Date   
Re: Questions about Bitx40

martin Fraser
 

I know my one uses Adafruit_TFTLCD.h and Adafruit_GFX.h but i will have to try next week when i am home 
the mcufriend Arduino library and see if it will work
it looks identical to this 
240x320 2.8" TFT Shield driver 4535 for Arduino : comments » Cee'z Blog

 

 
 

Re: Questions about Bitx40

Jack Purdum <econjack@...>
 

Hi Martin:

I have submitted an article based on the same VFO/TFT display to QST for publication...no word yet. It's actually an antenna analyzer, but the VFO and TFT work the same way. I'm also presenting a paper ("Giving Your QRP Rig a Face Lift.") at FDIM that adds the VFO/TFT display to the BITX40, so I need to wait to release that code. 

However, if your TFT display can use the mcufriend Arduino library, I'll write an interface demo program and post it so you can see how easy it is to do it.

72,
Jack, W8TEE



From: "riggerswa@... [BITX20]"
To: BITX20@...
Sent: Thursday, January 5, 2017 9:15 AM
Subject: [BITX20] Re: Questions about Bitx40

 
Jack can you share the coding with us please i have a tft at home begging for a vfo :)


regards Martin
VK6FEEE


Re: LED for XMIT indication

Roy Appleton
 

Pop, thanks for uploading the photo, I think adding the dual LED is a great idea. I wish I had a case like yours too! :-))

Roy
WA0YMH

On Jan 4, 2017 11:32 PM, "'VU2POP' vu2pop@... [BITX20]" <BITX20@...> wrote:
 

Hi ,

You may see the attached foto , zoom in to see the red & green wires soldered to the DIP relay points

Green for Rx and Red for Tx which is fed to the dual color LED ( three terminal type) the centre goes thru a 680 ohms resisitor to gnd.

happy homebrewing

best 73

Pop

VU2POP

 

From: BITX20@... [mailto:BITX20@...]
Sent: Thursday, January 05, 2017 8:49 AM
To: BITX20@...
Subject: [BITX20] Re: LED for XMIT indication

 

 

Well, I'm not sure photos would do, and it might take several. Plus there's 20 minutes of disassembly 

and re-assembly - it's screwed to the box...!

However if you look at the schematic - lower left: http://www.hfsigs.com/bitx40v3_circuit.png

... you'll see the PTT and the 'main' relay - Pins 1 and 3 are RX+12V and TX+12V, respectively.

They're even LABELLED on the schematic as RX and TX! They're not labelled on the PCB, but you

can even test this with a voltmeter. Pin 1 will be +12 during receive. PTT and it will drop and TX (Pin 3)

will pop up to +12.

 

Pick off your 'GREEN' and 'RED' anodes. Most Bicolor LEDs I've seen have a common cathode,

so that (center) wire is ground. 
You can pick up GROUND from this same relay - Pin 16 of the relay is ground. 

  
An even better picture can be seen from the 'wireup' page:  http://www.hfsigs.com/bitx40v3_wireup.html

 

The PTT Relay is right in front (and down a bit) from the PTT connector. PIN 1 is 'down' & 'right' (if you're

looking at the wireup.html page).


There's no need to desolder or remove the relay. Just go underneath and, strip your wires SHORT.
You just need like 3 or 4 mm. Just solder to where the relay socket pins are soldered (remember they're
'reversed' on the bottom) - Pin 1 - RX, Pin 2 - TX, Pin 16 (which is opposite from Pin1 - it's a 16-pin

socket) Pin 16 is ground. You can either run it to a connector and 'crazy glue' or hot-glue to the PCB

just underneath (and to the right of) the power connector - or, you can just run them in the free-air, maybe

use some shrink tubing to keep them together. Just run them to your Bicolor LED.

Hope that helps. 
Now - if I have some time this weekend, I'll snap some photos.

 

Mike Y

Re: Questions about Bitx40

martin Fraser
 

Jack can you share the coding with us please i have a tft at home begging for a vfo :)


regards Martin
VK6FEEE

Re: LED for XMIT indication

M Garza <mgarza896@...>
 

Paul,
I was going chime in with the same kind of suggestion.  Adding in a variable resistor, you could power a simple xmit meter.  A relay could be run off of the ptt switch to toggle it between s meter and output meter.
Just my plan, once my bitx arrives.

