mount antenna. This is to let me talk to my friends while riding the trike. Also in the past I would go out and ride and hurt my back or have my blood sugar to drop to dangerous levels and would require someone to come and help me out or bring me to home or the hospital. On my trike I wear a small head set so I only need to press a single button to operate the HT and get into the repeater. I'm lucky that my mother in law and daughter have their radio license and I have many wonderful friends that monitor the repeater just in case for me. 

I plan on sharing my sBITX exploits here on this blog. I have many plans for it in the future. My brother recently moved into a house that is just yards from a state parks that will need to be activated. I have family that live on SOTA Summits that need to be activated. I can't wait to work the world with this little radio, its gonna be fun. So as always, feel free to share any comments or ask any questions in the comments section below. You can be notified of my adventure and any future blog posts simply by subscribing. Please email me (I get lonely) at Aaron@K5ATG.com

Until Next Time 
'72
Aaron K5ATG

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