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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*\[Amps\]\s+160m\s+mosfet\s+linear\s+amplifier\s+problem\s+with\s+ferrite\s+cores\s*$/: 38 ]

Total 38 documents matching your query.

21. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: Ron Youvan <ka4inm@tampabay.rr.com>
Date: Sun, 18 Apr 2010 12:16:59 +0000
I suggested replacing the broken core and testing at 67 and 1.2 MHz to see if the frequency extreme is a problem. -- Ron KA4INM - The next election, I know what is going to happen, I'm going to help.
/archives//html/Amps/2010-04/msg00532.html (9,379 bytes)

22. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: sasas asasas <tzitzikas_ee@yahoo.com>
Date: Sun, 18 Apr 2010 07:45:33 -0700 (PDT)
do you mean to test at 1.2mhz with 67 material ferrite or the test at 67mhz and 1.2mhz with the same 43 material ferrite?    I suggested replacing the broken core and testing at 67 and 1.2 MHz to see
/archives//html/Amps/2010-04/msg00535.html (9,940 bytes)

23. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: sasas asasas <tzitzikas_ee@yahoo.com>
Date: Sun, 18 Apr 2010 08:00:49 -0700 (PDT)
i think that the proper material is 43 or 77 for frequences between 1-2mhz. i search in some internet sites and i found these: 31 Material A MnZn ferrite designed specifically for EMI suppression app
/archives//html/Amps/2010-04/msg00536.html (10,914 bytes)

24. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: sasas asasas <tzitzikas_ee@yahoo.com>
Date: Sun, 18 Apr 2010 05:03:39 -0700 (PDT)
The linear have been constructed by me (if you mean the manufacter of linear amplifier). The prototype have been constructed by schematic designer and you can see a photo here: http://www.tzitzikas.w
/archives//html/Amps/2010-04/msg00537.html (18,427 bytes)

25. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: Rob Stampfli <rob@cboh.org>
Date: Sun, 18 Apr 2010 13:11:01 -0400
When I was experimenting with common mode chokes on 160m and 80m, I tried type 77 toroids, and although they worked quite well, they overheated very easily. Type 43 toroids, although spec-wise seemin
/archives//html/Amps/2010-04/msg00538.html (10,280 bytes)

26. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Sun, 18 Apr 2010 19:25:47 +0100
Sasas I looked at the ARRL site for a similar power amplifier to compare notes. http://www.w6kan.com/ssamp.html The devices are completely different and so is the supply voltage, but the push pull ar
/archives//html/Amps/2010-04/msg00542.html (10,302 bytes)

27. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Sun, 18 Apr 2010 20:20:58 +0100
Check the sense of all the windings, particularly T3 and check all your ferrites are isolated from the windings and everything else - the material is conductive. David _______________________________
/archives//html/Amps/2010-04/msg00543.html (9,514 bytes)

28. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: "alexeban" <alexeban@gmail.com>
Date: Mon, 19 Apr 2010 10:15:26 +0300
Guys, the problem is more pernicious than that! The problem is in the way the transformers are WOUND! Efficient high power transformers are wound using transmission line coupling, not flux link coupl
/archives//html/Amps/2010-04/msg00555.html (12,510 bytes)

29. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: sasas asasas <tzitzikas_ee@yahoo.com>
Date: Mon, 19 Apr 2010 00:20:50 -0700 (PDT)
for 1-2mhz operation, what kind of material do you propose? 31, 43 or 77 material??? Guys, the problem is more pernicious than that! The problem is in the way the transformers are WOUND! Efficient hi
/archives//html/Amps/2010-04/msg00556.html (12,688 bytes)

30. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: <d.cutter@ntlworld.com>
Date: Mon, 19 Apr 2010 13:09:47 +0100
Alex I'm not sure if you would call 500W 'high power' - I would from a UK perspective. In the classic EB104 I see ordinary transformers. Perhaps I'm not understanding something, you're the expert. Wh
/archives//html/Amps/2010-04/msg00557.html (10,406 bytes)

31. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: "Joe Subich, W4TV" <lists@subich.com>
Date: Mon, 19 Apr 2010 10:23:21 -0400
This is not a "500W" amplifier. This claims to be a 2KW PEP amplifier - in AM PEP is 4 x carrier. In this case an amplifier spec'd for "500W AM" would be 4 x 500 = 2000. 73, ... Joe Subich, W4TV ___
/archives//html/Amps/2010-04/msg00559.html (11,899 bytes)

32. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: <d.cutter@ntlworld.com>
Date: Mon, 19 Apr 2010 15:38:57 +0100
Thanks, Joe, I lost site of that. David G3UNA _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2010-04/msg00560.html (9,778 bytes)

33. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: Ron Youvan <ka4inm@tampabay.rr.com>
Date: Mon, 19 Apr 2010 11:25:36 -0400
The trouble is: I don't think this amplifier using "switching FETs" instead of "RF FETs" is capable of inputting enough DC power to output 2,000 Watts of peak envelope power. 110 Volts X 16 Amps = 1
/archives//html/Amps/2010-04/msg00561.html (9,966 bytes)

34. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Tue, 20 Apr 2010 06:46:56 +0100
Apparently, Sassas has friends who have done so. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2010-04/msg00566.html (10,082 bytes)

35. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: "Alex Eban" <alexeban@gmail.com>
Date: Tue, 20 Apr 2010 12:32:29 +0300
First of all the guy INSULATED the FET's from the heatsink! You can see the mica insulators of the side plate where the transistors are mounted. He also used a WIDE copper strip to connect the drains
/archives//html/Amps/2010-04/msg00567.html (13,449 bytes)

36. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: "Alex Eban" <alexeban@gmail.com>
Date: Tue, 20 Apr 2010 12:48:54 +0300
Hi guys: Read this especially the passage about #43 material: Following is a list of large size Ferrite Beads (FB), Ferrite Toroidal Cores (FT), and Split Ferrite Cores (2X), all of which are extensi
/archives//html/Amps/2010-04/msg00568.html (13,923 bytes)

37. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: sasas asasas <tzitzikas_ee@yahoo.com>
Date: Tue, 20 Apr 2010 08:09:59 -0700 (PDT)
the manufacturer who construct the prototype and use mica to the fets, propose to me. to not use mica, but to take the drain for the 6 fets from the heatsink. He told me just to use some thermal sili
/archives//html/Amps/2010-04/msg00570.html (13,802 bytes)

38. Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores (score: 1)
Author: sasas asasas <tzitzikas_ee@yahoo.com>
Date: Tue, 20 Apr 2010 10:50:53 -0700 (PDT)
hi. The manufacturer and another radio amateur claim that this linear amplifier which they have constructed works perfectly and stable, and gives 400w minimum r.f power at output stage (with 110vdc p
/archives//html/Amps/2010-04/msg00571.html (15,797 bytes)


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