73s

Marco Garza  (KG5PRT)


On Jan 5, 2017 7:43 AM, "Paul Chebi paul.chebi@... [BITX20]" <BITX20@...> wrote:
 

In one of my earlier Bitx's I picked up by inducing into a couple of turns on on one of the final transformers/filters rectified it with a 1048 diode and fed it into an led with a resistor.similar to a "Peack Detector" circuit. This led will give you an indication of not only Xmit but a relative indication of the Transmitted power by the brightness of the led. My 2 cents.

Paul Chebi


Re: LED for XMIT indication

Paul Chebi
 

In one of my earlier Bitx's I picked up by inducing into a couple of turns on on one of the final transformers/filters rectified it with a 1048 diode and fed it into an led with a resistor.similar to a "Peack Detector" circuit. This led will give you an indication of not only Xmit but a relative indication of the Transmitted power by the brightness of the led. My 2 cents.

Paul Chebi

Re: Output stages voltage for reference

 

Jorge,

If you measure total current then you will not be able to reduce to zero. If you put a meter only to final stage then
the current control will be effective.

My board came with ~150mA in the final stage IRF.

Raj


At 05-01-2017, you wrote:
 

�  � Thanks Raj but I can not adjust the 50 mA at rest, something is wrong yes!
�  �  Jorge

2017-01-04 13:47 GMT-02:00 Raj vu2zap@... [BITX20] <BITX20@... >:
� 

Jorge,

This is normal. As the final IRF warms up the current increases. Do not worry!

At 04-01-2017, you wrote:
� 

�  �  Hello Raj, my BITX20 V3 Linear is consuming 155mA I think a lot, what will be happening? Maybe the auto FET flickering?
�  �  Â Jorge PY2PVT _._

2017-01-04 10:11 GMT-02:00 Raj vu2zap@... [BITX20] <BITX20@... >:
� 
For anyone trouble shooting the final stages.
Measured these voltages without any modulation
Power supply exact 12V, PTT pressed/shorted
Predriver Q13 drawing 30mA
C=11.6
B=3.66
E=3.0
Driver Q14 drawing 41mA
C=11.85
B=1.0
E=0.415
Final Q15 drawing 150mA
C=12
G=4V
E=0




--
�  73 de Jorge PY2PVT
�  Campinas SP
�  GG67MD




--
�  73 de Jorge PY2PVT
�  Campinas SP
�  GG67MD

Re: Output stages voltage for reference

Jorge Luiz Fenerich
 

    Thanks Raj but I can not adjust the 50 mA at rest, something is wrong yes!
    Jorge

2017-01-04 13:47 GMT-02:00 Raj vu2zap@... [BITX20] <BITX20@...>:

 

Jorge,

This is normal. As the final IRF warms up the current increases. Do not worry!

At 04-01-2017, you wrote:

 

    Hello Raj, my BITX20 V3 Linear is consuming 155mA I think a lot, what will be happening? Maybe the auto FET flickering?
     Jorge PY2PVT _._

2017-01-04 10:11 GMT-02:00 Raj vu2zap@... [BITX20] <BITX20@... >:
 

For anyone trouble shooting the final stages.

Measured these voltages without any modulation

Power supply exact 12V, PTT pressed/shorted

Predriver Q13 drawing 30mA
C=11.6
B=3.66
E=3.0

Driver Q14 drawing 41mA
C=11.85
B=1.0
E=0.415

Final Q15 drawing 150mA
C=12
G=4V
E=0




--
  73 de Jorge PY2PVT
  Campinas SP
  GG67MD




--
  73 de Jorge PY2PVT
  Campinas SP
  GG67MD

New Bitx40v3-2

 

Received the new version.

The trifilar toroids are mounted on PCB support formers - nice touch!

Board was nicely bubble wrapped.

The raduino regulator was bent a little to one side. No other issues.

73

--
Raj, vu2zap
Bengaluru, South India.

Re: the arrival

 

Mark,

Me too, same day, haven't heard a thing.

