6500 power

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The power meter on my 6500 shows a maximum of 85W. I checked with LS2K4 Wattmeter that is a little bit more accurate than a bird and tha value is correct. Power supply gives 13,53V. Why my Flex doesn't give full power ouput? The specifications says 100W if am not wrong. I read some posts on the same matter but I didn't undestood if this is a general problem, there is a fault on my 6500 or what else. 15W missing on 100W it's a lot...
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Stefano - W2WTZ

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Posted 3 years ago

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HCampbell WB4IVF

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The K3 has exceptionally clean keying sidebands, among the best if not the best from what I read, but there was much more to the ARRL tx testing.  I would also consider the other test results. 

 For another perspective, here’s a link to Adam Farson/AB4OJ’s test report site, which contains his Flex 6700 test report (note that tx testing was conducted at 100W):

http://www.ab4oj.com/test/reports.html

BTW, Adam also has a new presentation on the site (under Test Methods and Procedures): A New Look at SDR [receiver] Testing

Update:

I just did a quick search here and found this very interesting discussion:

 https://community.flexradio.com/flexradio/topics/flex-6700-v-elecraft-k3-cw-bandwidth-measurements

 

(Edited)
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Gerald - K5SDR, Employee

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[I am posting this in two places because there are two references to the same comparison]

It is important to note that CW keying sidebands (Figure 2) have nothing to do with PA linearity or power output.  CW and RTTY are not linear modes and can even be run in Class C with no problem.  CW keying sidebands are generated strictly by the rise time characteristics of the keying waveform.  The faster the rise time, the wider the bandwidth.   Since the ARRL review was done we have slowed the rise time down based on recommendations from Rob Sherwood so QST review is totally out of date.  The CW rise time and wave shape is strictly a software controlled function and can easily be changed.  

For linear operation (SSB, PSK, etc.) you need to compare the "Third-order intermodulation distortion (IMD) products" under the Transmitter section.  Note that the K3 was shown to be adjustable to 116W.  That is what I mean by letting the control go above 100W, which we could do to without re-calibration.

The direct comparison for IMD between the K3 and 6700 are copied below from the respective QST reviews for for the worst case band 3rd/5th/7th/9th order TX IMD are:

K3: -29/-43/-46/-51
6700: -32/-51/-52/-52

This is the relevant comparison for the context of power output vs IMD.  CW keying bandwidth is a totally different subject.

Gerald
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HCampbell WB4IVF

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If Flex goes to “11”, someone is likely to notice/report increased IMD the next time the radio is tested, and here we go again.  My vote would be to keep it as is, and maybe expand a little in the documentation, as has been suggested.  Not a big deal to me either way.  Other future updates are much more important to me. 

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Bill -VA3WTB

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More companies should take Flex lead on this. I hardly think this is effecting sales. I can't prove this, but I bet 95% of owners care less about it as most use an amp anyways. But this has given a few a reason to take Gerald to task over it.
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W5XZ - dan

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Gerald, can I send my radio in and get it cranked up to 150w?  I very rarely use ssb or digi modes...99.5% cw here...using old fashioned, low gain, grounded grid, tube finals..

unless i'm mis-reading the spec sheet for the RD100HHF ( VERY possible ), these things should be good for 100w a piece, right?  I do appreciate there is negative feedback from drains to gates, but there are 2 devices in push pull.

or, maybe, 'a few lines of code', to put the final in class C on cw, maybe ??

regards, dan, W5XZ
(Edited)
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Gerald - K5SDR, Employee

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Dan, in a word no.  That would take you into total saturation at 13.8V, which would be more like class D.  You would need to run the parts at higher voltage than allowed for the rest of the radio, which is limited to 16V max.  
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W5XZ - dan

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ok, then here's a vote for "110" ( or more ), from software.

thanks, gerald
 
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Ken - NM9P, Elmer

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Gerald, I would cast my vote to keep the TX Cleaner, even at the expense of a few Watts...  at least until adaptive predistortion makes it possible to tweak a little more power out cleanly (If that is possible).  If the dial goes to "11" there are going to be those who will always run full throttle no matter what the effect upon their signals, or their neighbors.  That would be bad for the hobby, and bad for the reputation of Flexradio.
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Ken - NM9P, Elmer

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Gerald, I would cast my vote to keep the TX Cleaner, even at the expense of a few Watts...  at least until adaptive predistortion makes it possible to tweak a little more power out cleanly (If that is possible).  If the dial goes to "11" there are going to be those who will always run full throttle no matter what the effect upon their signals, or their neighbors.  That would be bad for the hobby, and bad for the reputation of Flexradio.
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Stefano - W2WTZ

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DDutil gives me 13,9V, on front display of 6500 the first two numbers I read are 13.62 - 13.46. Which is the correct voltage that arrives at the radio? What represents all the numbers I see on display?
Gerald, thank you once more for your contribute. Pls evaluate to leave the adjustments as they are and instead modify the technical specifications in the way they are written.
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Tim - W4TME, Customer Experience Manager

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The first voltage value is the voltage before the main fuse.  The second voltage is after the main fuse.  Always expect the 2nd voltage value to be less than the first.
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Gerald - K5SDR, Employee

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The first voltage value is the one that is closest (but not exact due to IR drops) to the value seen by the PA transistors.  This is after the 30A fuse on the input of the PA.  the second number is after the 5A fuse on the transceiver board.
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Stefano - W2WTZ

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Thank you boh for explanation. If I well understood, I should read 13,8v in the first field in order to get full power from PA board right? I wish to supply correct voltage to PA, then place the radio in FM and pressing ptt, power out a dummy load with swr less than 1,03:1.My wattmeter has an accuracy of +/- 5% in worst case. This means that if I read a power out of about 90/92W in all the bands, my Flex works well and it's not necessary to open any ticket I hope.