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[SPAM] Re: [BITX20] Replacing the PA section on Bitx 40

K9HZ All Messages By This Member #40948 开云体育 Also… have you had it on the air like that yet? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: *Like us on Facebook!* ? ? email:? bill@... ? toggle quoted message Show quoted text From: [email protected] [mailto:[email protected]] On Behalf Of Raj vu2zap Sent: Thursday, February 01, 2018 4:24 AM To: [email protected] Subject: [SPAM] Re: [BITX20] Replacing the PA section on Bitx 40 ? Here is how I made the socket and mounted the RDD16 Note the RDD is reversed and? then the gate is actually soldered to the IRF gate line which goes behind the FET. Now I can use either of them.. You will need to think of a heat sink plate that fits this way! At 01/02/2018, you wrote: Why replace everything??? You can probably put it in place of the 510 (making sure it is pinned correctly, of course).? ? I am waiting on a pair, myself, that I will be stuffing into the ubitx.?? ? I want to even out the power output.?? I will also try a resistor/capacitor in parallel, in series with the gate, to try and even out the frequency response.?? I am thinking 4.7 ohm & 4700pf.?? I will also try 6.8 ohm & 4700pf.?? Depends on how flat I can get the output. Marco - KG5PRT? On Jan 31, 2018 10:12 PM, "James Lawrie" <lawriejk@...> wrote: Hello, My shipment of replacement RF Mosfets have arrived and I want to replace the on board PASection with one based on the RD16HHF1. It will be a separate small PCB based on the reference design shown in the data sheet. I need help from the professionals here as to where to attach the new PA board. I know it would be somewhere after the 2N2219A driver, and I want to remove all bypassed SMTs and or other parts from the Bitx board in that area. If you have a pretty good idea could you please let me know, and possibly a drawing if you could. This should keep me busy and off the forum for a while.
Raj vu2zap Member Profile All Messages By This Member #40955 Transmits fine Bill! I have not experimented with correct bias setting but I was running more than 100 mils bias.. That board got displaced by the new toy uBitx.. I'll be back to it later later. At 01/02/2018, you wrote: toggle quoted message Show quoted text Also… have you had it on the air like that yet? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: *Like us on Facebook!* ? ? email:? bill@... ? From: [email protected] [ mailto:[email protected]] On Behalf Of Raj vu2zap Sent: Thursday, February 01, 2018 4:24 AM To: [email protected] Subject: [SPAM] Re: [BITX20] Replacing the PA section on Bitx 40 ? Here is how I made the socket and mounted the RDD16 Note the RDD is reversed and? then the gate is actually soldered to the IRF gate line which goes behind the FET. Now I can use either of them.. You will need to think of a heat sink plate that fits this way!
M Garza #40963 From what I read, bias should be between 300 to 500ma.? Can anyone confirm this? I like your socket idea, Raj.? Very good idea.? Makes experimenting easier. Marco - KG5PRT? toggle quoted message Show quoted text On Feb 1, 2018 8:09 AM, "Raj vu2zap" <rajendrakumargg@...> wrote: Transmits fine Bill! I have not experimented with correct bias setting but I was running more than 100 mils bias.. That board got displaced by the new toy uBitx.. I'll be back to it later later. At 01/02/2018, you wrote: Also… have you had it on the air like that yet? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: *Like us on Facebook!* ? ? email:? bill@... ? From: [email protected] [ mailto:[email protected]] On Behalf Of Raj vu2zap Sent: Thursday, February 01, 2018 4:24 AM To: [email protected] Subject: [SPAM] Re: [BITX20] Replacing the PA section on Bitx 40 ? Here is how I made the socket and mounted the RDD16 Note the RDD is reversed and? then the gate is actually soldered to the IRF gate line which goes behind the FET. Now I can use either of them.. You will need to think of a heat sink plate that fits this way!
