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


jdow
 

Likely that would be antenna impedance variation and over exuberance for the matching transformer.

{^_^}

On 20211227 09:20:58, Max wrote:
On Mon, Dec 27, 2021 at 10:28 AM, Max wrote:
On Sun, Dec 26, 2021 at 03:24 PM, sm6fhz wrote:
If you missed the SAQ transmission on December 24th you have a new opportunity on December 27th
Thanks Ingolf. Only just seen this so listening.

Eventually heard SAQ this morning. Two video recordings linked for anyone who is at all interested. First one shows "VVV de SAQ" test signal from SAQ. Second one they were presumably trying to optimise antennas as it's just carrier (note the alternator drift!).

For those that wanted to see (Simon), ribbon bar in second video shows the HF+ settings. For Joanne I made sure to engage AGC as requested. Tried both settings (see second video), and also you will see preamp on and preamp off. Not much change. Antenna 66ft end fed wire, so far from ideal at this frequency. With a well matched antenna I'm sure results would have been far better.

Videos:

SAQ "VVV test"

SAQ Carrier

As per 24th compared with HL2 and RSP2Pro. Results exactly the same. Zero on HL2 (as predicted - below published frequency spec for unmodified unit) and on RSP2Pro, audible but not really readable (with juggled settings).

Yes, as per comments, both for 24th and today, antenna always connected direct, no splitter (I have not got one).

So again in this test 17.2 kHz the Airspy triumphed but at 277 kHz CHT NDB I've gone back and retested and consistently and possibly surprisingly the Hermes Lite is the winner over the HF+ by quite a margin. Next I need to test with better optimised LF antenna (loop?) and see if the disparity still exists. I still really like the tiny Airspy, and of course I adore my HL2. Both brilliant bits of kit for very little money. We are very lucky people to have such hardware available to us and of course goes without saying would not be possible without the likes of Simon's superb SDR Console. There's none better!

Max

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