Date   
Re: LTSpice simulation of uBitx Power Amp

K9HZ <bill@...>
 

I have the .model for the RD series transistors if you care to run that too.  


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: www.VillaGrandPiton.com


email:  bill@...

 


On Feb 5, 2018, at 12:21 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

I've now uploaded an LTSpice simulation schematic file that allows easy comparison of the uBitx and WA2EBY finals,
also a pdf version for those who have not installed LTSpice:
    https://groups.io/g/BITX20/files/KE7ER/WA2EBYandUBITX.asc
    https://groups.io/g/BITX20/files/KE7ER/WA2EBYandUBITX.pdf

I haven't played with it too much, haven't taken any notes.
But here's what I think I'm seeing:

The WA2EBY does perform better. 
Power in is about the same between the two, power out from the WA2EBY is generally a factor of 3 greater.
The gates on the WA2EBY have nice sine waves, the uBitx is quite distorted there by capacitive loading.
Input impedance on both is about 50 ohms at 7mhz, both go down to about 12 ohms at 30mhz,
as determined by monitoring the voltage after the 50 ohm source impedance resistor.
Both show a 4x power increase when switching from 30mhz to 7mhz, more than I would
have expected on the WA2EBY, perhaps I have some wrong values on the inductors?
The IRF510 model assumes worst case for Rds(on) and Qgate, though I doubt that's just too far off.

Jerry, KE7ER

Re: LTSpice simulation of uBitx Power Amp

K9HZ <bill@...>
 

Dunno about that.  I always design my LP filters at 50:50 ohms in and out... and my PA transformers are 50 ohms at the output.  I don't know why you would want to make the LP filter a transform too?


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: www.VillaGrandPiton.com


email:  bill@...

 


On Feb 5, 2018, at 12:53 AM, John Backo <jabac@...> wrote:

Very good, Jerry.

However, note that the output is NOT 50 ohms until AFTER the LPF.
The input to the LPF is somewhat lower. And the WA2EBY has a voltage advantage
over the 12V input to the drains, though the output of the drains is closer to 50 ohms.

So it is a bit of a misnomer to assume that the drain load is 50 ohms. This is true, incidentally,
of any AB linear amplifier (and is probably one of the sources of oscillation). I should think that the
true drain load in this configuration is closer to 10 ohms than 50 ohms. The LPF transforms it
to 50 ohms for the antenna.

But it is not unreasonable to assume an overall load of 50 ohms. But be aware though, that one of the functions of
the LPF is to produce this. It is not quite true at the drains. The actual impedance at the drains is a function
of the first capacitor/inductance stage of the LPF. Things are not quite as simple as they seem...

john
AD5YE



Re: uBITX drive level.. #ubitx

Tilman D Thulesius
 

Hi 
Of course "decrease" means a smaller resistance.... The original R63 is 47ohms.
I cannot find 11ohms but 10 or 12 ohms in my supply....
/ Tilman

Re: Case

Vic WA4THR
 

I always enjoy seeing how others have built their BitX's and thought I'd point out some ideas I used with mine that others might find useful. For example:

1. Almost everyone places their tuning control to the right, but if you place the Raduino to the right you can easily update and play with the software by just plugging in to the USB port.

2. It is hard to beat the value of the Banggood instrument case. If you turn it upside down and eliminate attaching the hard plastic feet you have a smoother mounting surface for circuit boards and can use the vent holes for a speaker grille. I added some stick-on soft plastic feet on the "new" bottom.

3. While I still want to find a nice way to attach labels to the panel, using the second line of the BitX display is a convenient place to label switches and controls.

=Vic=
WA4THR

Re: Second batch of uBITX shipping? #ubitx

dj0hf
 

You couldn't make it up - My ubitx took just 24 hours to get from India to Germany with DHL and has now sat for 3 days (so far) at the customs in Leipzig and they are refusing to release it without a detailed description of exactly what is inside the package.
I've sent them a description and a link to the hfsignals web-site. So now it's just wait and see what happens. Maybe I'll get it eventually

Ian
DJ0HF/G3ULO

Re: Case

Jack, W8TEE
 

I agree:
Inline image

Jack, W8TEE



From: Vic WA4THR via Groups.Io <vhklein@...>
To: BITX20@groups.io
Sent: Monday, February 5, 2018 5:58 AM
Subject: Re: [BITX20] Case

I always enjoy seeing how others have built their BitX's and thought I'd point out some ideas I used with mine that others might find useful. For example:

1. Almost everyone places their tuning control to the right, but if you place the Raduino to the right you can easily update and play with the software by just plugging in to the USB port.

2. It is hard to beat the value of the Banggood instrument case. If you turn it upside down and eliminate attaching the hard plastic feet you have a smoother mounting surface for circuit boards and can use the vent holes for a speaker grille. I added some stick-on soft plastic feet on the "new" bottom.

3. While I still want to find a nice way to attach labels to the panel, using the second line of the BitX display is a convenient place to label switches and controls.

