Date   
Re: [SPAM] Re: [BITX20] Higher voltage for Bitx40 Final

K9HZ <bill@...>
 

Did you re-bias the 510s when you changed the PA voltage?  If not, theoretically this could happen if the bias were set right on the edge of class “C” operation.

 

 

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

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email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Sunday, February 04, 2018 3:22 PM
To: BITX20@groups.io
Subject: [SPAM] Re: [BITX20] Higher voltage for Bitx40 Final

 

11.5v should be fine, make sure it is still 11.5 when PTT is pressed.
Quiescent IRF510 drain current changing somewhat as they get warm is normal

The drop from 6w to 4w when V+ to the IRF510's is bumped from 12v to 24v is very weird.
Have you tried simply switching the IRF510 V+ between the two with exactly the same setup, same instrumentation?
Hate to say it, but my first guess would be pilot error.

On Sun, Feb 4, 2018 at 01:10 pm, Vic WA4THR wrote:

Just finished building my BitX40 after playing with the circuit for a few weeks. Early tests on mine suggested that using the small booster I have and raising the PA voltage from around 14 to 24 did seem to increase the power by the square of the voltage ratio, so matching these experiences. Admittedly, I was trying to read this on a 450w dummy load meter, and yelling into the mic, s not very accurate. So this past weekend I did get a QRP wattmeter that could read 30w as full scale and get a better idea of how much I am increasing.

However, now when I apply 24v to the final the power output actually drops from 6w to 4w! The only significant cuircuit difference is that I am now running the other 2 power connections (main board and Raduino) through a 7812 regulator, and since it is not getting quite enough to regulate to 12v, it is delivering about 11.5v to those boards, which I assumed was just a bit safer. The voltage booster is not dropping voltage under load, so I am befuddled as to why the power actually drops when I apply the higher voltage. I did recheck the PA bias and raised it up closer to 100ma, but I notice it slowly increases from wherever it is set if I continue to hold the PTT. Any ideas? Perhaps I should short the input to the output of the little 7812 to see if that actually had an effect.

Re: RD16HHF1 in the uBITX #ubitx

Nick VK4PP
 

I just wanna be able to output 5-10w on 28mhz.... not 1w... My QTH is pretty remote and without "decent" power, I wont get any contacts on >7mhz...

Might have to seriously consider an FT817, but the price.... lol.

Re: RD16HHF1 in the uBITX #ubitx

Nick VK4PP
 

Or a Youkits TJ5A

Re: Toroids winding information #ubitx

 

Cesar,

When I get back to town and my bench I will check and tell you.

Raj


At 05/02/2018, you wrote:
Hi! I have checking with a magnifying loupe looking for broken copper tracks or any strange looking components. I have unsoldered and redone t11 and t10
[]
i have resoldered all bits that looked poor soldered

still no advance. I get 0.7amps when ptt but no power output.

inyecting 7.150 400mV on t10 before mounting the t10 showed some activity but i guess it shoukd be higher right Raj?

Re: RD16HHF1 in the uBITX #ubitx

K9HZ <bill@...>
 

Two RD16HHF1 parts replacing the 510’s will do that.

 

 

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

Like us on Facebook! facebook icon

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Nick VK4PLN
Sent: Sunday, February 04, 2018 10:06 PM
To: BITX20@groups.io
Subject: [SPAM] Re: [BITX20] RD16HHF1 in the uBITX #ubitx

 

I just wanna be able to output 5-10w on 28mhz.... not 1w... My QTH is pretty remote and without "decent" power, I wont get any contacts on >7mhz...

Might have to seriously consider an FT817, but the price.... lol.

UBITX - COLOUR TFT - ATMEGA - CONFIGURATION / CONNECTIVITY DIAGRAM #ubitx

Joe
 

See attached  diagram I use for connecting the Colour TFT and atmega to the UBITX


Joe
VE1BWV

Re: RD16HHF1 in the uBITX #ubitx

Nick VK4PP
 

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: RD16HHF1 in the uBITX #ubitx

John Backo
 

Ha! Re-designing the transformers is most of the tricky work. Yes; you will have to do that.
It might require some experimentation. Try to use FT-61 hog-nose material. I think it will be more
or less good for this application. FT-43 might work, but it will taper off at higher frequencies.

