Hi Dave, The spur on my 5000 is not as low as the one in the review 5000. Mine is about 58 dB down.
Yes, I am referring to CW. While I have the floor (again) let me just mention to everyone that the initial thread on the Top Band reflector that started this discussion actually began by noting some great features of the 5000 receiver & PowerSDR software that provide the capability to conduct accurate noise floor and signal comparisons very nicely thanks to the calibrated dBm scale of the Panadapter and the peak feature. For those of you that caught my presentation at the SDR Forum at Dayton this year you will recall this as one of the many great features I noted about the 5000. In addition, if you have read the W5ZN & N4HY paper on the 8 Circle Vertical Array for Low Band Receiving (www.w5zn.org) all of the noise floor and signal comparison tables and data were compiled using the 5000 receiver & PowerSDR. That capability is a must for anyone evaluating the noise at their QTH or for antenna comparison. Forget an S meter on a conventional radio! So, you actually get a nice piece of "test equipment" by virtue of this "built-in" feature. Just wanted to make sure it is clear that I am NOT anti-Flex and there are a number of great features of the 5000 that I have publicly presented via other forums that some of you may not be aware of. So please don't take this one issue (that I know Gerald & Company want to resolve) out of context! 73 Joel W5ZN -----Original Message----- From: David Beumer W0DHB [mailto:d...@w0dhb.net] Sent: Tuesday, October 20, 2009 7:11 PM To: w...@arrl.org Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] Flex 5000 Transmit Spur Joel Thanks for the clarification .. I did see the spur on the ARRL review spectrum display about 70 db down. The DX'ing and contesting you refer to is CW , correct ? Dave W0DHB Joel Harrison wrote: > > Greetings Ian and all, > > Yes that was my post and YES, the spur DOES exist with the 5000. I > cannot speak to the 3000 as I have no experience with it. > > Allow me to tell you my actual, documented on the air experience with > this issue. First, if you look at the ARRL product review you can see > the spur on the spectral display about 2.4 KHz below the fundamental. > It is way down from the fundamental and during normal, rag chew "how > great is my audio" 100 watt operation it will most likely never be noticed. > > Now, enter an arena on 160 meters working DX where you will run an > amplifier, sometimes a gain antenna and most likely be using low noise > receive antennas (I run 1.5 KW and Beverages & vertical array rx > antennas as most DX'ers do on 160). Early one morning, a DX station > was listening up 2-3 KHz. I was up about 2.5 KHz calling and was > slammed on the air and on the 160 meter chat reflector for calling > right on the DX stations frequency. Of course, this wasn't the case > however I investigated and discovered that the spur does in fact exist > and under many conditions WILL be heard by other stations. This is a > hardware related spur with the 5000 and not with the PowerSDR software. > > W5UN (who was aware of it as well), W5LUA and I ran tests to try to > resolve the issue but were unsuccessful. The spur was clearly present > and could be heard in all tests. Flex was notified but frankly, with > all due respect to the folks at Flex, it took a bit of explaining and > help from N4HY to make them understand why this was an issue. The 160 > meter contest was coming up and I dearly wanted to use the 5000, > however attempting to use it with the spur issue would have been > suicide for W5ZN. My buddy Bob McGwier, N4HY, jumped in and wrote a > manual software routine that generated another spur in software that > you adjusted to the same amplitude as the offending hardware spur, > then you moved the software spur onto the hardware spur and adjusted > the phase of the software spur to greatly reduce the hardware spur. > This procedure works, HOWEVER, this procedure is ONLY good for one band at a time and if you change bands you have to run the manual procedure again. > > A few weeks ago I was on 30 meters calling a DX station...same > situation, up about 2.5 KHz and I got slammed again. I had not run the > manual spur reduction procedure because it is cumbersome, I change > bands a lot, so I got nailed. > > Those are the facts. Flex has known about this for about one year now > and nothing has been done to address it other than Bob's software > procedure (which I greatly appreciated him doing!). In fairness to > Flex this probably only effects less than 5% of their customers so > there is no real urgency on their part to address this. If you're > going to enter the DX and contest arena, though, please beware and the reason for my TopBand reflector post. > In time, you will get nailed to the wall with a nail gun because of it! > > Sadly, as a result of this, I no longer use my 5000 on HF. The > receiver is great and performs very well, however the xmit problem is > something I cannot accept at W5ZN in my DX and contest operation. > > I mean no offense by this email whatsoever to Flex or anyone, these > are simply the facts of my on-the-air experience and any effort to > permanently resolve this will be most welcome. I would like to use my 5000 on HF again. > > 73 Joel W5ZN > > > > Date: Mon, 19 Oct 2009 20:38:40 +0100 > From: Ian Wade G3NRW <g3...@yahoo.co.uk> > Subject: [Flexradio] Flex 5000 transmit spur > To: flexradio@flex-radio.biz > Message-ID: <6xkbu9nabm3kf...@ntlworld.com> > Content-Type: text/plain;charset=us-ascii;format=flowed > > I just came across this contribution from Joel, W5ZN, in the top band > contesting list, and was surprised to read the second paragraph > ("Also, be aware ..."). > > As a prospective Flex 3000 purchaser, should I be concerned? > > ------- Forwarded message follows ------- > Subject: Topband: noise floor > Newsgroups: !topband > To: 'Pete Parisetti' <hb9...@gmail.com>, topb...@contesting.com > From: Joel Harrison <w...@arrl.org> > Reply-To: w...@arrl.org > Date: Sun, 18 Oct 2009 21:35:06 -0500 > Message-ID: <80c27fa30e524e5796108d76c2458...@wgint.net> > > Pete - one other thing I need to mention if you haven't noticed > already....The noise floor will be different with each of the three > sampling rates (48, 96, 192). This doesn't change the signal to noise > ratio will change the display. The lower the sampling rate the lower the noise floor. > > Also, be aware that the Flex 5000 has a transmit spur approximately > 2.4 KHz down from the fundamental freq. If you are calling a station > up 2 KHz or so and are running an amplifier you will most definitely > put out a signal, thanks to the spur, that people can hear. Flex is > very aware of this but they have NOT, repeat NOT fixed this. One of > their software gurus did write a MANUAL software routine in PowerSDR > to address this hardware issue and it does reduce the spur > significantly but the procedure is a manual procedure and is only > effective on one band at a time. If you change bands, you have to run the manual routine again. It is cumbersome. > > After being "busted" twice on two different bands because of this I no > longer run my Flex 5000 on HF for transmitting. It has a very good > receiver and the calibrated dBm scale is great to use for signal > comparison and love it for that, but just be aware of the xmit spur. > > I can give you more specific details if desire. > > 73 Joel W5ZN > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ Message delivered to arch...@mail-archive.com
