Monday, September 22, 2014


There is the usual controversy over on EHAM regarding the noise blanker performance especially in the Flex 6xxx series.  Since I own both a Anan100D and a Flex 6300 I thought I might publish a picture of the 2 noise blankers in action

(click the pic for increased resolution)

My friend Steve K5FR of DDUTIL fame added a digital readout of the Flex 6300 S meter.  I prefer this to the S meter readout for this kind of discussion since the readings are exact.  The readings on the 6300 are -98 dBm reducing to -117 dBm or a 19 dBm improvement in the noise floor.  In the Anan 100D we see a -20 dBm improvement, -89 to -109 dBm.  A virtual dead tie which is well within the margin between the two radios.  Both radios show a greater than 3 S unit improvement average, 4 S units on peaks.  I tried both noise blankers on the Anan but didn't see a numeric difference between the two.  This data is of NB 1 which is my normal choice.  

This test was performed a 14:30 local on 30M using the same antenna, a full sized 80M 1/4 wave vertical tuned to the 30M band with a MFJ 998 tuner.   Both radios are on CW with a 450hz offset and 100 Hz filters.  No other noise abatement is employed.  The dummy load (no antenna terminated in a high quality shielded 50 ohms) noise floor on the 6300 is -130 dBm and on the Anan 100D, -117 dBm.

FWIW here is a pic of the lightning map in my area at 14:30

I'm on the east central coast of Florida right under that big yellow/red blob of lightning.  I am running the latest alpha version of SSDR and the latest general release of HPSDR/firmware.  Personally I can't kick about being able to receive S0 to S1 signals in the middle of a huge thunder storm.  I present the data unvarnished so you can draw your own conclusions.

73   W9OY