=Vic=
WA4THR



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Re: uBITX AGC - Adafruit TPA2016, A Success! #ubitx

bobolink
 

It’s a pretty complex device Data Sheet
i guess somebody could come up with device configuration for menu settings:
AGC fast, slow, data
That will work with the Bitx 
Placed an Adafruit on order.
tnx 

Re: Anyone (US Only for now) need a uBITX Raduino repaired? #ubitx

John Kemker
 

Hopefully, I won't need your service, Jim, but it's great to hear that you're willing to provide it!
--

73 de W5NNH

Re: uBITX AGC - Adafruit TPA2016, A Success! #ubitx

Art Olson
 

Nick

Did u post some code or did I miss your posting

73
Art -N2AJO 


On Feb 5, 2018, at 9:11 AM, rwhinric@... wrote:

It’s a pretty complex device Data Sheet
i guess somebody could come up with device configuration for menu settings:
AGC fast, slow, data
That will work with the Bitx 
Placed an Adafruit on order.
tnx 

Re: Case

pat griffin
 

Me too


Pat AA4PG



http://www.cahabatechnology.com


From: BITX20@groups.io <BITX20@groups.io> on behalf of Jack Purdum via Groups.Io <jjpurdum@...>
Sent: Monday, February 5, 2018 7:24:03 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Case
 
I agree:
Inline image

Jack, W8TEE



From: Vic WA4THR via Groups.Io <vhklein@...>
To: BITX20@groups.io
Sent: Monday, February 5, 2018 5:58 AM
Subject: Re: [BITX20] Case

I always enjoy seeing how others have built their BitX's and thought I'd point out some ideas I used with mine that others might find useful. For example:

1. Almost everyone places their tuning control to the right, but if you place the Raduino to the right you can easily update and play with the software by just plugging in to the USB port.

2. It is hard to beat the value of the Banggood instrument case. If you turn it upside down and eliminate attaching the hard plastic feet you have a smoother mounting surface for circuit boards and can use the vent holes for a speaker grille. I added some stick-on soft plastic feet on the "new" bottom.

3. While I still want to find a nice way to attach labels to the panel, using the second line of the BitX display is a convenient place to label switches and controls.

=Vic=
WA4THR



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Re: RD16HHF1 in the uBITX #ubitx

Jerry Gaffke
 

Curious.
Farhan recommends 100ma of bias through each uBitx FET, same as the Bitx40:
    http://www.hfsignals.com/index.php/ubitx-tuneup/
WA2EBY recommends 10ma in part2 of his writeup.

It does make sense on the Bitx40 to have a heavy quiescent current, since it is not push-pull.

You definitely want to zero the bias pots (RV2 and RV3 both clockwise on the uBitx)
before powering it up with new FET's, and then carefully adjust for the desired quiescent drain current.
Even if the new FET's are from the same lot as what was replaced, as the Vgs threshold 
can vary significantly from part to part.

Jerry, KE7ER




HFSingnals  bias current through each FET of 100ma can remain as it was on the uBitx.


On Mon, Feb 5, 2018 at 12:03 am, K9HZ wrote:
Nope. Close enough. 

  

On Feb 4, 2018, at 10:39 PM, Nick VK4PLN <nickpullen@...> wrote:

Excellent, thats what I am hoping to get to.
So the bias will need re-adjusting... Easy....?
What about the input and output transformers? I assume this will need modification due to the differnet impedances of the IRF and RD...

Thanks everyone for your input so far.
73.NIck VK4PLN

Re: uBITX AGC - Adafruit TPA2016, A Success! #ubitx

Michael Monteith
 

Which 2 boards?  I know the one is the TAP2016.  What's the other?

73, Michael
KM4OLT

On Fri, Feb 2, 2018 at 06:13 pm, Nick VK4PLN wrote:
Hi john, both boards from eBay...
I am really happy with the setup, AGC is performing very well in my opinion...

Re: uBITX drive level.. #ubitx

Anders Landgren
 

Mr Kang has published his fix for low drive on his excellent blog:
http://smallwonderqrp.blogspot.se/2017/11/?m=1
73 de SM5NNO

My UbitX and modify CW keying on Mic PTT #ubitx

Mitani Masaru
 

Hi,This is JE4SMQ masa.

My ubitx contains in ORIGAMI paper case(15 cm square).
It's costs only 100JPY(about $1).
Exchange no push switch Encoder and Indipendent push switch add.

Ver1.00R Software install and modify:

1. Transmit can Japan Amateur bands only.
If offband Frequency,no PTT/CW breakin work.
Thins function requre Japan low.
2.BAND Select mode,Frequency fits Japan BAND PLAN.
3.In CW mode.
Mic PTT can keying, This is Always,Straghit key mode.
If Paddle connect,keyer can use(in menu setting).

Thank you.

Re: Case

Arv Evans
 

Great looking chassis.  It shows what can be done with a small number of tools and
a lot of ingenuity. 

