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Hi All, Does anyone have built this little marvel? Any thoughts? I'm guessing the only mod(s) needed to move it to 40m is the LPF and maybe L1, am I right? Gonna get another 12V battery ASAP.  found it here: 73, Dan HK4DEI
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i built a similar linear for 40/20. it works very well. - f
On 7 Jul 2017 2:01 p.m., "Daniel Isaza" < hk4dei@...> wrote: Hi All,
Does anyone have built this little marvel? Any thoughts? I'm guessing the only mod(s) needed to move it to 40m is the LPF and maybe L1, am I right?
Gonna get another 12V battery ASAP.
found it here:
73,
Dan
HK4DEI
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Thanks a lot Farhan!
That's perfect, I'm building it today. What a nice and simple circuit, respectable power output and also a great detailed post on your blog. FB! Dan.
On Fri, Jul 7, 2017 at 11:46 AM, Ashhar Farhan <farhanbox@...> wrote:
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If you have a Bitx40 it already has a comparable IRF510 linear amp,
giving around 20 to 25 Watts when powered from 24v.
I do like the LED RF detector on the output.
Jerry
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Show quoted text
On Fri, Jul 7, 2017 at 10:10 am, Daniel Isaza wrote:
Thanks a lot Farhan!
That's perfect, I'm building it today. What a nice and simple circuit, respectable power output and also a great detailed post on your blog. FB!
Dan.
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Hi Jerry,
Yeah, my BitX is fine as it is, even at 5W, 12V. I'm thinking about hooking it up to some other HB rigs begging for more power... putting about 0.5 ~ 2W out on CW or DSB. Gotta love the simplicity of single ended PA's.
73!,Dan.
On Fri, Jul 7, 2017 at 2:36 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: If you have a Bitx40 it already has a comparable IRF510 linear amp,
giving around 20 to 25 Watts when powered from 24v.
I do like the LED RF detector on the output.
Jerry
On Fri, Jul 7, 2017 at 10:10 am, Daniel Isaza wrote:
Thanks a lot Farhan!
That's perfect, I'm building it today. What a nice and simple circuit, respectable power output and also a great detailed post on your blog. FB!
Dan.
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What do folks do for the Mica Caps in all these
band pass filters.
In the old days I had lots.? I know they are
great and usually over 200V.
But I see they are $2-3!! EACH! Ouch!? Mouser has
some.
Mike, WA6ISP
On 7/7/2017 12:36 PM, Jerry Gaffke via
Groups.Io wrote:
If you have a Bitx40 it already has a comparable
IRF510 linear amp,
giving around 20 to 25 Watts when powered from 24v.
I do like the LED RF detector on the output.
Jerry
On Fri, Jul 7, 2017 at 10:10 am, Daniel Isaza wrote:
Thanks a lot Farhan!
That's perfect, I'm building it today. What a nice and simple
circuit, respectable power output and also a great detailed
post on your blog. FB!
Dan.
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
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Did you try kitsandparts? They have 'em [depending on value] as low as 1.30 ea.
Vince.
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Show quoted text
On 07/07/2017 05:35 PM, Michael Hagen wrote: What do folks do for the Mica Caps in all these band pass filters.
In the old days I had lots. I know they are great and usually over 200V.
But I see they are $2-3!! EACH! Ouch! Mouser has some.
Mike, WA6ISP
On 7/7/2017 12:36 PM, Jerry Gaffke via Groups.Io wrote:
If you have a Bitx40 it already has a comparable IRF510 linear amp,
giving around 20 to 25 Watts when powered from 24v.
I do like the LED RF detector on the output.
Jerry
On Fri, Jul 7, 2017 at 10:10 am, Daniel Isaza wrote:
Thanks a lot Farhan!
That's perfect, I'm building it today. What a nice and simple
circuit, respectable power output and also a great detailed post
on your blog. FB!
Dan.
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
--
Michigan VHF Corp.
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Mike:
As noted in the notes to the amplifier, Farhan uses ceramic capacitors AND
recommends a maximum RF voltage of 50v or so.
Mica caps are the best for such an application, but good ones
nowadays are very expensive. Dan's Small Parts and Kits has some.
He used to have many more but surplus ones are getting rare (n.b.).
Note that there are some some still made, but their quality is questionable,
at least from my experience. Mouser at least checks the quality...
john
AD5YE
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Yeah, I forgot about Diz. He's good. He also has a toroid kit for the
WA2EBY LPF assembly, but not a cap kit as far as I know...
john
AD5YE
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Note that this particular design is for 80 meters.
It is tough to make the IRF530 work on 40 or 20 meters,
much less at 15 meters or above...
Use the IRF510 or equivalent (BUZ21/24/44) instead.
john
AD5YE
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"Yeah, I forgot about Diz. He's good. He also has a toroid kit for the
WA2EBY LPF assembly, but not a cap kit as far as I know...
john
AD5YE"
Diz might put together a mica cap kit for the wa2eby amplifier. Someone would have to ask him. That's how the toroid kit came to be. I asked him. I bought all of the mica caps from Mouser.
Leonard
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Diz's company, Kits And Parts, is a gold mine for hard-to-find caps and toroids. A friend of mine has one of his One Watters and it's a fun little rig. Keep him in mind when you're building.
