Frank N. Haas KB4T
Tue, 16 Feb 2010 15:10:55 -0800
Most of what I have written about the resolution of my Intermittent NO POWER OUTPUT problem has been WRONG. Utterly wrong. If I could I would NUKE every message I have posted to this thread except the first which alerted the group to my issue.
The Executive Summary: RF Intrusion was locking up my Flex 5000a system. While operating on 40 meter SSB at legal limit output power, I would key the transmitter and it would transition to transmit but not make any watts. Occasionally the Flex radio system would lock up so badly I could only power down the hardware box by pulling the power plug on the back panel. My full wave 80 meter horizontal loop antenna at 30 feet is fed with windowed ladder line. The windowed ladder line runs into the shack to my balanced L tuner. I run legal limit most of the time. Despite the fact that this configuration has worked flawlessly for years with all previous rigs, the Flex is more sensitive to RF in the shack. Reducing the amount of RF in the shack solved my problem. I trimmed the length of my windowed feedline to reduce the amount of RF in the shack as indicated on a field strength meter. Now I can run legal limit and all the programs I want simultaneously without suffering the intermittent no power out problem. I typically run PowerSDR, Ham Radio Deluxe, Firefox, my email client and other programs all at the same time on an Intel motherboard-based clone using a Duo Core 2.4 GHZ processor, 2 GB RAM running Windows XP Home with an average of 100 us DPCs. I want to thank Tim Ellison W4TME and Dudley Hurry WA5QPZ for their informative assistance and patience as I slogged through the step-by-step process of narrowing down the true source of my problem. Troubleshooting Journey Initially I assumed that since all previous radio equipment had functioned in my shack for years without any RF intrusion issues, the Flex should have as well. Thus I discounted the possibility that RF intrusion was the cause. I concentrated on all the other possibilities first. Because of the symptoms I observed, I zeroed in on the computer and software. Shaving back memory usage by the operating system proved useful but it didn't solve the problem. Even if I ran only PowerSDR alone, the NO POWER OUTPUT problem would persist albeit somewhat less often. I applied lots of ferrites to various cables with only limited success. I would still suffer NO POWER OUTPUT and occasionally the Flex Radio box would lock up so badly I had to pull the power plug on the rear panel to reset it. I upgraded my Firewire cable to a Granite Digital triple shielded version. That did not solve the problem. I verified that all grounds and bonds were solid. The computer and the Flex Radio are connected to the same ground with short wide leads. The ground system consists of ground rods outdoors connected via fairly short wide conductors through the wall directly to the single point ground in the shack. I checked DPCs and found the numbers well within acceptable bounds. I verified that I was running the latest versions of PowerSDR, Flex Radio Firewire Driver and the Flex 5000 firmware. I even uninstalled everything and re-installed. None of this fixed the problem. I reset the database twice. No joy. Verified the PA BIAS was set correctly. It was. I was running out of possibilities. RF intrusion was the last item on the list. If I didn't run the amp, I never seemed to experience the problem. Fire up the amp and the problem was fairly consistent. That was a pretty clear sign that I should have seen earlier in the process. Trimming the length of the windowed ladder line was the only step I could take to reduce the amount of RF in the shack. I chose a length that didn't resonate or match a half or quarter wavelength on 80, 40 or 20 meters. After several days of trouble-free operation, I'm ready to claim victory. Dudley suggests that the Flex Radio System is more sensitive to RF because the RF section and the IF/Audio section are essentially 2 separate boxes connected by a 6 foot cable. That's a configuration unlike any conventional ham rig and it does increase exposure to the vagaries of RF intrusion. I am the poster boy for that fact now!!! Running legal limit demands that you insure everything is built right and tweaked for minimal RF intrusion if only to keep your lips from being bitten at the mike or fingers getting zapped at the key. This is especially true for those of us who use open wire feeders to enjoy multi-band operation with a single wire antenna. The Flex Radio System requires EVEN MORE CARE in this regard. I'm not suggesting this is a bad thing. After all, proper station layout, cable dress, grounding and neatness are worthy objectives to which all station operators should strive. When experiencing peculiar behavior with the Flex Radio System, RF intrusion should probably be the first thing considered rather than the last. We tend to blame the software or the computer first. Experience has clearly shown me that software and the computer are the last items to worry about. Take 2 steps back and study the shack "environment." Consider the sensitivities of the "system." Ask yourself, "What do I see that might contribute to RF getting into the "system?" Your dummy load is your best friend. If things work well when transmitting (even at legal limit) into the dummy load, forget about the software or the computer. It's likely you have some housekeeping to do especially if you like to use parallel wire feeders. Much has been written about DPCs (Delayed Procedure Calls) and their impact on the operation of the system. I agree that checking DPCs using either the DPC Latency Checker in the Flex Radio Driver program or the DPCLAT.exe by Thesycon.de is a good thing to do. Others, more experienced and knowledgeable than I, have clearly stated that DPCs can have an impact but only when DPC numbers tend to be fairly high. I checked DPCs as part of my troubleshooting adventure but the numbers always averaged well below 150 us. In the 4 months since I became a Flexer, software has never been a problem and changes to the software or computer have never been a solution. Sources EXTERNAL to the Flex Radio System have been responsible for all of my problems. Everyone's computing environment is different so your mileage may vary in this regard. If it's possible to DELETE all previous emails I've posted to this thread except for the first one I wrote, I hereby authorize that action.if only to prevent the torture of future readers who would otherwise have to slog through several useless messages to reach this one. I freely admit that my station configuration likely pushes the envelope for the Flex Radio System. If I can successfully overcome the issues I've had, ANYONE can do so. If the Flex system can be made to work in my environment it should work anywhere PROVIDED steps are taken to address the sensitivities of the system. I encourage anyone experiencing peculiar behaviors in their Flex Radio system to give greater consideration to the possibility of RF intrusion first before blaming the software or computer. RF intrusion can cause very strange problems that could easily be considered software or computer-based. Use your dummy load and a sensible step-by-step troubleshooting procedure to pinpoint the cause before assuming the failure lies within the (fairly stable) software or computer. Most importantly, keep an open mind. ASSUME NOTHING. Good luck. 73, Frank N. Haas KB4T Florida _______________________________________________ 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/