William Hein wrote: > The reported Flex-5000 2-kHz 105-dB IM3 figures are very impressive and would > land at #2 on W8JI's rx performance chart if tested by Tom and assuming the > figures hold: > > http://w8ji.com/receiver%20IM3%20sorted.htm > > A figure I don't see reported for the Flex-5000 is wide or narrow Blocking > Dynamic Range. According to the ON4UN Low-Band DXing book this ought to be > > 120-dB for serious low band DXing and contesting. W8JI reports 10-kHz BDR > numbers and the Sherwood tests rated several current hi-perf rigs > 130 dB > 100-kHz BDR with Orion at 137-dB and the IC-7800 at 135-dB. >
While I cannot say what the final official numbers are, the numbers were BETTER than 120 dB blocking dynamic range in the preliminary tests I did with Gerald. This was done with the usual method: put an out of band tone on and raise the level until the in band noise floor rises by 3 dB. These numbers need to be tested across various builds to make sure they are consistent across radios so do not take them as the final truth until Flex announces them. But the first results done a bit ago were very encouraging. Tom and Sherwood do not like A/D based receivers without analog AGC on the front end. Tom is correct in his determination that the blocking dynamic range on the SDR-1000 was less than it needed to be at 108-111 dB (as measured in the ARRL labs). Many believe this number is NOT as important to the average contester and certainly not to the average user. It is definitely important to the large station contester or SO2R contester. I agree with this. Unless you have a large transmit signal happening right next to you, you will find it hard to cause BDR to be the determining factor in your results. Now the Flex 5000 should be a fantastic SO2R radio with all of this multiple receiver and full duplex capabilities. If the BDR is in excess of 120 dB (and it is hard to see how it will not be), then "it has arrived" as an SO2R radio. The full duplex and two fully functional high end receivers in the 5000A or C (if you add the optional second receiver) will be a really great thing! Bob > http://www.sherweng.com/table.html > > Surprised that the SDR-1000 was never tested by Sherwood, hope the Flex-5000 > will make it to this lab. Most of the contesters/serious DXers I know > respect the Sherwood (and W8JI) tests and pay closer attention to these tests > than the ARRL lab reports which seem aimed at a more general ham audience. > > 73, > Bill NT1Y > > -- Robert W. McGwier, Ph.D. Center for Communications Research 805 Bunn Drive Princeton, NJ 08540 (609)-924-4600 (sig required by employer) _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