Joel Caulkins
KB6QVI

On Jan 4, 2017, at 9:27 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote:

 

I ordered the upgrade on 12/23 and haven’t heard a thing yet.

Mark

K3MRK

 

 

From: BITX20@... [mailto:BITX20@...]
Sent: Wednesday, January 04, 2017 6:42 PM
To: 'BITX20@...'
Subject: RE: [BITX20] the arrival

 

 

December 16th. Waiting to here back…the potentiometer for the balanced modulator is missing…not sure if this is just a redesign. Mine came without the Raduino.

Billy Shepherd
Bartholomew Co 911 Center
131 S Cherry St.
Columbus, IN 47201

From: BITX20@... [mailto:BITX20@...]
Sent: Wednesday, January 04, 2017 5:52 PM
To: BITX20@...
Subject: Re: [BITX20] the arrival


Great! What date did you order it?

Rich
KC8MWG

On Wednesday, January 4, 2017 2:13 PM, "Billy Shepherd billy.shepherd@... [BITX20]" <BITX20@...> wro te:


2 weeks to ship for free from India to Indiana, awesome!
[][]
[]

[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]

Re: BITX40: how to order seperate DDS?

Ton
 

Thanks for your quick response Cor, I will send a mail this evening.


73' Ton PA1PXL

Re: It stopped transmitting

Ashhar Farhan
 

l think the best way is to change the emitter bias.
- f

On 05-Jan-2017 1:54 pm, "'Soundararajan Ra.' vu2rjw@... [BITX20]" <BITX20@...> wrote:
 

As Ft is 300 Mhz maximum gain possible is 300/7=43 the same gain can be get at 10 ma with 3904 .where as if we use 2n22222a  for same  gain 150ma is required .
About bc 48 series ft is to be taken as minimum 150 mhz max 300 mhz may not be suitable. 
we may change R132 to 180 ohms so that current wille be 3.1/180=17 ma

soundar VU2RJW


On Thu, Jan 5, 2017 at 12:19 PM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:
 

Jerry,

My Q13 is running uncomfortably hot. The static dissipation without RF is greater than the rated 225mW.
Farhan is aware of this and a change of one or two resistors are in order.

Cheers
Raj vu2zap


At 05-01-2017, you wrote:

 

I think John may have nailed it.

Quiescent voltage at the emitter of Q13 is around 3.1 volts, so current is 3.1v/100ohms = 31ma, which is ok
Quiescent power dissipation is (12-3.1)*.031 = 276 mW, which is an awful lot for a Sot23 package.

If mine blew, I'd replace it with something in a bigger package capable of dissipating the heat.
A 2n3904 in the standard TO-92 through hole, or perhaps even better in the Sot-223 that Fairchild has.
A 2n2222a could work too if that's what you got.

When hacking in a leaded part, I'd just solder the legs to the nearby R's and C's rather than try to use the Sot23 pads.

Alternately, might be able to adjust that 100 ohm emitter resistor as John suggested, to maybe 150 ohms.  I'm not sure how that would impact performance here.

Jerry, KE7ER


---In BITX20@..., wrote :
Note that you still haven't figured out what caused the problem in the first place. It may be that there is too much current flowing through the transistor and the emitter resistor may have to be adjusted. This can happen with too long a hold on the PTT. Maybe a heavier transistor is called for...


Re: BITX40: how to order seperate DDS?

Cor Beijersbergen
 

You can place a request  at hfsignals.gmail.com. Mention the serial number of your BITX40 and you will probably get a notification to pay 14$ via Paypal. At least that worked for me.

 

Cor PA4Q

 

 

As one of the earlier owner of this nice BITX40, i have the analoge version while DDS was not available at that time. Now i wonder if one can order the DDS to complete the BITX40.

If yes, how??

Re: BITX40: how to order seperate DDS?

William R Maxwell
 

I have just ordered one by emailing hfsignals(at)gmail.com. earlier emails to the shorter form hfsigs@... went unanswered. $14 USD.

