KX1 and KXB3080 Builder Alert regarding TX on 80-m (L3 heating)
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KX1 and KXB3080 Builder Alert regarding TX on 80-m (L3 heating)
 
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It has been reported that L3 on the KX1's main board can become hot to
the touch when using the KX1 on 80 meters at full power (3 to 4 watts). We verified this in the lab. The temperature rises enough after a few seconds of continuous key-down time to cause a decrease in transmit power output and efficiency. The remedy is to increase the number of turns on L3 from 6 turns to 18 turns. This has no negative effect on any other band. Both the KX1 and KXB3080 manuals will be updated immediately to reflect this. We recommend that this change be made to all KX1s to be used on 80 meters. The change to L3 is best accomplished by removing the KX1's PC board from the case. All that is necessary is to remove the original 6-turn winding and rewind L3 with 18 turns of #26 enamel wire. If you don't have enough #26 enamel wire left over from the KX1 or another kit, we'll send you some upon request (send your request to [hidden email]). 73, Wayne N6KR --- http://www.elecraft.com _______________________________________________ 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 KXB3080 L3 Modification
The L3 Mod is complete and working fine. Before I installed the R11, R30 resistors, my KX1 power out with 13.7 VDC was: 80m 3.1 watts 40m 2.9 watts 30m 3.4 watts 20m 2.6 watts With the R11, R30 resistors installed and 13.7 VDC power out was: 80m 3.7 watts 40m 3.6 watts 30m 4.2 watts 20m 3.3 watts I just completed the L3 modification and my KX1 power out is: 80m 3.9 watts 40m 3.7 watts 30m 4.3 watts 20m 3.4 watts Power out was measured with into a DL1 (Dummy Load) and measured with a DMM. Granted the power out from beginning to end was not really that significant in the big scheme of things. It was simply an opportunity to burn some solder and learn a little more about my radios. I really do appreciate everything Wayne, Eric, Gary Surrency and everyone else at Elecraft continues to do for Elecraft builders, the general Ham population and myself. Three years ago I would have never dreamed of building a radio. Two years ago when I built my KX1, I prayed that I got everything right the first time, because I didn't think I would be able to find and fix any problems. Just thinking about winding Toroids put me into a sweat. Now it seems like one of the best things about being a ham is the tweaking, and fixing. Thank you so very much 73 KI4DGH Chuck Gehring _______________________________________________ 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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Now I'm a little less worried about the 3080 module, I guess it won't
turn the KX1 into a QRPp rig after all! 73 de Alex NS6Y On Apr 10, 2006, at 6:15 PM, Chuck Gehring wrote: > My KXB3080 L3 Modification > > The L3 Mod is complete and working fine. > > Before I installed the R11, R30 resistors, my KX1 power out with 13.7 > VDC > was: > > 80m 3.1 watts > 40m 2.9 watts > 30m 3.4 watts > 20m 2.6 watts > > With the R11, R30 resistors installed and 13.7 VDC power out was: > > 80m 3.7 watts > 40m 3.6 watts > 30m 4.2 watts > 20m 3.3 watts > > I just completed the L3 modification and my KX1 power out is: > > 80m 3.9 watts > 40m 3.7 watts > 30m 4.3 watts > 20m 3.4 watts > > 73 KI4DGH > Chuck Gehring _______________________________________________ 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 wayne burdick
Hi Gang Just done the L3 mod to my KX1 with the 8030 module fitted, I tried the radio before the mod and L3 did get warm with key down for a few seconds (about 5-10 secs), it’s a easy mod and didn’t take long to do, afterwards I did the same test with the new L3 and I can confirm that it certainly runs much cooler, after about 10 secs key down I could just tell that the core was slightly warmer than it was when I was in RX mode so I guess that’s fixed it!. I checked the power output levels before and after the mod and all seemed ok I seemed to have dropped about 100mW or so on 80m but gained a couple of hundred millwatts on other bands , in the real world the power remained about the same , between 3 and 4 watts on all bands. So im a happy chap. That’s the lid put back on the KX1 ,never to be removed again (Hi) well not till the SSB Module comes out! (Don’t Panic Wayne, only kidding) 73 Paul M0BMN -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.385 / Virus Database: 268.4.1/307 - Release Date: 10/04/2006 ___________________________________________________________ Yahoo! Photos – NEW, now offering a quality print service from just 8p a photo http://uk.photos.yahoo.com _______________________________________________ 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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