BL2 Balun Heating
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Just passing along some information that might be of interest.
I have the K3 with the auto tuner built in. My antenna is a Cobra Ultralite fed with ladder line. I can switch between a Johnson Matchbox and a BL2 balun/KAT3 to feed the antenna. I previously had adjusted the feedline length so that the Matchbox would find a 1 to 1 match on all bands 80 through 10 including 30, 17, and 12 meters. I have received many good signal reports on all bands with either matching system. I brought home an Omega temperature monitor and put the thermocouple inside the core of my BL-2 balun (set to a 4 to 1 ratio). I just had a 30 minute QSO on 20 meters with the K3 set to 100 watts. The balun temperature started out at 74 degrees. By the time the QSO had ended, the temperature was up to 120 degrees, a 46 degree increase. The same kind of thing happened on 40 meters. I have not yet tried another band. Signal strengths on both ends were 569 to 579. I once did an A/B comparison at 10W on several bands with the KAT2/BL2 vs. the Johnson Matchbox and there was no real difference on the other end. That was very subjective, though. The balun loss may or may not be that noticable on the other end. Happy 4th of July. 73, John W2XS |
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In reply to this post by John W2XS
>Just passing along some information that might be of interest. > >I have the K3 with the auto tuner built in. My antenna is a Cobra Ultralite >fed with ladder line. I can switch between a Johnson Matchbox and a BL2 >balun/KAT3 to feed the antenna. I previously had adjusted the feedline >length so that the Matchbox would find a 1 to 1 match on all bands 80 >through 10 including 30, 17, and 12 meters. I have received many good signal >reports on all bands with either matching system. > ><snip> > >Happy 4th of July. > >73, > >John W2XS I have the same antenna, the Cobra Ultralite with window line, and simply connect the two ends of the window line to an SGC-230 automatic tuner http://www.sgcworld.com/230ProductPage.html which is mounted outside. I have the tune power of the K3 set to 3 Watts. No balun required. Works great, 80 through 10. Paul N4LCD _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by John W2XS
My doublet ladder line feeds straight into the K3 without external tuner. Why use another box?
David G3UNA > > From: [hidden email] > Date: 2008/07/09 Wed PM 09:12:34 BST > To: [hidden email] > Subject: Re: [Elecraft] BL2 Balun Heating > > > >Just passing along some information that might be of interest. > > > >I have the K3 with the auto tuner built in. My antenna is a Cobra Ultralite > >fed with ladder line. I can switch between a Johnson Matchbox and a BL2 > >balun/KAT3 to feed the antenna. I previously had adjusted the feedline > >length so that the Matchbox would find a 1 to 1 match on all bands 80 > >through 10 including 30, 17, and 12 meters. I have received many good signal > >reports on all bands with either matching system. > > > ><snip> > > > >Happy 4th of July. > > > >73, > > > >John W2XS > > I have the same antenna, the Cobra Ultralite with window line, and > simply connect the two ends of the window line to an SGC-230 > automatic tuner http://www.sgcworld.com/230ProductPage.html which is > mounted outside. I have the tune power of the K3 set to 3 Watts. No > balun required. Works great, 80 through 10. > > Paul N4LCD > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 > ----------------------------------------- Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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>>>My doublet ladder line feeds straight into the K3 without external >>>tuner. Why use another box? >>> >>>David >>>G3UNA Because I already had the SGC-230 mounted outside. And my K3 was ordered with no tuner because I already had the SGC-230. (The Cobra Ultralite needs a tuner.) Paul N4LCD >>> > >Just passing along some information that might be of interest. >>> > >I have the K3 with the auto tuner built in. My antenna is a >>>Cobra Ultralite >>> > >fed with ladder line. I can switch between a Johnson Matchbox >>> and a > >BL2 >>> > >balun/KAT3 to feed the antenna. I previously had adjusted the feedline >>> > >length so that the Matchbox would find a 1 to 1 match on all bands 80 >>> > >through 10 including 30, 17, and 12 meters. I have received many >>>good signal >>> > >reports on all bands with either matching system. >>> > > >>> > ><snip> >>> > > >>> > >Happy 4th of July. >>> > > >>> > >73, >>> > > >>> > >John W2XS >>> > >>> > I have the same antenna, the Cobra Ultralite with window line, and >>> > simply connect the two ends of the window line to an SGC-230 >>> > automatic tuner http://www.sgcworld.com/230ProductPage.html which is >>> > mounted outside. I have the tune power of the K3 set to 3 Watts. No >>> > balun required. Works great, 80 through 10. >>> > >>> > Paul N4LCD _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Geoffrey Mackenzie-Kennedy wrote:
>Paul, > >When using a SGC-230 to feed two wire open wire line I understand >that one side of the feeder is connected to the SGC-230's ground terminal. That is correct. It's the lower wire of the window line in this picture: www.N4LCD.com/SGC-230_700x525.jpg >Have you found any RF appearing on the DC supply cable to the tuner, >or on the outside of the 50 ohm coax between the tuner and the >shack, which requires choking? I don't know if it was necessary, but I put a W2DU choke from The Wireman at the K3. I haven't used it without the W2DU choke. The ground terminal on the SGC-230 is not grounded. The K3 is grounded. No choke on the DC supply / control cable to the SGC-230. I have considered adding a few clamp on's. The rig is on the second floor, and the SGC-230 is mounted on the window sill just outside, on the second floor. I have the K3 set for 3 Watts for tuning. I normally have the K3 set for 5 Watts for CW or 10 Watts for SSB. I've never detected any RF problems. However I'm using a 10 Watt rig. YMMV with a 100 Watt K3. BTW, my intent is to ultimately have an 80 meter horizontal loop connected to the SGC-230, with no feed line. Paul >My reason for asking is that I am looking for another remote tuner >located outside for use with open wire feeder which does not cost a >fortune. The other remote tuner that I have is a classic link >coupled ATU, but it is already in use. > >73, >Geoff >GM4ESD > > >You wrote: > >>I have the same antenna, the Cobra Ultralite with window line, and >>simply connect the two ends of the window line to an SGC-230 >>automatic tuner http://www.sgcworld.com/230ProductPage.html which is >>mounted outside. I have the tune power of the K3 set to 3 Watts. No >>balun required. Works great, 80 through 10. _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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