More comprehensive Schematic by KD4SGE & WA4ITD

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DL2MAN
 

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More comprehensive Schematic by KD4SGE & WA4ITD

Post by DL2MAN »

It´s not just a schematic, drawn by electronics professionals, it also shares some other useful information in only one document.
Thanks to KD4SGE & WA4ITD for their work and thanks for sharing it with us:

*03. August 2022* Updated Version
https://dl2man.de/wp-content/uploads/20 ... _v1.0m.pdf

Since forum software is restricting maximum file size, I uploaded it to my main page and shared the link.

73 Manuel; DL2MAN
wa2t
 

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Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by wa2t »

Glad to see this work endorsed, good job Manuel!

73,

Robert, WA2T
myshanks
 

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Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by myshanks »

Great Manuel, superb work

VU2SPK
Shanks
India
73's
de
VU2SPK
Mysore India
Ohwenzelph
 

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Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by Ohwenzelph »

When I try https://www.youtube.com/watch?v=jlmurYa7SOg I get "no longer available"
I remember a video that showed the piezoelectric effect that tapping the caps had on the audio but was there a video about a mod that cured that?
Thanks
DL2MAN
 

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Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by DL2MAN »

Ohwenzelph wrote: 17 Aug 2022, 09:41 When I try https://www.youtube.com/watch?v=jlmurYa7SOg I get "no longer available"
I remember a video that showed the piezoelectric effect that tapping the caps had on the audio but was there a video about a mod that cured that?
Thanks
Video was not by me.... And I documented a possible fix here in the forum:
viewtopic.php?p=2863#p2863
The 0803 Tantalums helped, but were very hard to replace.
The linked 470nF 0603 Tantalums are a drop in replacement and greatly reduce microphonics effect.
Watch for polarity ;)

73 Manuel; DL2MAN
Ohwenzelph
 

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Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by Ohwenzelph »

How closely should the 470nF C25-28 caps be matched to keep the two sides of the Tayloe detector tightly balanced? I ask because the 0603 tants are 10% tolerance. And pricey if getting a bunch. Tnx

P.S. on the enhanced schematic, main board, page 2, the values for C24 and C30 are listed as 100n but should be 1n
RichardB
 

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Joined: 15 May 2022, 01:37

Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by RichardB »

Ohwenzelph, thanks for the feedback. I am in the process of correcting a few other goofs and expanding on the schematics to include separate RF board schematics for the new Classic and Lo band options.

As for the 470nF and tolerance: The capacitors are part of an RC filter. A 10% change in capacitance will cause a 10% change in the detector bandwidth. If the capacitors vary from each other by 10% you will get a distortion at the edge of the detected bandwidth. So using +/-10% capacitors will affect the audio bandwidth by +/-10%. A rough calculation of the (tr)uSDX bandwidth based on 50ohms and 470nF suggests a bandwidth of 3.38kHz +/- the tolerance of the capacitors used. And since the tolerance was not specified in the main board BOM, it can be assumed that 10% will be fine.

If you are interested in learning more about the Tayloe Detector:
Dan Tayloe wrote a paper on the detector:
http://www.norcalqrp.org/files/Tayloe_mixer_x3a.pdf

And a theses paper by Zenaneh Kebede provides a more in-depth view

https://researchrepository.wvu.edu/cgi/ ... ontext=etd

73
Richard, KD4SGE
VA3HF
 

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Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by VA3HF »

Is C44 in the 60m filter supposed to be 220p instead of 470p? Original schematic has it as 220p.
Tobias3001
 

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Joined: 06 Jun 2023, 18:04

Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by Tobias3001 »

Hi Guys,

The schematic is a really nice drawing and perfect documentation. Many thanks to the author.

How about the Software Defined Radio. Is there a similar document with block diagram available? That helps to understand the remaining part of the radio, e.g. TX modulation.

Best
Tobias
Ohwenzelph
 

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Joined: 01 Jan 2022, 03:47

Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by Ohwenzelph »

On the second page under “Taylor Quadrature Sampling Detector” what is labeled as C35, off pin 16 of U6, I believe, should be labeled C20.

(the actual C35 is on pin 16 of U5.)

73
rodo1
 

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Joined: 13 Jun 2023, 18:16

Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by rodo1 »

Hello,
On the schematic with the "classic" band LPFs, in the 20m filter L31 is labeled 100nH with 9 turns. However L32 is labeled 144nH, at 6 turns. How can fewer turns yield more inductance? Also, in some of the other filters, 100nH is listed at 5 turns. All cores are listed as T37-2.
I suspect either the inductance values are after spreading/compressing the turns and then measuring, or L31 has a typo.
Any help?
Tnx
Bob WB0POQ
KA1FT
 

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Re: More comprehensive Schematic by KD4SGE & WA4ITD

Post by KA1FT »

The cores for 20m on the classic board should be T37-6 yellow cores, not -2 reds. That's clearly an error. The -2s are only spec'd up to 10mhz (30m). They will work at higher frequencies but at reduced performance. I suspect the other items you mentioned are also typos.
73
KA1FT
Brian
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