Jack, W8TEE
From: Leonard <dredger@...>
To: [email protected]
Sent: Friday, July 7, 2017 8:23 PM
Subject: Re: [BITX20] 80m hexfet power amplifier by W7ZOI
"Yeah, I forgot about Diz. He's good. He also has a toroid kit for the
WA2EBY LPF assembly, but not a cap kit as far as I know...
john
AD5YE"
Diz might put together a mica cap kit for the wa2eby amplifier. Someone would have to ask him. That's how the toroid kit came to be. I asked him. I bought all of the mica caps from Mouser.
Leonard
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I had my WA2EBY toroids wound for me by the same guy who does the toroid sets for Elecraft, to Elecraft's approved standards. I am waiting for the rest of the parts to arrive from Mouser, with the exception of the SMD resistors, which are on order from China. The ones from Mouser are on back-order, and won't arrive until NOVEMBER (!), and I really don't want to wait quite that long...
Rich KC8MWG
On Friday, July 7, 2017, 9:04:32 PM EDT, Jack Purdum via Groups.Io <econjack@...> wrote:
Diz's company, Kits And Parts, is a gold mine for hard-to-find caps and toroids. A friend of mine has one of his One Watters and it's a fun little rig. Keep him in mind when you're building.
Jack, W8TEE
From: Leonard <dredger@...> To: [email protected] Sent: Friday, July 7, 2017 8:23 PM Subject: Re: [BITX20] 80m hexfet power amplifier by W7ZOI
"Yeah, I forgot about Diz. He's good. He also has a toroid kit for the
WA2EBY LPF assembly, but not a cap kit as far as I know...
john
AD5YE"
Diz might put together a mica cap kit for the wa2eby amplifier. Someone would have to ask him. That's how the toroid kit came to be. I asked him. I bought all of the mica caps from Mouser.
Leonard
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Dear Farhan,
I'm now building the PA but I'm in doubt about the two unmarked capacitors at each side of the input attenuator, should I use 0.1uF each? Thanks. Dan, HK4DEI
On Fri, Jul 7, 2017 at 9:07 PM, Richard Andrew Knack via Groups.Io <ihc73scout2@...> wrote: I had my WA2EBY toroids wound for me by the same guy who does the toroid sets for Elecraft, to Elecraft's approved standards. I am waiting for the rest of the parts to arrive from Mouser, with the exception of the SMD resistors, which are on order from China. The ones from Mouser are on back-order, and won't arrive until NOVEMBER (!), and I really don't want to wait quite that long...
Rich KC8MWG
On Friday, July 7, 2017, 9:04:32 PM EDT, Jack Purdum via Groups.Io <econjack= [email protected]> wrote:
Diz's company, Kits And Parts, is a gold mine for hard-to-find caps and toroids. A friend of mine has one of his One Watters and it's a fun little rig. Keep him in mind when you're building.
Jack, W8TEE
From: Leonard < dredger@...> To: [email protected] Sent: Friday, July 7, 2017 8:23 PM Subject: Re: [BITX20] 80m hexfet power amplifier by W7ZOI
"Yeah, I forgot about Diz. He's good. He also has a toroid kit for the
WA2EBY LPF assembly, but not a cap kit as far as I know...
john
AD5YE"
Diz might put together a mica cap kit for the wa2eby amplifier. Someone would have to ask him. That's how the toroid kit came to be. I asked him. I bought all of the mica caps from Mouser.
Leonard
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Dan.,? I would be very concerned about using it without redesign for SSB use.? That diode to? the gate of the Mosfet is designed to be pumped low and keep the gate off during part of the cycle.? This is used on class C amps to improve efficiency.? What is the positive bias for - well that is an offset.? And note that that later bias is not stabilised 5V with a resistive divider as normally used.? The use of the Qsk receive cct at RH side again indicates it is intended for class C use . I followed the link but it is presented there as just a circuit with no palaver about the design intent.? the two band RF amp that AF presented elsewhere in the blog has a lot more going for it.? ?Suggestion ; look this beast up?
FQP13N10 Single Nch Power MosFET ID 12.8A, VDS 100v TO220? ? .? It does have higher input capacitance the IRF 510 but it seems to perform well at RF.? The? current rating is twice that of the IRF510.? ?It is commonly available on EBay.
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Dan,
Bad choice unless you plan only CW.? That design was never for SSB.
Allison
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I really like the 40/20 design posted by back in 2017.?
I may be missing something, but I don't see any specifications on the filter toroids other than inductance. Are additional specs available?
Thanks and 73
Paul K2AYZ
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Sorry for the Noob question, but why would you go from a class AB push/pull PA to a single linear biased device and expect more power?? Could you not just increase the PA supply voltage on the uBitx finals to get the same result???
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Paul,
LPF inductors are normally wound on powdered iron toroids.? Either type 6 or 2 would do, as long as you attain the proper inductance.? You can use the calculator on toroids.info for that.? For this power level, 1/2" or larger size would be needed.
Evan,
The original poster was intending to use this amp on other rigs.
Daniel,
As noted before, the design you posted is for CW not SSB.? For moving to other bands, not just the LPF would need to be changed, but also the frequency trap on the receive side.
73,
Mark.
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Leonard
Paul Galburt - K2AYZ