Arv  K7HKL
_._


On Mon, Feb 5, 2018 at 1:06 AM, Sajeesh Pilakkat via Groups.Io <sajeeshpilakkat@...> wrote:
Dear All,

Inviting you all to have a look on uBitx Case Home brewed.

http://vu3psz.blogspot.in/2018/02/ubitx-home-brewed-enclosure.html


Re: Second batch of uBITX shipping? #ubitx

Art Howard
 


On 5 Feb 2018 6:43 am, "dj0hf" <dj0hf@...> wrote:
You couldn't make it up - My ubitx took just 24 hours to get from India to Germany with DHL and has now sat for 3 days (so far) at the customs in Leipzig and they are refusing to release it without a detailed description of exactly what is inside the package.
I've sent them a description and a link to the hfsignals web-site. So now it's just wait and see what happens. Maybe I'll get it eventually

Ian
DJ0HF/G3ULO



Re: whistles in receive

Ashhar Farhan
 

The warm smells of an HRO steaming up... is there any hotroding one can do to these rigs?
- f

On 5 Feb 2018 12:02 am, "Leland Lannoye" <wa9aoe@...> wrote:
I am sitting here reading some of this information and studying the new technology.  When I was young (at leas 50 years ago), solid state technologies were either in their infancy or still a dream.  Our rigs were two pieces of equipment, a receiver and a transmitter with a variety of accessories.

Most of our receivers for those of us who were not well heeld in the financial area were of the single conversion genre with an if frequency of 455 kHz.  With little preselection capability, this relegated the ham bands 20 mtrs and above useless with hetrodyne images from frequencies 910 kHz either above or below the desired reception point. There, in that day, were three remedies to fix this. The first two were:

    1.)  add a really selective high gain preselector to tune the offending images out

    2.)  raise the if to something on the order of 1600 kHz which left bandpass selectivity at a substantial disadvantage.

The third option, and the most expensive in its day was double (or, even triple) conversion.  If  you were able to pay the 1958 price of over $300, you were in and there were few difficulties thereafter until the receiver aged and developed some bad shield grounds or worse.  The second or third conversion local oscillator would provide a cornu copia of birdies of one type or another. These included signals that were always there, I know the newer designs with balanced mixers and the like have few of these problems, but, it is worth considering.

An aging ham from way back.


Lee, WA9AOE


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Re: My UbitX and modify CW keying on Mic PTT #ubitx

Thomas Sharka
 

if (frequency >= 28000000 && frequency <= 28000000) hambandfrequyency = true

You can only transmit on 28 Mhz?
 


Sent from Yahoo Mail. Get the app


On Monday, February 5, 2018 10:28 AM, Mitani Masaru <mitani.masaru@...> wrote:


Hi,This is JE4SMQ masa.

My ubitx contains in ORIGAMI paper case(15 cm square).
It's costs  only 100JPY(about $1).
Exchange no push switch Encoder and Indipendent push switch add.

Ver1.00R Software install and modify:

1. Transmit can Japan Amateur bands only.
If offband Frequency,no PTT/CW breakin work.
Thins function requre Japan low.
2.BAND Select mode,Frequency fits Japan BAND PLAN.
3.In CW mode.
Mic PTT can keying, This is Always,Straghit key mode.
If Paddle connect,keyer can use(in menu setting).

Thank you.




Re: My UbitX and modify CW keying on Mic PTT #ubitx

Mitani Masaru
 

It's already fixed.
Thank you.

Re: whistles in receive

Leland Lannoye
 

There have been numerous articles in QST over the years on rebuilding these old rigs.  I found an article which I saved somewhere on building transistor substitutes for the tubes.  you could build them on small perf boards and set up a set of wires that corresponded to the pin out on the tubes.  At one time, someone was making modules to replace all the low power and receiving tubes on the Collins S line.  That was at least 40 years ago.  I don't do well on a lot of these tiny connections anymore due to age and aging eyes, but my history skills are still largely intact.

Lee, WA9AOE

PS: Still awaiting shipment on my Bitx.

On 2/5/2018 10:40 AM, Ashhar Farhan wrote:
The warm smells of an HRO steaming up... is there any hotroding one can do to these rigs?
- f

On 5 Feb 2018 12:02 am, "Leland Lannoye" <wa9aoe@...> wrote:
I am sitting here reading some of this information and studying the new technology.  When I was young (at leas 50 years ago), solid state technologies were either in their infancy or still a dream.  Our rigs were two pieces of equipment, a receiver and a transmitter with a variety of accessories.

Most of our receivers for those of us who were not well heeld in the financial area were of the single conversion genre with an if frequency of 455 kHz.  With little preselection capability, this relegated the ham bands 20 mtrs and above useless with hetrodyne images from frequencies 910 kHz either above or below the desired reception point. There, in that day, were three remedies to fix this. The first two were:

    1.)  add a really selective high gain preselector to tune the offending images out

    2.)  raise the if to something on the order of 1600 kHz which left bandpass selectivity at a substantial disadvantage.

The third option, and the most expensive in its day was double (or, even triple) conversion.  If  you were able to pay the 1958 price of over $300, you were in and there were few difficulties thereafter until the receiver aged and developed some bad shield grounds or worse.  The second or third conversion local oscillator would provide a cornu copia of birdies of one type or another. These included signals that were always there, I know the newer designs with balanced mixers and the like have few of these problems, but, it is worth considering.

An aging ham from way back.


Lee, WA9AOE


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