Tuning K3 with linear amp
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I am still exploring my new K3 (it's less than one week old. I discovered
an odd issue while tuning it with my Commander HF 2500 amp. With the ATU off and the power lowered to about 3 watts I activated the tune function. While watching the output on my Coaxial Dynamics wattmeter I gradually raised the K3 output power while tuning the amp. When I got to around 13 watts drive from the K3, the wattmeter was showing a carrier power of 1 KW from the amp. The drive power of 13 watts indicated on the K3 was unusually low for an indicated output of 1 KW carrier. When I then spoke into the mike and flipped on the peak reading circuit on the watt meter, it showed only 500 to 600 watts pep which was low in my experience. Usually with an indicated carrier power of 1 KW I should at least get around 1400 or more indicated peak power on modulation. I gradually increased the drive from the K3 until the peaks showed 1 KW or a bit more. When I again checked the output of the K3 it showed a bit more than 23-25 watts which is what I usually get with my other radios. This behavior is different than my other radios. It appears to require a low drive level to show 1 KW carrier output from the amp but with a low peak reading. I suspect something is happening with the ALC but I'm not sure. I should mention that I have yet to load any firmware updates. It has whatever version it had when it left Aptos on May 2. Could that be a factor? Bruce - W8FU _______________________________________________ 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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Bruce,
Yes, do load the latest firmware. It does contain some ALC changes. 73, Don W3FPR Bruce McLaughlin wrote: > I am still exploring my new K3 (it's less than one week old. I discovered > an odd issue while tuning it with my Commander HF 2500 amp. With the ATU > off and the power lowered to about 3 watts I activated the tune function. > While watching the output on my Coaxial Dynamics wattmeter I gradually > raised the K3 output power while tuning the amp. When I got to around 13 > watts drive from the K3, the wattmeter was showing a carrier power of 1 KW > from the amp. The drive power of 13 watts indicated on the K3 was unusually > low for an indicated output of 1 KW carrier. When I then spoke into the > mike and flipped on the peak reading circuit on the watt meter, it showed > only 500 to 600 watts pep which was low in my experience. Usually with an > indicated carrier power of 1 KW I should at least get around 1400 or more > indicated peak power on modulation. I gradually increased the drive from > the K3 until the peaks showed 1 KW or a bit more. When I again checked the > output of the K3 it showed a bit more than 23-25 watts which is what I > usually get with my other radios. > > This behavior is different than my other radios. It appears to require a > low drive level to show 1 KW carrier output from the amp but with a low peak > reading. I suspect something is happening with the ALC but I'm not sure. I > should mention that I have yet to load any firmware updates. It has > whatever version it had when it left Aptos on May 2. Could that be a > factor? > > Bruce - W8FU > > 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 |
RE: Tuning K3 with linear amp
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Thanks Don. I will do that very soon.
Bruce - W8FU -----Original Message----- From: Don Wilhelm [mailto:[hidden email]] Sent: Monday, May 12, 2008 7:19 PM To: Bruce McLaughlin Cc: [hidden email] Subject: Re: [Elecraft] Tuning K3 with linear amp Bruce, Yes, do load the latest firmware. It does contain some ALC changes. 73, Don W3FPR Bruce McLaughlin wrote: > I am still exploring my new K3 (it's less than one week old. I discovered > an odd issue while tuning it with my Commander HF 2500 amp. With the ATU > off and the power lowered to about 3 watts I activated the tune function. > While watching the output on my Coaxial Dynamics wattmeter I gradually > raised the K3 output power while tuning the amp. When I got to around 13 > watts drive from the K3, the wattmeter was showing a carrier power of 1 KW > from the amp. The drive power of 13 watts indicated on the K3 was unusually > low for an indicated output of 1 KW carrier. When I then spoke into the > mike and flipped on the peak reading circuit on the watt meter, it showed > only 500 to 600 watts pep which was low in my experience. Usually with an > indicated carrier power of 1 KW I should at least get around 1400 or more > indicated peak power on modulation. I gradually increased the drive from > the K3 until the peaks showed 1 KW or a bit more. When I again checked the > output of the K3 it showed a bit more than 23-25 watts which is what I > usually get with my other radios. > > This behavior is different than my other radios. It appears to require a > low drive level to show 1 KW carrier output from the amp but with a low peak > reading. I suspect something is happening with the ALC but I'm not sure. I > should mention that I have yet to load any firmware updates. It has > whatever version it had when it left Aptos on May 2. Could that be a > factor? > > Bruce - W8FU > > -- No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.16/1429 - Release Date: 5/12/2008 6:14 PM _______________________________________________ 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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