Re: AGC Circuit for uBITX Featured in July 2019 QST Magazine
All caps have a rated voltage. That is the max voltage you apply to it. If you exceed this voltage the insulation between the "plates" of the cap will break down and the magical smoke will be released out of it. It will blow. Alliminium? caps are very sensitive to this max voltage. Therefore the max voltages are printed on them so you are can be aware of it. And the circuit designer also jods it down on the cct diagram. If your supply voltage is say 12V, it is safe to use a 16V rated cap. You do then have a safety margin for 'n slight mishap in the supply voltage if it occur. The cap will only charge up to the supply voltage. So using a higher voltage rated cap will make no difference. The cap can not generate a higher voltage than what is supplied to it. Your safety margin will just be greater. Using a 50V cap in a 12V system ? So what. The capacitance of the cap is worth watching and to adhere to. Also the voltage rating of the cap determines its fiscall? dimensions.? J van der Merwe
On Mon, 12 Aug 2019, 12:21 David Wilcox via Groups.Io <Djwilcox01= [email protected]> wrote: Can someone explain the reasons for certain voltages listed on any schematic for the electrolytic caps, AND what problems could arise if one used a cap with a larger voltage rating? How much higher a voltage cap could be substituted without causing a problem?
Dave K8WPE? David J. Wilcox K8WPE¡¯s iPad Since the entire circuit set is 12V or less, your 16V caps should work just fine. ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Rob French (KC4UPR)
Sent: Monday, August 12, 2019 12:40 AM
To: [email protected]
Subject: Re: [BITX20] AGC Circuit for uBITX Featured in July 2019 QST Magazine ? Thanks.? Any thoughts on voltage rating for the capacitors, especially the "big" electrolytic ones?? (10uF, 100uF, 470uF... I'm assuming they're electrolytics.)? I looked at the Hycas schematic, and that calls out 50v for all the caps, but I don't have many of those... got lots of 16v though! -- ¡_. _._
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Re: Antuino now available for purchase
One other question. Can the 10 MHz output be used as a frequency source for calibration purposes?
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Re: Antuino now available for purchase
Thanks. I had already ordered it and saw the video of it not in a case. Now I can sell my MFJ-259.?
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Re: Antuino now available for purchase
It is a fully tested unit in the all metal case. It has an internal battery case for 6 AA cells. Two SMA connectors.
Does it come with the case?
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Re: Antuino now available for purchase
Does it come with the case?
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Re: AGC Circuit for uBITX Featured in July 2019 QST Magazine
The voltage rating on the capacitor is the maximum the component can ¡°deal with¡±. It works absolutely fine at lower voltages of course and it is best to give some headroom for example on a 12v rail,use 16v capacitors.
There is no problem going up to say 25 or higher voltage rating,just expect a physically larger component which might not fit in the desired space.
Electrolytics are happiest when run at 50%? and above of their stated voltage, they tend to deteriorate if say a 100v component is used on a 12v rail. The low voltage in comparison to their rating does not properly keep the component and
its chemicals in proper balance.
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This is why equipment not used for some considerable time needs careful powering up because of the deterioration of electrolytics deprived of polarising voltage.
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For a 12v DC ?rail use 16v or 25v components.
?
Hope this helps
?
Ian M0IDR
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Sent from for Windows 10
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Can someone explain the reasons for certain voltages listed on any schematic for the electrolytic caps, AND what problems could arise if one used a cap with a larger voltage rating? How much higher a voltage cap could be substituted without causing a problem?
Dave K8WPE?
David J. Wilcox K8WPE¡¯s iPad
Since the entire circuit set is 12V or less, your 16V caps should work just fine.
?
?
From:
[email protected] [mailto:[email protected]]
On Behalf Of Rob French (KC4UPR)
Sent: Monday, August 12, 2019 12:40 AM
To: [email protected]
Subject: Re: [BITX20] AGC Circuit for uBITX Featured in July 2019 QST Magazine
?
Thanks.? Any thoughts on voltage rating for the capacitors, especially the "big" electrolytic ones?? (10uF, 100uF, 470uF... I'm assuming they're electrolytics.)? I looked at the Hycas schematic, and that calls out 50v for all the caps,
but I don't have many of those... got lots of 16v though!
--
¡_. _._
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Re: AGC Circuit for uBITX Featured in July 2019 QST Magazine
Can someone explain the reasons for certain voltages listed on any schematic for the electrolytic caps, AND what problems could arise if one used a cap with a larger voltage rating? How much higher a voltage cap could be substituted without causing a problem?
Dave K8WPE? David J. Wilcox K8WPE¡¯s iPad
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On Aug 12, 2019, at 2:18 AM, MadRadioModder < madradiomodder@...> wrote: Since the entire circuit set is 12V or less, your 16V caps should work just fine. ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Rob French (KC4UPR)
Sent: Monday, August 12, 2019 12:40 AM
To: [email protected]
Subject: Re: [BITX20] AGC Circuit for uBITX Featured in July 2019 QST Magazine ? Thanks.? Any thoughts on voltage rating for the capacitors, especially the "big" electrolytic ones?? (10uF, 100uF, 470uF... I'm assuming they're electrolytics.)? I looked at the Hycas schematic, and that calls out 50v for all the caps, but I don't have many of those... got lots of 16v though! -- ¡_. _._
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Re: Antuino now available for purchase
Good news. Everyone has been waiting. Thank you.
