Quite a station there. I used to have the same problem with some bands on RTTY QRO. At the risk of giving someone advise who probably has more experience than me by far.
I'll repeat the obvious. Centralize RF grounding buss (where possible), everything connected in a star configuration to the RF grounding buss, not daisy-chained. Make sure the computer is grounded to the buss (this is key). Use wide strap for RF grounding; not wire. And of course, ferrite beads everywhere. And I will assume you RF ground system is all interconnected with flat copper strap. I had weird problems on all bands that were intermittent until I grounded the computer to the RF grounding buss. I would still get problems on 40M & 17M sometimes. This took considerably more detective work. I started adding ferrites one day until I found the main culprit. In my case, I had a resonant piece of CAT5 cable. Once I broke it up by putting a ferrite at the shack end and one at the router end, the problem was solved. This took some time of adding 1 ferrite at a time and transmitting RTTY on 40M at the minimum power level I knew caused a problem. 73, Scott AC8DE -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Phil Theis Sent: Monday, October 10, 2011 9:13 PM To: [email protected] Subject: [FlexEdge] High Power and a 5000A I have 22 bands integrated into my 5000A and am just getting around to working high power on the lower bands. Have 1500 watts from 160m - 70cm and good power beyond that in frequency. I worked the PA QSO party this weekend and although I had a little rf in my audio system (another issue that will be addressed) I had some significant issues when running cw. On SSB things seemed to be ok, but on CW I got some funny things happening on occasion with the mode window in PowerSDR. It seemed like it would momentarily switch into SSB mode. But that was so quick, I couldn't tell for sure. More disturbing was reports of sounding like having ac hum on the line. I had reports of need to check my power supply. I'm sure it's not the power supply as I am on a battery isolated by a Power gate product for keeping the battery charged. I have the usual rf choke installed on the Firewire line as well as an additional ferrite core around that cable. All devices are grounded well to a heavy ground that circles the house. Using an ACOM 2000a amplifier. The amplifier is located approx 20 feet away from the Flex near the antenna switching frame where antennas are switched. I added a DX Engineering Ferrite isolation choke to the input of the amplifier but it did not make a difference. I'm thinking next steps would be to start adding ferrite and coils to the coax feeding the amplifier to keep rf from coming back toward the Flex. I am looking for other folks experience and suggestions for next steps in being able to run full power on CW. Like I said, SSB seems to work fine. Thanks for input. 73, Phil K3TUF _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software. _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