Lawrence Galea All Messages By This Member #40970 Standing current in the G6ALU 20W amplifier with two D16HHF1 in push-pull is set to 250 mA each Regards Lawrence toggle quoted message Show quoted text On Thu, Feb 1, 2018 at 4:56 PM, M Garza <mgarza896@...> wrote: From what I read, bias should be between 300 to 500ma.? Can anyone confirm this? I like your socket idea, Raj.? Very good idea.? Makes experimenting easier. Marco - KG5PRT? On Feb 1, 2018 8:09 AM, "Raj vu2zap" <rajendrakumargg@...> wrote: Transmits fine Bill! I have not experimented with correct bias setting but I was running more than 100 mils bias.. That board got displaced by the new toy uBitx.. I'll be back to it later later. At 01/02/2018, you wrote: Also… have you had it on the air like that yet? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: *Like us on Facebook!* ? ? email:? bill@... ? From: [email protected] [ mailto:[email protected]] On Behalf Of Raj vu2zap Sent: Thursday, February 01, 2018 4:24 AM To: [email protected] Subject: [SPAM] Re: [BITX20] Replacing the PA section on Bitx 40 ? Here is how I made the socket and mounted the RDD16 Note the RDD is reversed and? then the gate is actually soldered to the IRF gate line which goes behind the FET. Now I can use either of them.. You will need to think of a heat sink plate that fits this way!
M Garza #40971 Thanks! I was looking at this schematic: It showed different current levels for the bias. Marco - KG5PRT toggle quoted message Show quoted text On Thu, Feb 1, 2018 at 10:43 AM, Lawrence Galea <9h1avlaw@...> wrote: Standing current in the G6ALU 20W amplifier with two D16HHF1 in push-pull is set to 250 mA each Regards Lawrence On Thu, Feb 1, 2018 at 4:56 PM, M Garza <mgarza896@...> wrote: From what I read, bias should be between 300 to 500ma.? Can anyone confirm this? I like your socket idea, Raj.? Very good idea.? Makes experimenting easier. Marco - KG5PRT? On Feb 1, 2018 8:09 AM, "Raj vu2zap" <rajendrakumargg@...> wrote: Transmits fine Bill! I have not experimented with correct bias setting but I was running more than 100 mils bias.. That board got displaced by the new toy uBitx.. I'll be back to it later later. At 01/02/2018, you wrote: Also… have you had it on the air like that yet? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: *Like us on Facebook!* ? ? email:? bill@... ? From: [email protected] [ mailto:[email protected]] On Behalf Of Raj vu2zap Sent: Thursday, February 01, 2018 4:24 AM To: [email protected] Subject: [SPAM] Re: [BITX20] Replacing the PA section on Bitx 40 ? Here is how I made the socket and mounted the RDD16 Note the RDD is reversed and? then the gate is actually soldered to the IRF gate line which goes behind the FET. Now I can use either of them.. You will need to think of a heat sink plate that fits this way!
Jerry Gaffke All Messages By This Member #40996 Farhan recommends 100ma for the push-pull IRF510's on the uBitx. More is better, you get into a more linear region of the FET. But more means more power getting sucked from the battery if portable, that power gets dissipated as heat in the FET's. I'm going with 100ma. With a 500ma quiescent drain current when using a 24v supply, each FET is dissipating 240.5 = 12 Watts. That's a lot of heat. Back of to 100ma and it is only 240.1 = 2.4 Watts. Which still seems plenty. You want to be very careful when adjusting those IRF510 gate bias trim-pots, take it too far and those IRF510's might be trying to dump 100 Watts or so. Jerry toggle quoted message Show quoted text On Thu, Feb 1, 2018 at 08:56 am, M Garza wrote: I was looking at this schematic: It showed different current levels for the bias. ?
M Garza #40999 Jerry, The bias amount I was referring to was for the RD16HHF1s, not the IRF510s. Thanks. Marco - KG5PRT toggle quoted message Show quoted text On Thu, Feb 1, 2018 at 1:42 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: Farhan recommends 100ma for the push-pull IRF510's on the uBitx. More is better, you get into a more linear region of the FET. But more means more power getting sucked from the battery if portable, that power gets dissipated as heat in the FET's. I'm going with 100ma. With a 500ma quiescent drain current when using a 24v supply, each FET is dissipating 240.5 = 12 Watts. That's a lot of heat. Back of to 100ma and it is only 240.1 = 2.4 Watts. Which still seems plenty. You want to be very careful when adjusting those IRF510 gate bias trim-pots, take it too far and those IRF510's might be trying to dump 100 Watts or so. Jerry On Thu, Feb 1, 2018 at 08:56 am, M Garza wrote: I was looking at this schematic: It showed different current levels for the bias. ?

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