Keep the layout rather simple and try, if possible, to make it on a separate board with inputs and
outputs as far away from each other as possible. Some feedback mechanism between drain
and gate (or drain and ground) may be necessary. Simple attenuation impedance or transformer
matches should work for driving the gates, since the capacitance is quite low. Keep in mind the
WA2EBY layout and matching -- that should be a good guide.

I was thinking of setting the two output MOSFETS with 2N3866 drivers. Should put out about 10-14W
from 80m to 10m, with a drive of .5W or so...maybe less.

john
AD5YE

Re: RD16HHF1 in the uBITX #ubitx

Leland Lannoye
 

Bill: 

Sometime ago I read about a transistor that can handle a 65:1 SER. Do you know anything about the device?



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: K9HZ <bill@...>
Date: 2/4/18 23:25 (GMT-05:00)
To: BITX20@groups.io
Subject: Re: [BITX20] RD16HHF1 in the uBITX #ubitx

Two RD16HHF1 parts replacing the 510’s will do that.

 

 

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

Like us on Facebook! facebook icon

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Nick VK4PLN
Sent: Sunday, February 04, 2018 10:06 PM
To: BITX20@groups.io
Subject: [SPAM] Re: [BITX20] RD16HHF1 in the uBITX #ubitx

 

I just wanna be able to output 5-10w on 28mhz.... not 1w... My QTH is pretty remote and without "decent" power, I wont get any contacts on >7mhz...

Might have to seriously consider an FT817, but the price.... lol.

Re: LTSpice simulation of uBitx Power Amp

Jerry Gaffke
 

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: RD16HHF1 in the uBITX #ubitx

Jerry Gaffke
 

Impressive.
But what's an SER?
When I google "transistor SER" all I get is a bunch of Spanish language pages.


On Sun, Feb 4, 2018 at 09:06 pm, Leland Lannoye wrote:
Sometime ago I read about a transistor that can handle a 65:1 SER. Do you know anything about the device?
 

Re: RD16HHF1 in the uBITX #ubitx

Vince Vielhaber
 

He might be referring to the MRFE6VP61K25H/HS. Probably seen here: http://www.eham.net/ehamforum/smf/index.php?topic=75793.0

Vince.

On 02/05/2018 01:23 AM, Jerry Gaffke via Groups.Io wrote:
Impressive.
But what's an SER?
When I google "transistor SER" all I get is a bunch of Spanish language
pages.

On Sun, Feb 4, 2018 at 09:06 pm, Leland Lannoye wrote:

Sometime ago I read about a transistor that can handle a 65:1 SER.
Do you know anything about the device?


Re: LTSpice simulation of uBitx Power Amp

John Backo
 

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: LTSpice simulation of uBitx Power Amp

Jerry Gaffke
 


Hmmm,

I'm not assuming anything about drain loads, only that the load on the output of the transformer should be 50 ohms.
The LPF's on the uBitx and WA2EBY are symetrical, 50 ohms in and out, no impedance transformation there (at least for the fundamental).
Both amps are operating the IRF510's from a 24v supply, and the two drains of each amp
are bouncing about centered on 24vdc, out of phase.

The output should look very similar after we add in a low pass filter, 
though any harmonics will be knocked out to leave behind a clean sine wave.
 
Jerry


On Sun, Feb 4, 2018 at 10:53 pm, John Backo wrote:
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...

Re: RD16HHF1 in the uBITX #ubitx

Alex - PA1FOX
 


>PA1FOX has done this, but I don't think he has

>posted detailed results yet. (He has promised
>to do so).

>I have some, but have not gotten around to finding out what
>they do. It looks very good, though.

