The overload may not be the "fault" of the SDR-1000 setup at all. Having worried with cross-station interference at multi-transmitter contesting stations for 40+ years, just about anything can be driving even the best of devices to fits.
A small list, hardly complete, that I have encountered, a rig having fits because... High levels of RF on one AC socket, not on another, because of how the AC wiring is run to the breaker box, or because it is run to a different breaker box. Broken or absent ground on one rig vs. another. The station having fits can be either the one WITH the ground or without it. Shield connection with even a tiny amount of diodic action due to poor connection. Broken shield on a coax connector, anywhere in the shack and not necessarily in use by the station having fits. An unfortunate long length and placement of coax (even with "grounded" shields) that places a common mode voltage max near the rig having fits. Not necessarily connected to the rig having fits. High levels of RF on the 120 safety ground or 240 neutral that somehow are satisfied by running to one or more feedline shields. Use of "wall wart" power cubes to run anything, that's anything, in the shack. Some critical mass of numbers of cables in the shack. All the case screws on something weren't tight. Case not connected to chassis due to paint or ... --- Some of the above are improved by having a single point ground, but if the ground is generally poor, it may not help. Some troubles disappeared mysteriously apparently just because a few of the cables in the rat's maze were moved, removed, etc, leaving us without any real explanation for the problem. With all the above as a caveat, I would be surprised if the engineers that designed the FA-66 ever tested it in a high RF environment. It's an AUDIO box, right? (Those hams are doing WHAT with it?) 73, Guy. ----- Original Message ----- From: "Mark Amos" <[EMAIL PROTECTED]> To: <flexradio@flex-radio.biz> Sent: Thursday, February 01, 2007 4:53 PM Subject: [Flexradio] Contesting question > All, > I visited a contesting station this past weekend for the 160 > contest. I took the SDR-1000 and subsidiary equipment with me - not > to operate, just to see how it might work in a future contest. Also, > I wanted to show it to the op that was working the contest to show > him the quality of the receiver. > The station was out in the country and had acres of antennae to play > with. I hooked into a receiving dipole - situated about a half a > mile from the transmitting vertical and broadside to it to avoid as > much vertical groundwave as possible. When the contesting station > wasn't transmitting, the performance of the Flex was very good. > Also, out there in the country it was very quiet - I was able to > copy signals down below S1. My station is normally in the city and > my noise floor is usually S5 on 160. > The primary station was two late model FT1000s with some custom > modifications. One was the primary CQ rig and the other for S&P. > Typically, the S&P rig worked great anywhere out past 1K or so from > the CQ frequency. > The Flex-Radio, on the other hand, was pretty much unuseable when > the transmitter & amp were running. It saw every dit from that > transmitter out to dozens of KHz's away - spurs popping up and > drowning out even S9+ stations. > I've never operated in a high RF environment before, so maybe its > just the way it is... The station itself was several hundred feet > from the transmitting antenna. The transmitter was running > significant power. > I was just surprised at the difference in useability between the > FT1000 receiver and the Flex Radio - the FT1000 was clearly useable > in this situation and the Flex was clearly not. > The soundbox was an Edirol 66, I had ferrite filters on all the > cables connecting computer, Edirol, radio, power supply, etc. I used > a multi outlet power box with some filtering in it (a heavy-duty > computer isolation outlet box.) I used the current SVN build > (whatever was current as of a week ago.) > I should say that the SDR-1000 was set up rather quickly and was > probably not adequately grounded. Also, I didn't do the calibration > until late in the contest, but it didn't seem to help a whole lot. I > did notice a slight reduction in the transmitter interference / > noise when I turned the Preamp to Off, but I think it was still > unuseable. > Just looking for experience of other folks that might use a Flex in > proximity to a high power transmitter. Any thoughts as to what I was > doing wrong, or was I just expecting too much? > Mark > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070201/e955bda3/attachment.html > -------------- next part -------------- > An embedded message was scrubbed... > From: "Tim Ellison" <[EMAIL PROTECTED]> > Subject: Re: [Flexradio] Dumb newbie question -- but please read > Date: Thu, 1 Feb 2007 21:11:00 +0000 > Size: 7279 > Url: > http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070201/e955bda3/attachment.mht > _______________________________________________ > 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 Homepage: http://www.flex-radio.com/ > > FlexRadio Knowledge Base: http://kb.flex-radio.com/ > Scanned for viruses by Blue Coat http://www.WinProxy.com/ _______________________________________________ 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 Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
