KPA power out
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Had never checked the power out for my KPA-100, so did so. Took the KAT-100 out of the chain for the test, using dummy load. Startled by the results:
band K2 KPA-100 KPA-100 thru ATU no ATU 160 ------- 10.7 ---------100 --------- 100 80 ------- 15.0 ---------100 --------- 100 40 ------- 14.1 --------- 90 --------- 90 30 ------- 14.2 --------- 80 --------- 80 20 ------- 14.5 --------- 50 --------- 50 17 ------- 14.4 --------- 60 --------- 60 15 ------- 14.5 --------- 60 --------- 60 12 ------- 14.1 ---------100 --------- 40 10 ------- 14.7 ---------100 --------- 25 Dunno what to make of it. 73 Fred kt5x _______________________________________________ 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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Fred KT5X wrote:
Took the KAT-100 out of the chain for the test, using dummy load. Startled by the results: band K2 KPA-100 KPA-100 thru ATU no ATU 160 ------- 10.7 ---------100 --------- 100 80 ------- 15.0 ---------100 --------- 100 40 ------- 14.1 --------- 90 --------- 90 30 ------- 14.2 --------- 80 --------- 80 20 ------- 14.5 --------- 50 --------- 50 17 ------- 14.4 --------- 60 --------- 60 15 ------- 14.5 --------- 60 --------- 60 12 ------- 14.1 ---------100 --------- 40 10 ------- 14.7 ---------100 --------- 25 Dunno what to make of it. -------------------------------------- Something isn't right in both the KPA100 and ATU from the looks of it, Fred! I can't speak to the ATU issue of poor efficiency on 10/12 meters since I don't have a KAT100. The droop on 30-15 meters from the KPA100 suggests an issue with the bandpass filters. The KPA100 typically exceeds 100 watts output quite easily. The fact that yours doesn't suggests low supply voltage or a measurement error that is showing a slightly low output across the board. Suggest you look very closely at your bandpass filter components for the low bands. The KPA100 manual also has a procedure for checking the bandpass filters using an antenna analyzer, if you have access to one. Just for the "record", here's what my K2/100 delivers at full power into a dummy load: 160: 112 watts 80: 108 watts 60: 110 watts (legal limit on this band is 50 watts erp, of course) 40: 112 watts 30: 107 watts 20: 105 watts 18: 111 watts 15: 106 watts 12: 104 watts 10: 106 watts at 28 MHz, 46 watts at 29.5 MHz That roll-off at the upper limit of 10 meters is normal I believe. Of course the difference between 100 watts and 112 watts in what another Ham will hear on the air is completely insignificant, but it demonstrates that the KPA100 will meet the 100 watt transmit specification across the HF bands. Ron AC7AC _______________________________________________ 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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Correction!
Don, W3FPR, kindly brought to my attention that in my comments below I mistakenly referred to the KPA100 output filters as bandpass filters. They are actually low-pass filters. The problem seems to be in the KPA100's low-pass output filters, NOT in the K2's bandpass output filters. Ron AC7AC -----Original Message----- From: elecraft-bounces+rondec=[hidden email] [mailto:elecraft-bounces+rondec=[hidden email]] On Behalf Of Ron D'Eau Claire Sent: Thursday, May 26, 2005 7:52 AM To: [hidden email] Subject: RE: [Elecraft] KPA power out Fred KT5X wrote: Took the KAT-100 out of the chain for the test, using dummy load. Startled by the results: band K2 KPA-100 KPA-100 thru ATU no ATU 160 ------- 10.7 ---------100 --------- 100 80 ------- 15.0 ---------100 --------- 100 40 ------- 14.1 --------- 90 --------- 90 30 ------- 14.2 --------- 80 --------- 80 20 ------- 14.5 --------- 50 --------- 50 17 ------- 14.4 --------- 60 --------- 60 15 ------- 14.5 --------- 60 --------- 60 12 ------- 14.1 ---------100 --------- 40 10 ------- 14.7 ---------100 --------- 25 Dunno what to make of it. -------------------------------------- Something isn't right in both the KPA100 and ATU from the looks of it, Fred! I can't speak to the ATU issue of poor efficiency on 10/12 meters since I don't have a KAT100. The droop on 30-15 meters from the KPA100 suggests an issue with the bandpass filters. The KPA100 typically exceeds 100 watts output quite easily. The fact that yours doesn't suggests low supply voltage or a measurement error that is showing a slightly low output across the board. Suggest you look very closely at your bandpass filter components for the low bands. The KPA100 manual also has a procedure for checking the bandpass filters using an antenna analyzer, if you have access to one. Just for the "record", here's what my K2/100 delivers at full power into a dummy load: 160: 112 watts 80: 108 watts 60: 110 watts (legal limit on this band is 50 watts erp, of course) 40: 112 watts 30: 107 watts 20: 105 watts 18: 111 watts 15: 106 watts 12: 104 watts 10: 106 watts at 28 MHz, 46 watts at 29.5 MHz That roll-off at the upper limit of 10 meters is normal I believe. Of course the difference between 100 watts and 112 watts in what another Ham will hear on the air is completely insignificant, but it demonstrates that the KPA100 will meet the 100 watt transmit specification across the HF bands. Ron AC7AC _______________________________________________ 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 _______________________________________________ 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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