Bill, VK7MX


On 5/01/2017 7:23 PM, tonrijnen@... [BITX20] wrote:
 

As one of the earlier owner of this nice BITX40, i have the analoge version while DDS was not available at that time. Now i wonder if one can order the DDS to complete the BITX40.

If yes, how??


Re: Si5351 VFO - Low Pass?

Mvs Sarma <mvs_sarma@...>
 

After all we have  band pass filter and crystal filter (for LSB /USB) after the mixer to take care of unwanted. we also have a Low pass filter to cut off harmonics possibly created by Lin PA.
Best of 2017

sarma
 vu3zmv
 


On Thursday, 5 January 2017 9:16 AM, "Baruch Atta baruchatta@... [BITX20]" wrote:


 
I thought that a pure sine wave was best. Isn't a square wave a mix of waves?  That would result in all sorts birdies and products?

On Jan 4, 2017 10:28 PM, "Ken Chase chase8043@... [BITX20]" <BITX20@...> wrote:
 
And I am using the Adafruit SI5351.

73 Ken

On Wed, Jan 4, 2017 at 10:26 PM, Joel Caulkins caulktel@... [BITX20] <BITX20@...> wrote:
 
Jerry,

Im using the Etherkit Si5351 breakout board. https://www.etherkit.co m/rf-modules/si5351a-breakout- board.html

Joel KB6QVI

On Jan 4, 2017, at 7:08 PM, jgaffke@... [BITX20] <BITX20@...> wrote:

 
I'm no RF guru, but had thought a diode ring mixer would be fine with a square wave LO.
Would be interesting to hack the analog VFO to give a square wave at the same amplitude as the Si5351, see if that has similar rx noise.  Might be other things going on here, like uC hash or a poor board layout.
Curious how the softrock guys found it necessary to have galvanic isolation for their Si570.

I assume nobody in the field yet has a Raduino equipped Bitx40 to experiment with.
What Si5351 board are you using?

Jerry, KE7ER

On Wed, Jan 4, 2017 at 8:26 PM, Joel Caulkins caulktel@...  wrote: 
 Mine was noisier too until I put a LPF inline with the Si5351. 



Re: It stopped transmitting

Soundararajan Ra.
 

As Ft is 300 Mhz maximum gain possible is 300/7=43 the same gain can be get at 10 ma with 3904 .where as if we use 2n22222a  for same  gain 150ma is required .
About bc 48 series ft is to be taken as minimum 150 mhz max 300 mhz may not be suitable. 
we may change R132 to 180 ohms so that current wille be 3.1/180=17 ma

soundar VU2RJW


On Thu, Jan 5, 2017 at 12:19 PM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:
 

Jerry,

My Q13 is running uncomfortably hot. The static dissipation without RF is greater than the rated 225mW.
Farhan is aware of this and a change of one or two resistors are in order.

Cheers
Raj vu2zap


At 05-01-2017, you wrote:

 

I think John may have nailed it.

Quiescent voltage at the emitter of Q13 is around 3.1 volts, so current is 3.1v/100ohms = 31ma, which is ok
Quiescent power dissipation is (12-3.1)*.031 = 276 mW, which is an awful lot for a Sot23 package.

If mine blew, I'd replace it with something in a bigger package capable of dissipating the heat.
A 2n3904 in the standard TO-92 through hole, or perhaps even better in the Sot-223 that Fairchild has.
A 2n2222a could work too if that's what you got.

When hacking in a leaded part, I'd just solder the legs to the nearby R's and C's rather than try to use the Sot23 pads.

Alternately, might be able to adjust that 100 ohm emitter resistor as John suggested, to maybe 150 ohms.  I'm not sure how that would impact performance here.

Jerry, KE7ER


---In BITX20@..., <iam74@...> wrote :
Note that you still haven't figured out what caused the problem in the first place. It may be that there is too much current flowing through the transistor and the emitter resistor may have to be adjusted. This can happen with too long a hold on the PTT. Maybe a heavier transistor is called for...


BITX40: how to order seperate DDS?

Ton
 

As one of the earlier owner of this nice BITX40, i have the analoge version while DDS was not available at that time. Now i wonder if one can order the DDS to complete the BITX40.

If yes, how??

