RF feedback was just one of a number of problems I encountered when setting up my Flex 5000. It turned out the RF was getting from the radio into the computer by way of the FireWire cable. Someone recommended that I purchase a cable from Granite Digital which I did and it completely cured the problem. The cable is expensive but it had double insulation and gold contact pins as well as ferrite cubes on both ends. Apparently, the FireWire cable supplied by Flex does not always work very well in some installations. One of the other issues which for a while masqueraded as an RF problem turned out to be caused by the fact that I had one buffer size set in the driver and a different buffer size in Power SDR. That is a no-no. After I corrected both issues I have had absolutely no problems with RF or RF like symptoms.
Bruce-W8FU On Feb 19, 2010, at 5:17 PM, O. Johns wrote: > One problem with radios like the Flex hasn't been mentioned much. It is the > RF feedback problem. I have seen demos of the Flex in action, and > practically every cable in sight had to be loaded down with chokes to keep > the RF out of the transceiver control circuits. > > On the face of it, the P3 in its small metal box adjacent to the K3 should be > better isolated against RF feedback. I sure hope Elecraft is checking this > aspect closely. There are interconnects between K3 and P3. Are they > vulnerable? > > 73, > > Oliver > W6ODJ > > > On 19 Feb 2010, at 1:46 PM, Jack Smith wrote: > >> The graphics processor makes a big difference. I have several Dell >> SX-260 computers that run SDR programs painfully slow, despite 2 GB of >> RAM and 2.5 GHz CPU. >> >> It turns out that Dell's graphic processor has no dedicated memory but >> rather shares normal RAM. That creates a huge bottleneck when running a >> graphics intensive program such as all the SDR software. Some is >> slightly worse than other but they all bog way down on the SX-260 >> compared with a machine with a separate graphics card and memory. Same >> SDR program on the SX-260 may run 70% CPU but only 10% on a computer >> with a separate graphics card and memory, with similar CPU speed and RAM. >> >> Jack K8ZOA >> >> >> On 2/19/2010 4:18 PM, ab2tc wrote: >>> I would have agreed if Windows had offered developers an easy way of >>> prioritizing threads and processes. But as far as I know it doesn't (or >>> developers don't know how to use it). In my experience the performance of a >>> PC with 90% CPU load is miserable for all processes running on it. With that >>> said, I don't see why PowerSDR should incur that kind of CPU load on a 3GHz >>> machine. I am running XP home edition on a dual core Dell at 2.9GHz and 2Gb >>> of RAM. My CPU utilization is hovering between 15 and 30% with all of the >>> following running: >>> >>> LP-Bridge >>> HRD >>> PowerSDR with EMU-0202 sound card at 192ks/s >>> VE7CC cluster client (highly recommended) >>> Iexplore composing this message >>> Thunderbird mail client >>> DX Atlas >>> >>> I can add more applications and the CPU barely nudges upwards. I think most >>> people would agree that a car that has to be driven always with the >>> accelerator nearly to the metal is underpowered and not much of a joy. I am >>> a firmware developer and we always worry whenever the CPU utilization >>> exceeds 50% even though we use OS's that allow intelligent prioritization of >>> tasks. >>> >>> AB2TC - Knut >>> >>> >>> Al Lorona wrote: >>> >>>> Just a minor point: There might be a misconception that high CPU >>>> utilization means your computer is inadequate for the task. >>>> >>>> Actually, you want the CPU to work hard for you. It isn't only CPU you >>>> should worry about, it's what is called the 'run queue'. The run queue >>>> determines how long your job has to wait until it's serviced by the >>>> computer. It's okay to have 100% CPU (and in fact you want it) if you >>>> don't have to wait at all. >>>> >>>> A person assessing the performance of a computer looks at several other >>>> things besides CPU when determining what to tune for better performance. >>>> >>>> >>>> Don Wilhelm-4 wrote: >>>> >>>>> >>>> >>>> >>>>> I am using a 3.0 GHz Pentium 4 with 1 GB of RAM, running >>>>> WinXP Pro and the CPU utilization ranges from 50% to 90%, so anyone >>>>> thinking of choosing this alternative with a lesser computer had better >>>>> think about a new computer first. >>>>> >>>> <snip> >>>> >>>> >>>> >>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