>john
>AD5YE

Yep, correct. I'm still here :)
View this link for the receiver in action so far.

I've been messing around with RD16HHF1 and it looks promising. Due to lack of time I have not been able to finish the tests yet, but 10 watts at 17m is easy.

They seem far more robust as well. During the test phase of the IRF's I blew up a couple of them, but the RD16HHF1 has already suffered from my experiments (wrong output impedance etc) but has survived all. The gain of the RD is much higher at the upper frequencies compared to the IRF, so I have encountered some oscillations if the bias is set too high. It's not a big problem to deal with that. The efficiency at 80m is better than with the IRF but still not so good as 30 to 17m. I'm still working on that. Need to play around with the binocular toroid.
I also still need to finish the low pass filter for 15-10m to see what it will do there. The output power at 17m gives hope for a good performance at the upper bands.

Illustrative picture so far. It's not finished yet :) 
Note the double crystal filter for SSB/wide CW and narrow CW at the bottom.



73, Alex
PA1FOX

Re: RD16HHF1 in the uBITX #ubitx

Lawrence Galea
 

On Mon, Feb 5, 2018 at 12:32 AM, Nick VK4PLN <nickpullen@...> wrote:
HI Group.
I have been searching and reading topics with regards to using the RD16HHF1 in the uBITX.
So far I have only been able to find suggesstions, but no actual implementations...

I was testing my uBITX and getting 9w on 40m but only 1W at 10m...
Would love to have 5w + higher up.

Can anyone provide more info/help?

Thanks.
73, Nick VK4PLN


Re: RD16HHF1 in the uBITX #ubitx

K9HZ <bill@...>
 

Nope. Close enough. 


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 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: Case

Sajeesh Pilakkat
 

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

Troubleshooting the #ubitx

César EA3IAV
 



As others, I am facing problems regarding tx on my #ubitx
First test I did without case showed no power on meter. I did not give importance to this then as I thought it was just an old uncalibrated meter.
then everything got complicated as I made some building mistakes but after all this messing around I am in the start point: no output 

i would be nice to have a troubleshooting video like on the bitx40

https://youtu.be/R8G8XAwq38A


Re: RD16HHF1 in the uBITX #ubitx

K9HZ <bill@...>
 

Well thats a loaded question.  Reflected power just means that the transistor must dissipate the power.  So at infinity SWR, the transistor(s) must be capable of dissipating all of it.  A 50 watt output radio with 50% overall efficiency needs to dissipate 50 watts in heat (input power 100 watts). So you work the problem backwards.  If i want 25 watts out (say PA is 40 % efficient) that means the total input power is 62.5 watts and 62.5-25= 37.5 must be dissipated in heat by the PA device... but that is at perfect SWR.  If the SWR is now 3:1, then since:



At Pf = 25, Pr would be 6.25 so the device needs to dissipate at least 37.5 watts from efficiency and another 6.25 watts in reflected power or 43.75 watts.  When I design TF amps, i use design such that you can transmit into a dead short (must take full reflected) and therefore the device(s) must be capable of dissipating full input power indefinitely. 


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 4, 2018, at 11:06 PM, Leland Lannoye <wa9aoe@...> wrote:

Bill: 

Sometime ago I read about a transistor that can handle a 65:1 SER. Do you know anything about the device?



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: K9HZ <bill@...>
Date: 2/4/18 23:25 (GMT-05:00)
Subject: Re: [BITX20] RD16HHF1 in the uBITX #ubitx

Two RD16HHF1 parts replacing the 510’s will do that.

 

 

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

Like us on Facebook! facebook icon

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Nick VK4PLN
Sent: Sunday, February 04, 2018 10:06 PM
To: BITX20@groups.io
Subject: [SPAM] Re: [BITX20] RD16HHF1 in the uBITX #ubitx

 

I just wanna be able to output 5-10w on 28mhz.... not 1w... My QTH is pretty remote and without "decent" power, I wont get any contacts on >7mhz...

Might have to seriously consider an FT817, but the price.... lol.