[Hackrf-dev] hackrf with gqrx on low end of HF

[jed martin]

i was going to ask what i was doing wrong, but while waiting for subscription to this list to complete, i was playing with settings in gqrx, and kind of stumbled on the answer to my question...
i've been trying to use my hackrf to listen to the 80M ham band (as well as 160M and other assorted stuff in that part of the spectrum)  part of the problem i was having was that gqrx has a few "presets" for the hackrf sample rate, and with the default 
8Mhz sample rate, if i tuned the center frequency below 8Mhz, i just got a lot of hash from interaction of signals within the hackrf. so, i tried something not in the list of presets... setting the sample rate at 3Mhz, and setting the center frequency at something like 3.57Mhz (i tried a few different center frequencies and used the one that generated no hash).  then it was working within the 80M band, but something was still amiss, it was all backwards, the digital section was up around 4Mhz, and the phone section at the lower end, and LSB was USB....  while playing with the Input Controls settings, i clicked the Swap I/Q box, and it flipped everything back to where it should be...  it's a good thing i knew what i was looking for (i.e. what parts of the band are digital vs phone, and that 80M phone should be LSB) or i would still be befuddled...  i actually like the hackrf better than the sdrplay. it seems to have better s/n performance.  i think the sdrplay linux driver needs a bit of work, and when i recently upgraded the version of Skywave linux i'm using, the new sdrplay driver was really broken (which is the reason i tried the hackrf in place of it)
one question though... the 14db input amp has a limit of -5dbm?  that's about 200mV or so... i've been using it, but i need to keep all RF sources that can induce that much voltage into the antenna system far away from it, even if it's a cell phone and i'm using the radio on HF, correct?
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