For a description of the test set-up, click here.
As might be expected, each radio/software has advantages over the other. I like SmartSDR's (Flex) presentation and ability to zoom in on a signal (or pile-up) and see detail with great resolution. openHPSDR (Anan) can zoom in as well but visual resolution seems to become a bit grainy at some point, at least compared to SmartSDR. This may seem like a small detail but it is important in how I go about working a rare DX station on CW. I like to see the pile-up in as much detail as possible in order to determine exactly where to place my TX VFO.
And QSK - important enough to deserve its own paragraph - Flex has it; the Anan doesn't.
Flex's SmartSDR also allows easier selection of a second "slice" or VFO for operating split. Moving each VFO in relation to the other is more intuitive with the Flex - clicking and dragging on a slice or the background panadapter does what you would think it would do. On the Anan, there is a bit of a learning curve and the display behaves in one of several ways, depending on whether various buttons (CTUN, for example) are selected or not. To me, this is a minor point and either software platform will become second nature to anyone who uses it for a while.
I listened to the Baker Island DXpedition on both rigs simultaneously. I only ever copied them on 20, 40 and 80 meter CW. QRN on 40 and 80 was typical of June/July and the 14-bit Anan/openHPSDR combo kicks ass in the noise mitigation department. There are two easily selectable levels of Noise Blanking and Noise Reduction, each of which are configurable, and a few other controls to rescue a signal from various types of noise. I left mine at the default values and was really just amazed at the effectiveness of these functions. I was so taken with openHPSDR's ability to enable the little Anan lift a signal from such noisy conditions that it probably cost me Baker Island on 80 meters since I had a splitter in line and couldn't transmit.
I had no problem receiving KH1/KH7Z on 80m with the Flex/SmartSDR either but I really think openHPSDR has the edge here and I regret not making a comparative recording. Summer isn't over though, nor is the QRN it brings to the low bands - I'll put that on my To Do list.
Finally, I used FT8 to gauge each rig's ability to copy signals on 10, 15 and 20 meters. Screenshots are below but I'll shortcut it for you:
On 20 meters, both rigs seem about equal in their ability to copy signals. Decodes are always within a dB or two and no noticeable difference in signal strength would be possible on CW or phone.
On 10 and 15 meters, I turned on the Flex's pre-amp. Despite that, the decodes clearly show the Anan to be the better receiver. The screenshots below are just a brief sample of the comparisons I made but they are typical of other comparisons made on other days during different band conditions. On 10 and 15 meters (and probably 12m) the Anan hears better, sometimes decoding stations that are not decoded at all by the Flex.
None of the differences in dB values would be noticeable on non-digital modes. Only modes like FT8, WSPR and JT9/65 report the received signal level as part of the exchange and perform the calculations to obtain those values. On CW or phone, sensitivity differences in these two rigs would be impossible to discern.
During the next CW pile-up for a needed entity, which rig will I use? That's a tough question and I don't know the answer yet. Fortunately, I don't need to know because no needed entities are scheduled. But there are some pile-up generating DXpeditions coming up - Swaziland, Ducie, Mayotte and Rwanda to name a few - and I'll most likely be using the tiny Anan, if only to become more familiar with the software in those conditions.