Re: Si5351 VFO - Low Pass?

alf
 

Just another thing to keep in mind, with the stock vfo 4.8 to 5.00 MHz, 30 times the vfo frequency will produce birdies in the 2 metre band, a case for using a metal enclosure, pardon the pun.

Alf vk2yac

iam74@... [BITX20] wrote:


A diode ring mixer is inherently a non-linear device. Look at the voltage curves for diodes and you will see that there is a floor near the inverse voltage that guarantees that there will be never be instantaneous transition from positive to negative at zero volts (the ideal).

One uses diode ring mixers because they have an immense dynamic range compared to others.

That being said, one must pay attention to the frequencies one feeds into the mixer. There will always be birdies. One must plan on them being outside of the bands being used so that they are not a problem. Figuring out mixer products to the 4th or 5th harmonic on a spreadsheet is very helpful. There will also always be some IMD. But planning proper impedance matching and filtering will always make it tolerable (i.e., down 40 dB or more).

So it doesn't matter whether or not one feeds a square wave or sine wave. (The square wave is more or less preferred as it more easily saturates the diodes). There are inherent problems which must be addressed. The thing that really matters is the level of input signal and where are the gozintas and gozouttas. The RF must be clean and be capable of 140 dB or so gain level. The LO should be around 7 dbM. The IF must be impedance matched and able to take care of reflected waves. SWR is important; most of the noise and distortion products come from improper feedback from the IF; there have been all sorts of solutions to that problem (especially diplexers).

Still, unless they are very noticeable, most ears can adjust fairly quickly to some level of noise and it is not really a problem --
especially with noisy amplifiers surrounding the mixers...


The BITX solution is quite simple: provide a IF from the mixer that guarantees no in-band birdies, and provide broadband amplifiers around it which minimize reflection back into it. Along with a good ladder filter (the same is true there) It works fairly well. There have been some mods done, most prominently the LC filter on transmit of the BITXxxA series. You may find some to be necessary to conform to the transmit laws of your country.

If I were to provide a filter on the DDS into the mixer, I would consider some sort of low Q LC filter, which is really a variant of a diplexer. But it is probably overkill if the input level is right AND it is fed into the proper terminal.

john
AD5YE


---In BITX20@..., <jgaffke@...> wrote :

With a diode ring mixer, those diodes are pretty much either conducting or not conducting. So the action of the mixer is a square wave, even if you feed it a nice clean sine wave.

Given the balanced nature of the mixer, the narrow band crystal filter, and the band pass filter on the other side out toward the antenna, all those birdies should never come up. And these guys are talking broadband noise, not birdies.

Not that I know anything for sure here.

Jerry

---In BITX20@..., <baruchatta@...> wrote :

I thought that a pure sine wave was best. Isn't a square wave a mix of waves? That would result in all sorts birdies and products?

Re: Si5351 VFO - Low Pass?

Hans Summers
 

Hi all

I have to add some comments here.

1) You cannot see or measure phase noise on an oscilloscope. You cannot even see or certainly, not accurately measure, phase noise on a spectrum analyser, unless it's a really excellent one. Phase noise is rather difficult to measure!

2) The phase noise of an Si5351A Synthesiser is certainly very much less than that of the analogue VCO/VFO in the BITX40 or any other analogue VFO. Yes the phase noise of an Si5351A is not as good as a crystal oscillator. But it is sure that if you replace the analogue VFO of your BITX40 with an Si5351A Synth or a DDS, and IF you notice an increase in noise, then that is NOT due to phase noise. There must be some other culprit. 

3) Gywn G3ZIL did an interesting and thorough comparison of the QRP Labs Si5351A Synth module http://qrp-labs.com/synth with a crystal oscillator LO in a low noise direct conversion receiver. You can read his write-up here http://qrp-labs.com/synth/synthnoise.html . His conclusion was that the Si5351A noise was about 6dB worse than a well-designed crystal LO, and that 6dB would be of no consequence anyway relative to the background noise floor on HF. An analogue VFO would be much more than 6dB relative to a crystal.