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Antuino now available for purchase
Good work Ashar!
http://www.hfsignals.com/index.php/antuino/
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Re: AGC Circuit for uBITX Featured in July 2019 QST Magazine
Since the entire circuit set is 12V or less, your 16V caps should work just fine. ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Rob French (KC4UPR)
Sent: Monday, August 12, 2019 12:40 AM
To: [email protected]
Subject: Re: [BITX20] AGC Circuit for uBITX Featured in July 2019 QST Magazine ? Thanks.? Any thoughts on voltage rating for the capacitors, especially the "big" electrolytic ones?? (10uF, 100uF, 470uF... I'm assuming they're electrolytics.)? I looked at the Hycas schematic, and that calls out 50v for all the caps, but I don't have many of those... got lots of 16v though! -- ¡_. _._
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Re: AGC Circuit for uBITX Featured in July 2019 QST Magazine
Thanks.? Any thoughts on voltage rating for the capacitors, especially the "big" electrolytic ones?? (10uF, 100uF, 470uF... I'm assuming they're electrolytics.)? I looked at the Hycas schematic, and that calls out 50v for all the caps, but I don't have many of those... got lots of 16v though!
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Re: AGC Circuit for uBITX Featured in July 2019 QST Magazine
As I recall, the JackAl AGC circuit is just the Hycas AGC circuit lifted from QST December 2007.? Al added a couple of things like a switch to turn it off.? The FETs are nothing special.? A 201 and a 102 will work fine. ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Rob French (KC4UPR)
Sent: Sunday, August 11, 2019 10:57 PM
To: [email protected]
Subject: Re: [BITX20] AGC Circuit for uBITX Featured in July 2019 QST Magazine ? I'm looking at possibly lifting just the AGC circuit out of the JackAl design, and seeing if I can stock it out of my junk box.? But... the only JFET's I have are MPF102, J201, 2N5486, and 2N4393... will any of those work?? Other than the MPF102, the rest were all originally purchased for audio work, so I can totally imagine them not being suitable.
Thanks!
-Rob -- ¡_. _._
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Re: uBitx and QCX review in QST August 2019
I agree: the video was nice, but lacking. Many very basic facts were left out. Seemed to be aimed at hams who already knew about the uBitx and just wanted to see one.
-- Donald, KB5PWL
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Re: AGC Circuit for uBITX Featured in July 2019 QST Magazine
I'm looking at possibly lifting just the AGC circuit out of the JackAl design, and seeing if I can stock it out of my junk box.? But... the only JFET's I have are MPF102, J201, 2N5486, and 2N4393... will any of those work?? Other than the MPF102, the rest were all originally purchased for audio work, so I can totally imagine them not being suitable.
Thanks!
-Rob
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For transmitting CW, clk2 drives mixer d1/d2 at the transmit frequency.? The modulator, 2 crystal filters, and 2 IF amps are not used.?
When transmitting SSB, all of that stuff must work.
Jerry, KE7ER
On Sun, Aug 11, 2019 at 08:56 AM, Evan Hand wrote:
Dan's suggestion on CW as a test is the correct course.? It will verify if you have an RF or Audio issue.
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Re: uBitx and QCX review in QST August 2019
Asher,
You may wish to contact ARRL and ask permission to host a PDF of the review article on your own website.? I'm not sure what the arrangement is for that sort of thing, but I've encountered that several times.? For instance, Elecraft has PDFs of the various ARRL review articles of their equipment for free download on their site.
73,
-- Dave, N8SBE
-------- Original Message --------
Subject: Re: [BITX20] uBitx and QCX review in QST August 2019
From: "Matthew Pitts via "
< daywalker_blade_2004@...>
Date: Sun, August 11, 2019 1:41 pm
To: [email protected]
There are a lot of videos related to the uBitX on YouTube that can add details that are missing in the ARRL video. Matthew N8OHU On August 11, 2019 11:26:38 AM EDT, Robert McClements < gm4cid@...> wrote: ?Ken Hansen, yes, agreed,? the QST article does make these points.
The video will be seen by many who do not have access to QST and who are
not familiar with the uBitx and they will get??information about the product.
that is a very incomplete and potentially open to misinterpretation.
As I stated earlier, ARRL could have done much better, disappointing.
Bob GM4CID -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
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Re: VK4PP uBitx add-on Boards. (VK4PLN)
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Thanks Dan!
I appreciate the response.
I did lookup the mic wiring - that is where I started. ? Uniden BC-645 is a Cobra compatible electret 4 pin mic wiring 1-GND, 2-MIC, 3-PTT, 4-RX - I have 1, 2 and 3 wired correctly, I believe, per my enclosure instructions.??
Sadly - no 3.5mm plug at hand at the moment - but I will wire up the mic and PTT button that came with the kit and test.
Curious if anyone has experience with this mic.
Dean
KK4DAS
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Re: VK4PP uBitx add-on Boards. (VK4PLN)
Hi Everyone.
I have almost made it through the backlog of projects, so I should be able to start working on add-on boards again soon.
Cheers,
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Kobus ZS6CHK
Jim
MadRadioModder
Darrel H K0CXF
Nick VK4PP