Dear Don, Just did check the dummyload with an MFJ analyzer and is working fine on 160m and higher.
73 Koert PA1KW Koert Wilmink wrote: > Dear Don, > > Thanks for your support!! there is a deep and sharp null for all bands > except 80 &160m, cannot get lower than 1.3 for 80 and 1.8 for 160, I did > check the core and it is the large dark gray core. I also removed T4 and > did check the solder connections. No difference in results. > Maybe asking Elecraft for a new FT50-43 core? I also will ask my > colleague amateurs for another dummyload, just to be 100% sure. The > current one I'm using is from Annecke and the freq it is capable of > handling is 2 Ghz. > 73 Koert PA1KW > > > Don Wilhelm wrote: > >> Koert, >> >> The absolute minimum voltage found in the C1 null (as observed at TP4) >> is not as important as the depth of the null. >> >> If you cannot achieve a deep and rather sharp null, there is something >> wrong with either T4 and its associated components or with your dummy >> load. The actual voltage at the null will depend on the power level >> used. >> >> Assuming your dummy load is good (you can check it with an antenna >> analyzer), you should see a 1.0:1 SWR on all bands. >> >> Since you indicate a higher SWR on the low frequency bands, that >> suggests that T4 does not have adequate inductance for those bands. >> Check that you have used the correct core for T4 - it should be one of >> the gray (ferrite) cores and not one of the black (powdered iron) >> cores. Be certain that T4 has well stripped leads and is properly >> soldered. If you observe toroid solder connections that look a bit >> like volcanos, that lead was not well stripped - a good solder >> connection will look like a mountain with concave sides - if it has a >> convex shape, too much solder was applied and that fact can mask a >> poor solder connection - wick away the excess solder and resolder >> properly. >> >> 73, >> Don W3FPR >> >> Koert Wilmink wrote: >> >>> Dear all, >>> >>> Please find my emails to Elecraft support below. Is there maybe >>> somebody with additional tips? >>> >>> Thanks!! >>> >>> 73 Koert PA1KW >>> >>> >>> >>> ----------------------------------------------------- >>> Hi Gary, >>> >>> Sorry for my late response, but I had not the opportunity to work on >>> this earlier. I moved houses and that took longer than expected. >>> >>> I did check the HV bias and that is 135volts. The diodes are ok and the >>> voltage on TP4 2mV on receive and 240mv on transmit (tune). >>> I did connect a good dummyload close to the KPA100. >>> I did the re-adjustment of the SWR bridge but this provided me not the >>> required results. The best results with adjusting C1 on 5 Watts is: >>> >>> 160m 1.8-1 >>> 80m 1.3-1 >>> 40m 1.0-1 >>> 30m 1.0-1 >>> 20m 1.0-1 >>> 18m 1.0-1 >>> 15m 1.0-1 >>> 12m 1.0-1 >>> 10m 1.0-1 >>> >>> Please help...... >>> >>> Best regards and 73, >>> >>> Koert Wilmink >>> PA1KW >>> >>> >>> > _______________________________________________ > 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 > > _______________________________________________ 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
