Thursday, March 19, 2009

NR audio files

I had a few minutes to record a mp3 of some 75M audio

The audio starts at normal 2.7khz filter NR is added then RX-EQ and the audio is tailored with the EQ in the 10 band mode. I switch the NR in and out. When its noisy NR is out. Bin is turned on and it makes a difference in the headphones, but the BIN output does not translate well to the mp3. Its effect is much more dramatic in my brain.

The band is filled with static, s-6 to s-7 with crashes to s-9 +5 and the station is s-7.

75m NR

This clip is of just noise in a clear spot on the band. The s meter is the same with NR in or out

75m Noise

On 40m this morning I was watching the S meter while I switched the filters.

The narrowest filter the radio allows is 11hz and at 11hz I was getting about -128 to -130dBm band noise. At 25 I got -128 to -127 dBm At 50 I got -127 to -125 dBm and at 100hz I got -124 to -122 dBm.

JT1R came up on the Cluster and I switched to 80M. With the filter set at 11 or 25 I could hear him out of the noise. Not good enough to copy. I would get JT or 1 or some part of the callsign, but I could hear a coherent signal bobbing out of the noise. At 100hz there was nothing.

MDS on 80 at 11hz is -120dBm and at 100hz is -114dBm 6dB makes a difference!