I did some work on SA818/SHARI-like devices this week. I started off with an AURSINC Shari device that, uhhh, a friend bought. But then Marshall KE6PCV was kind enough to send me two devices from the HotSpot Radio product line. Given how many hams I’ve encountered who are using AllStar with some form of SA818 radio it seemed like a worthwhile thing to experiment with.
I’m sure plenty of people have done product reviews of these devices so I don’t need to get into that. The two Hotspot Radio devices Marshall sent (HotSpotRadio USB and the USB Duplex Repeater) have a much better build quality than the AURSINK Shari and I’m sure the nice folks who operate on the 880 MHz band appreciate the 5th order harmonic filter on those boards. Unless I’m missing something the AURSICK device seems to jump right to the antenna connector. The noise floor is also lower on the HotSpot Radio devices from my rudimentary test.
I did some work to allow the SA818 serial programming to happen directly from my node configuration screen. Actually, the HotSpot Radio duplex repeater has two SA818 modules so I created the ability to save/load two independent radio configurations (see below). Having a duplex hotspot is really nice.
One thing I noticed about the SA818 is that there is a slight delay on key-down. From what I’ve read, this is a known problem with the module and is possibly related to power-saving modes. It’s not a huge deal, but it can cut off the very beginning of a transmission in certain cases. I did some work to address this which I’ll describe in a separate post about TX/RX delay. The SA818 firmware version was different between the AURSNIC and HotSpot Radio units but that didn’t seem to make much of a difference as far as key-down speed.
I needed to make a few other changes to my code to support these hot-spots, but overall they provide a decent way to get a radio link to AllStar. I’m no connoisseur, but the audio quality sounded fine to me.
