Low Power on 10 Meters
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Low Power on 10 Meters
 
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Folks,
I'm having a real struggle getting 6 to 7 WATTS on 28 Mhz while all other all other bands come up with a number well in excess of 10 Watts. Has anyone experienced this problem and was able to solve it? I'm suspecting low pass filters that are not coordinated to the 10 Meters Caps, if you can get my drift. I can't come up with a reason for this. In fact, it may make 10 Meters useless for some modes. Help? Bill NA7Y _______________________________________________ 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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Bill,
The most common cause of low output on 10 meters is T2 - be certain it is wound exactly like the illustration in the manual (except for the number of turns in the illustrations which may or may not be correct). The second thing is T4 - be certain it is wound as instructed in the manual. Thirdly, check the low pass filter for the correct number of turns on the toroids and check the capacitors. On the 10 meter band, spread the turns of the low pass filter inductors as much as you possibly can. 73, Don W3FPR William M. Spaulding, SR wrote: > Folks, > > I'm having a real struggle getting 6 to 7 WATTS on 28 Mhz while all other all other bands come up with a number well in excess of 10 Watts. > > Has anyone experienced this problem and was able to solve it? I'm suspecting low pass filters that are not coordinated to the 10 Meters Caps, if you can get my drift. I can't come up with a reason for this. In fact, it may make 10 Meters useless for some modes. > > Help? > > Bill > NA7Y 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 William M. Spaulding, SR
If all else is well, then consider how you are measuring it. As Don has
pointed out before, the internal power meter expects a 50 ohm load. After trying several configuration that showed 6w on 10m, I checked the dummy loads. All three were showing 1.2 swr with an analyzer. I then connected to my MFJ-949E with internal dummy load, and I connected so that the manual controls were in line, and adjusted for minimum SWR while hitting the tune button. When I did this and used the internal power meter, it showed 12w. None of my measurement setups were perfect, I was mainly looking at the spread of the readings. But when I used the setup described above, all my readings, on all bands, were above 12w. When read with external power meters, they fluctuated quite a bit more. David Wilburn [hidden email] K4DGW K2 #5982 William M. Spaulding, SR wrote: > Folks, > > I'm having a real struggle getting 6 to 7 WATTS on 28 Mhz while all other all other bands come up with a number well in excess of 10 Watts. > > Has anyone experienced this problem and was able to solve it? I'm suspecting low pass filters that are not coordinated to the 10 Meters Caps, if you can get my drift. I can't come up with a reason for this. In fact, it may make 10 Meters useless for some modes. > > Help? > > Bill > NA7Y > _______________________________________________ > 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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Dave,
That is an excellent method of achieving a 1:1 SWR with an unknown (or questionable) dummy load. Thanks for the reminder. Just be aware that the SWR=1 condition is frequency sensitive - the tuner must be retuned if the frequency or band is changed. 73, Don W3FPR David Wilburn wrote: > If all else is well, then consider how you are measuring it. As Don has > pointed out before, the internal power meter expects a 50 ohm load. > After trying several configuration that showed 6w on 10m, I checked the > dummy loads. All three were showing 1.2 swr with an analyzer. I then > connected to my MFJ-949E with internal dummy load, and I connected so > that the manual controls were in line, and adjusted for minimum SWR > while hitting the tune button. When I did this and used the internal > power meter, it showed 12w. > > None of my measurement setups were perfect, I was mainly looking at the > spread of the readings. But when I used the setup described above, all > my readings, on all bands, were above 12w. When read with external > power meters, they fluctuated quite a bit more. > > David Wilburn > [hidden email] > K4DGW > K2 #5982 > > > William M. Spaulding, SR wrote: >> Folks, >> >> I'm having a real struggle getting 6 to 7 WATTS on 28 Mhz while all >> other all other bands come up with a number well in excess of 10 Watts. >> >> Has anyone experienced this problem and was able to solve it? I'm >> suspecting low pass filters that are not coordinated to the 10 Meters >> Caps, if you can get my drift. I can't come up with a reason for >> this. In fact, it may make 10 Meters useless for some modes. >> >> Help? >> >> Bill >> NA7Y >> _______________________________________________ >> 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 > 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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That is absolutely right Don. I was playing with it several different
ways, and using the tune button and the manual tuner you could really see it jump when you got it "dialed in". The output of the power meter on the K2 was considerably more sensitive than the meter on the tuner, and was able to "peak" the setting looking at that. Worked great. Once I had seen your post, then tried that, and saw the numbers that I was getting, I was confident I had nothing to worry about. David Wilburn [hidden email] K4DGW K2 #5982 Don Wilhelm wrote: > Dave, > > That is an excellent method of achieving a 1:1 SWR with an unknown (or > questionable) dummy load. Thanks for the reminder. Just be aware that > the SWR=1 condition is frequency sensitive - the tuner must be retuned > if the frequency or band is changed. > > 73, > Don W3FPR > > David Wilburn wrote: >> If all else is well, then consider how you are measuring it. As Don >> has pointed out before, the internal power meter expects a 50 ohm >> load. After trying several configuration that showed 6w on 10m, I >> checked the dummy loads. All three were showing 1.2 swr with an >> analyzer. I then connected to my MFJ-949E with internal dummy load, >> and I connected so that the manual controls were in line, and adjusted >> for minimum SWR while hitting the tune button. When I did this and >> used the internal power meter, it showed 12w. >> >> None of my measurement setups were perfect, I was mainly looking at >> the spread of the readings. But when I used the setup described >> above, all my readings, on all bands, were above 12w. When read with >> external power meters, they fluctuated quite a bit more. >> >> David Wilburn >> [hidden email] >> K4DGW >> K2 #5982 >> >> >> William M. Spaulding, SR wrote: >>> Folks, >>> >>> I'm having a real struggle getting 6 to 7 WATTS on 28 Mhz while all >>> other all other bands come up with a number well in excess of 10 Watts. >>> >>> Has anyone experienced this problem and was able to solve it? I'm >>> suspecting low pass filters that are not coordinated to the 10 Meters >>> Caps, if you can get my drift. I can't come up with a reason for >>> this. In fact, it may make 10 Meters useless for some modes. >>> >>> Help? >>> >>> Bill >>> NA7Y >>> _______________________________________________ >>> 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 >> > 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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