开云体育

My operation was strictly CW because I accidentally left my microphone at home. (I use a modified Baofeng microphone, which I modded myself because I bought the basic kit.) I also left the keyboard at home (Logitech K400 Plus, which also incorporates a trackpad -- it's the same model that?Farhan uses), which turned out to be a serious mistake.

I was operating in a QRP contest so the output level was kept at 5 watts. If I had had the microphone along I would have turned it up to 10 watts for SSB (the NJQRP event allows that, some QRP contests do not), but that likely would have not headed up the radio any more than CW at 5W did. This is an unmodified rig that still has the LM338 regulator so I do not want to push its thermal limits; operating in a QRP event meant it was not an issue.

First, the good. The sBitx receiver works very well. Sensitivity was adequate for the 40 and 20 meter bands, which are the ones I used during this operation; the receiver could hear down to the noise floor of the band, which is all that is needed. I briefly?listened to 15?but there was no activity there; 20 wasn't great so I suspect 15 wasn't open at all. The audio quality is excellent. The flexible filters are effective and easy to adjust. The two encoders both work well; tuning the rig and operating the other controls is mostly simple. The transmitter got out well; I only made a few contacts due to poor band conditions, but it did the job for the ones I did make.

Next, the bad. I couldn't find a way to type numbers on the on-screen keyboard, and since I had left the physical keyboard at home I was unable to enter commands like setting the time (which I would have needed to do to try out FT8) or to use it to send Morse. (The capability is useless if you can't send call signs.) A real keyboard is also essential for setting up macros, so unless you meticulously set up your radio before a contest you'll need to have a keyboard along. Something about the internal iambic keyer, timing and/or polling rate, is off; I found it very difficult to send Morse with it, while I can easily do that with the same Palm paddle on my K2 or QCX. (I'm accustomed to iambic B mode and my other rigs are set up to use that, in case it matters.) The AGC made listening to weak CW signals unpleasant; it was far better to turn it off.?The T/R hang time after sending CW was longer than necessary.?The sBitx has no AM reception mode; I tried listening to some AM and shortwave broadcasts in SSB mode, which mostly worked well but AGC was an issue because with no carrier in the passband it was overly active.

I saw and heard some artifacts from broadcast stations. There is an AM station not far from my operating site so that was the likely cause. I couldn't tell whether I was hearing radiated harmonics from the station (there is no fix for that) or front end intermodulation products caused by the strong out-of-band signals (a high pass filter on the input would help). The signal from the nearby station was easy to receive even with the IF gain turned all the way down to ZERO and would distort if the gain was set much higher; it was STRONG.

As have others, I experienced periodic audio noise unless I turned WiFi off. I tried to use it briefly so I could set the clock by syncing with an NTP server, using my phone as a hotspot, but I couldn't type the password into the WiFi setup box so that also didn't work. (The onscreen keyboard only works inside the sBitx application, not for stuff in the OS.) Yet another reason to have a keyboard!

As expected, the rig only got slightly warm. I was sending at low power for only a small percentage of the time, as I was mostly searching for contacts rather than calling CQ. The upgrade to the switching regulator is necessary for some ops, and the reduction in receive power consumption is welcomed by all of us, but my sBitx worked fine for this use case without the mod.

Suggestions for future improvements: Add an AM reception mode. Improve the AGC action for CW. Add some additional features to the receiver, especially notch filtering and a noise blanker. Fix the issues with the keyer. Make the on-screen keyboard more useful by providing an easy way to type numbers and special characters. Add a way to set up macros without an external keyboard.??The A/B VFO control should relinquish the focus immediately after use; typically you tap it to switch VFOs, there is no reason for it to also hold onto the rotary encoder.The good news: ALL OF THESE can be implemented without changes to the hardware; that's the beauty of SDR.

The sBitx as it stands is already a good radio. But it can become an ever better one.