Gerald,
As a wannabe Flex SDR-1000 owner, which will be soon I think, I am glad that you commented on this issue. I still need a little more push in my mind to finally decide. Will also keep the PROII and maybe the Omni 6+ too, at least for now. Thank you. 73 John, N3WT -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Gerald Youngblood Sent: Tuesday, August 29, 2006 7:55 PM To: 'Maarten N1DZ'; 'Radio Station W5AMI' Cc: [email protected] Subject: Re: [Flexradio] Sensitivity of SDR1K vs TS-850 on 10 Meters Marteen, I took a look at measurements of MDS on the TS-850 on the Sherwood Engineering site. He shows the MDS at -138 dBm with the preamp on and -128 dBm with it off. The SDR-1000 will be about -130 dBm with the preamp on high and -120 dBm on Medium. The SDR-1000 is optimized for highest two tone third order dynamic range at close spacing. In that regard the ARRL stated that stating that the SDR-1000's 99dB closely spaced third order dynamic range was, "about as good as we have seen." Sherwood shows the TS-850 close spacing IMD dynamic range to be 77 dB. That is a difference of 22 dB! There are always tradeoffs. The original preamp we shipped in 2004 had 15 dB more gain and sensitivity higher than the TS-850 at the expense of IMD dynamic range. Typically on HF, IMD dynamic range is more important than sensitivity. To see if yours is working properly. Calibrate the receiver with a signal generator. You can then connect a dummy load and measure MDS directly with the signal strength meter in average mode. You should get around -130 dBm in 500 Hz bandwidth below 30 MHz. If you want more sensitivity at the expense of dynamic range, you could convert the radio to the original SGA-4286 preamp. Oh, the dynamic range of the sound card will make a difference as well. I have seen as much as 5 dB improvement in dynamic range with better cards. 73, Gerald Gerald Youngblood, K5SDR FlexRadio Systems Ph: 512-535-5266 Fax: 512-233-5143 Email: [EMAIL PROTECTED] Web: www.flex-radio.com > -----Original Message----- > From: Maarten N1DZ [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 29, 2006 6:05 PM > To: Radio Station W5AMI; Gerald Youngblood > Cc: [email protected] > Subject: Re: [Flexradio] Sensitivity of SDR1K vs TS-850 on 10 Meters > > My TS850s has a much higher sensitivity in SSB on 10m than > the SDR1000. > On 6m the SDR1000 is plain deaf. > > 73 Maarten N1DZ > > On Tue, 29 Aug 2006 15:10:45 -0400, Radio Station W5AMI > <[EMAIL PROTECTED]> wrote: > > > We tested SSB (USB) and AM last night with the same > results, under the > > exact same test conditions, equipment, and obviously using > ground wave > > on 10 meters at 18.6 mile direct path. > > > > An occasional picket fencing would occur about every 30 minutes, > > however we avoided that condition for the tests. The SDR obtained > > more readability receiving on SSB over the other modes, however the > > TS-850 rcvr had the obvious advantage on all modes so far. The > > comparison tests were done within minutes of each other, and for > > several minutes at a time to avoid any kind of intermittent > anomalies > > in ground wave propagation. > > > > My point in all this is to determine if we might have a bad > front end > > on this particular SDR1K since the 850 is at least 16 or 17 > year old > > technology.... > > > > Tnx - Brian > > > > > > > > On 8/29/06, Radio Station W5AMI <[EMAIL PROTECTED]> wrote: > >> On 8/28/06, Gerald Youngblood <[EMAIL PROTECTED]> wrote: > >> > Make sure the AGC Max Gain is set to a high value if you > are using > >> v1.6.2 > >> > release. It is now called RF on the latest SVN version. > If this > >> > is > >> set > >> too > >> > low you will not get maximum sensitivity. On the SVN > version set > >> > it > >> all > >> the > >> > way to the right. Sensitivity should be around -130 dBm > in 500 Hz > >> with > >> the > >> > preamp set to high. > >> > 73, > >> > Gerald > >> > >> AGC does not have any effect in FM, at least on my console > - SVN 654. > >> Is there something maybe I'm doing wrong? > >> > > > > > > > > -- > Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ > > _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
