Drake TR-7 Noise Blanker (NB-7). And, it's excellent performance without distorting received audio.

Short Video showing Drake TR-7 Noise Blanker (NB-7) in operation. And, it's excellent performance without effecting the received audio, etc.
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Early springtime, in the evening, on 80m, in south Florida.
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Natural background noise level here was approx. S-4 to S-4.5, with local/regional lightning-static-crashes to S-8 and S-9 (actually not bad, as summertime they can be +20 to +30dB over S-9).
[note: AGC was set to "fast"]
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Beginning of the video the Noise Blanker is On / active....then at approx 3 seconds in, the Noise Blanker is switched Off to show the local RFI for approx 4 seconds.....and then, at approx 7 seconds in, the Noise Blanker is switched back On for the remaining 4 seconds.
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The S-8 to S-9 of local RFI (from florescent lights) is the buzzing noise you hear, and see on the S-meter, during that approx 4 seconds in the middle of the video....
This is just to show the excellent operation of the old venerable (1970's technology) Drake TR-7 and its Noise Blanker (NB-7, which was a ~ $85 option....which in today's dollars would be approx $400!! for just the Noise Blanker!)
The Drake TR-7's Noise Blanker is known worldwide as one of the best (if not THE best) of all HF receiver noise blankers, ever. (But, it's not just the Noise Blanker itself, it is the overall design of the TR-7 that allows this blanker to work so well and not effect/distort the received signals!)
Although, I'm currently only on 80m here, in the past when on 20m with low noise levels of S-0 to S-1, I've seen the NB-7 noise blanker take an S-9+ powerline noise down to S-1 or below! and still have no adverse effect on receive signals!
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See www.qrz.com/db...