Re: NDB - Airspy HF+ DIscovery versus Hermes Lite 2


Max
 

Before I made the videos I spent quite a while on the Airspy tweaking all settings of AGC, then AGC off and multiple different gain settings. The recording I showed was the best result I could get. With the HL2 I just plugged it in, started it and tweaked nothing. Actually there are almost no controls to tweak anyway. Just LNA which is adjusted to prevent overload as per the front panel LEDs. In fact I don't remember the last time I needed to change that. Then there is just Visual Gain, which I usually adjust for -125dBm with no antenna connected. Admittedly I forgot to make the visual gain adjustment on the Airspy so that probably explains the HF+ looking very noisy. The background noise level with this setup is actually about S3 as you can see from the HL2 recording. For the Airspy I set sampling bandwidth to the minimum of 192kHz to give it the best chance. With the HL2, although I made the recording with sampling bandwidth set to 48kHz it gave identical results on all sampling bandwidths up to it's maximum of 384 kHz. No difference whatsoever.

So here's the question. Which is the better receiver? The one which anyone can just attach antenna, turn on and it just works perfectly with no issue or the one we need to make multiple excuses for this that or the other not being adjusted correctly?  I know which I'd rather have. Anyway, I did not set out to pick any faults with the Airspy. Why would I? I just paid good money for it! Just thought an interesting comparison given that the Airspy is always hailed as the "best thing since sliced bread" as we say here in the UK. It's just I was therefore quite surprised that the HL2 easily bettered it on the first test. I am sure there are other areas where the Airspy will outshine the HL2.

As I said before, I'm very interested to see results on 17.2 kHz tomorrow.

For info, I do have a local quite powerful AM station (about 8 miles away) and this certainly causes severe issues with my SDR Play RSP2Pro and I can also see signs of it being an issue that needs careful tweaking with the Airspy too (nothing like as bad as the RSP though). But it does not cause any issues whatsoever with the HL2. For me at least on the first few tests the HL2 is just considerably better on the frequencies it covers. Of course no VHF FM (for example) on the HL2 so it's horses for courses as ever.

Max

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