4) The Si5351A libraries of Jason NT7S and Adafruit are both derived from the Linux Si5351A Driver. In my opinion what is fine for a powerful 32-bit processor is too bloated to use on an 8-bit system such as AVR, PIC and Arduinos. Furthermore the library caters for many possibilities, and also for the Si5351B and Si5351C variants, which makes it rather large and difficult to understand, particularly for non-expert coders. That's why I developed my own simplified Si5351A code. The QRP Labs website has several code examples, adapted for native AVR use, PIC, and Arduino environments. Of course these libraries work on the QRP Labs Synth module, or Jason's Etherkits Si5351A module, or Adafruit's module. See:

5) The QRP Labs Synth module http://qrp-labs.com/synth differs from Adafruit and Etherkit modules in the following respects:
   a) It is a kit, using all through-hole components except for the Si5351A which is already soldered by the PCB factory.
   b) At $7.75 it is the lowest priced of these three modules
   c) It has a 2x 10-pin DIP pin header suitable for use in matrix board, breadboards etc. RF outputs are available on the header pins or you could fit SMA sockets. 
   d) There are pads for a 25MHz or 27MHz TCXO if you wish to replace the supplied 27MHz crystal with a TCXO
   e) The module was also designed to have the same footprint as the popular eBay AD9850 DDS module, and a somewhat similar pinout. The power pins match the AD9850 DDS, and the I2C bus pins are on the same pins as the AD9850 DDS module control pins. The 3 outputs of the Si5351A module are connected to header pins which match where the AD9850 DDS output some of its signals. Therefore in many applications the QRP Labs Si5351A module may be plugged in where an AD9850 DDS previously sat, and only the software needs to be changed to talk to the Si5351A.

73 Hans G0UPL


Re: LED for XMIT indication

William R Maxwell
 

That is nice looking case, Pop. Can you advise as to its source.

73

Bill, VK7MX


On 5/01/2017 4:32 PM, 'VU2POP' vu2pop@... [BITX20] wrote:
 

Hi ,

You may see the attached foto , zoom in to see the red & green wires soldered to the DIP relay points

Green for Rx and Red for Tx which is fed to the dual color LED ( three terminal type) the centre goes thru a 680 ohms resisitor to gnd.

happy homebrewing

best 73

Pop

VU2POP

 

From: BITX20@... [mailto:BITX20@...]
Sent: Thursday, January 05, 2017 8:49 AM
To: BITX20@...
Subject: [BITX20] Re: LED for XMIT indication

 

 

Well, I'm not sure photos would do, and it might take several. Plus there's 20 minutes of disassembly 

and re-assembly - it's screwed to the box...!

However if you look at the schematic - lower left: http://www.hfsigs.com/bitx40v3_circuit.png

... you'll see the PTT and the 'main' rel ay - Pins 1 and 3 are RX+12V and TX+12V, respectively.

They're even LABELLED on the schematic as RX and TX! They're not labelled on the PCB, but you

can even test this with a voltmeter. Pin 1 will be +12 during receive. PTT and it will drop and TX (Pin 3)

will pop up to +12.

 

Pick off your 'GREEN' and 'RED' anodes. Most Bicolor LEDs I've seen have a common cathode,

so that (center) wire is ground. 
You can pick up GROUND from this same relay - Pin 16 of the relay is ground. 

  
An even better picture can be seen from the 'wireup' page:  http://www.hfsigs.com/bitx40v3_wireup.html

 

The PTT Relay is right in front (and down a bit) from the PTT connector. PIN 1 is 'down' & 'right' (if you're

looking at the wireup.html page).


There's no need to desolder or remove the relay. Just go underneath and, strip your wires SHORT.
You just need like 3 or 4 mm. Just solder to where the relay socket pins are soldered (remember they're
'reversed' on the bottom) - Pin 1 - RX, Pin 2 - TX, Pin 16 (which is opposite from Pin1 - it's a 16-pin

socket) Pin 16 is ground. You can either run it to a connector and 'crazy glue' or hot-glue to the PCB

just underneath (and to the right of) the power connector - or, you can just run them in the free-air, maybe

use some shrink tubing to keep them together. Just run them to your Bicolor LED.

Hope that helps. 
Now - if I have some time this weekend, I'll snap some photos.

 

Mike Y