Re: For you designer builders...
Great idea - a French DIY audio company offers these for sale (not
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John Bennett
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#6078
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Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
Yeah. That¡¯s where the ¡°DUH¡± came from¡
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton,
By
K9HZ
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#6077
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Re: For you designer builders...
I think that depends on the circumstances but yes the low noise parts make a much bigger difference.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
Owner
By
K9HZ
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#6076
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Re: For you designer builders...
Hi Bill
Not sure how true this is but apparently LM317 style regulators are better than the LM7805's.?? Not as good as a dedicated low noise part though for sure.
glenn
vk3ep
By
glenn
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#6075
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T41 BPF results
These are great, Oliver. If it's okay with you, could you send me the hi-rez versions of the graphs? Al and I would like to include them in the book.
BTW, I tweaked the toroids in the LPF board to
By
Jack, W8TEE
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#6074
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Re: CAT Transmit
All:
The final version of the code is about to be released by Al and I and we are turning it over to Oliver to care for it in the future. There are coding style differences that some people will
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Jack, W8TEE
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#6073
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Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
It's different for every different amp design... needs to be tested, BUT IN GENERAL you want enough headroom so that you never reach saturation of the devices... that means PTP power divided by
By
K9HZ
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#6072
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Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
*** Does it have to be 1/4? How much improvement would 1/2 of available
output give you?
I recently saw a new LDMOS device that's rated for 2.5kW CW output.
I think it runs off 75V. I was
By
jerry-KF6VB
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#6071
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Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
Easy to sacrifice gain to get negative feedback (and better linearity) when
power isn't an issue and there is excess gain available (e.g. low power
stages)
Much more expensive and risky to add high
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Gordon Gibby KX4Z
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#6070
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FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
More mumbling about APP¡ operating the amp at less than 25% of its average available output gives better IMD. DUH.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
By
K9HZ
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#6069
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FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
Well this is a load of crap. It¡¯s a good way to cover the problems up¡ that¡¯s all. Any RF engineer will tell you¡ stop it early in the design¡ not at the tailpipe.
Dr. William J.
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K9HZ
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#6068
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FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
There¡¯s that ¡°Class-A¡± thing again¡
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton,
By
K9HZ
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#6067
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FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
fyi
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C Operator
Villa Grand
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K9HZ
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#6066
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Re: RX-888
I¡¯m trying to get mine working and it appears the first step is to add the driver for the CYUSB chip to windows¡ but for some reason windows deactivates it and I can¡¯t get past that. Do you
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K9HZ
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#6065
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Re: RX-888
yes !
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mk3msm
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#6064
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RX-888
Anyone here have a RX-888 MK-II SDR working?
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
VP2EHZ
Owner - Operator
Big Signal Ranch - K9ZC
Staunton,
By
K9HZ
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#6063
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Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
Gary, I¡¯d like to see more here on this subject¡
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton,
By
K9HZ
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#6062
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Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
I am seeing results like this using a Radioberry driving your 20W amp.
Gary
W9TD
By
Gary
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#6061
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FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
Interesting¡
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C
By
K9HZ
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#6060
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Re: For you designer builders...
And these are not the kind of parts that even the most skilled builder would want to solder onto a board. If I ever do this, the boards will come pre-populated. They are 3mm x 3mm. YIKES!
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K9HZ
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#6059
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