Hi Rich, Have you tried disconnecting the antenna system and putting a 50 ohm dummy load at the output of the Daiwa ? If the Daiwa is OK and the tuner's VSWR bridge is OK both should give you almost the same readings. I say almost because the additional connectors and line plus the Daiwa that the tuner sees between it and the dummy load will make the tuner's load something other than 50 ohms, unless something in the Daiwa - 16" line combo is compensating. But the diff should be small, increasing with frequency - but still small.
If that's OK and you reconnect the antenna system and the problem comes back, then either the antenna system does not look like 50 ohms resistive at the "problem frequencies" or you have "antenna currents" on the outside of the feeder - or both - or some grounding problem. If of any help I would be glad to discuss symptoms / possible cures off list. When I did the null adjustment with C31 I also found the null to be shallow and quite broad. But after moving the one wire primary of T1 so that it passed through the core dead centre, the null became much deeper and sharper. KAT100 now gives reasonably correct readings. Good luck es 73, Geoff GM4ESD ----- Original Message ----- From: "Rich McCabe" <[EMAIL PROTECTED]> To: "Elecraft Reflector" <[email protected]> Sent: Friday, September 24, 2004 4:31 AM Subject: [Elecraft] Cal AT100 SWR bridge > Is there any tricks (or improved techniques) on adjusting the SWR bridge in > the tuner? I just finished a tuner and everything checked out and calibrated > very easy. But I may have a SWR that agrees on my Daiwa in the line 16" away > or it may be as high as 4:1 on some bands even when the tuner says it is > flat or near flat. > > I have adjusted C31 for minimum reading (.01 volts) and the null is small so > I really cant center it in the null easily. > > I also had a problem with oscillations on 40 meters and I think I read > somewhere it could be a grounding issue. So I am going to go back and do > some more sanding. > > Any tips or comments. > > Thanks, > > Rich > _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
