Date   
Re: antenna tuner for uBitx

ajparent1/KB1GMX
 

THe ZM-2, 4Sqrp, SLT, and L-tuner all work.

Personally the 4sqrp, L-tuner, SLT, and Elecraft T1 are in use here for power up to 10W
and do the job for multiple QRP radios.  For higher power I have a L-tuner I built that
easily takes 100W.  Those only get used for the inverted L and the 160M Inverted V
as all my other antennas are 50 ohm resonant as that saves losses though a tuner
and coax.

By far the best antenna is a matched one.  Second best is any needing a tuner.

Allison

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

R. Kuehn
 

Hi John,

Interesting simple design. You could probably get away without the isolator or extra SSR, just connect the base of a transistor to the op-amp output and you'd be good to go.

I went with a slightly more complex design after G4ILO, http://www.g4ilo.com/usblink.html, that rectifies the audio signal to turn on a transistor switch (schematic attached), however I could not get the base voltage on the transistor high enough to 'turn on the switch' so to speak. So after much fiddling and noodling I cheated and put in a comparator to drive the base of the transistor. 

There are many designs out there like a dual stage op-amp, from N1HFX, http://www.rason.org/Projects/basicvox/basicvox.htm, and another discrete transistor type from G8MNY, http://www.deserthound.com/amateur-radio/vox.html. If I would do it again I would go with the simpler version of the G8MNY as the final NPN will always be driven fully on when the vox is activated.

At some point I want to modify the bitx40 code to enable CAT but it is far down on my workbench list, and maybe someone will beat me to it ;^)

Ralph
N9WTX




On Tue, Mar 20, 2018 at 7:32 AM, John P <j.m.price@...> wrote:
As promised, I uploaded the description of the simple VOX interface between my PC and the BitX-40 that I've been using for FT-8. I suppose it will also work for other digital modes, and should really be able to work with almost any radio provided the PTT voltage & current don't exceed the specifications of the SSR I used.

Those of you who know me know that I'm a real hacker when it comes to hardware, so all suggestions for improvement are always welcome (email: my call at ARRL.net). Or post here so all can kibitz!

--
John - WA2FZW


Re: uBitx Component list

 

Ken, most of the SMD components are 1206 size.

Joel
N6ALT

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

Gordon Gibby
 

Locally, our design used a simple one transistor audio amplifier to properly develop a strong enough signal to be rectified and turn on a transistor switch to drive a relay.

We actually made our own circuit board for this.

We found that having the relay output dramatically reduced the amount of RF interference problems that we had.  Using a transistor output by itself resulted in rigs that would lock on.

Others have solved this problem with opto isolators.   

There are a lot of ways to get this to work.

Gordon 


On Mar 20, 2018, at 11:09, R. Kuehn <rekuehn@...> wrote:

Hi John,

Interesting simple design. You could probably get away without the isolator or extra SSR, just connect the base of a transistor to the op-amp output and you'd be good to go.

I went with a slightly more complex design after G4ILO, http://www.g4ilo.com/usblink.html, that rectifies the audio signal to turn on a transistor switch (schematic attached), however I could not get the base voltage on the transistor high enough to 'turn on the switch' so to speak. So after much fiddling and noodling I cheated and put in a comparator to drive the base of the transistor. 

There are many designs out there like a dual stage op-amp, from N1HFX, http://www.rason.org/Projects/basicvox/basicvox.htm, and another discrete transistor type from G8MNY, http://www.deserthound.com/amateur-radio/vox.html. If I would do it again I would go with the simpler version of the G8MNY as the final NPN will always be driven fully on when the vox is activated.

At some point I want to modify the bitx40 code to enable CAT but it is far down on my workbench list, and maybe someone will beat me to it ;^)

Ralph
N9WTX

<Screen Shot 2018-03-20 at 10.06.46 AM.png>


On Tue, Mar 20, 2018 at 7:32 AM, John P <j.m.price@...> wrote:
As promised, I uploaded the description of the simple VOX interface between my PC and the BitX-40 that I've been using for FT-8. I suppose it will also work for other digital modes, and should really be able to work with almost any radio provided the PTT voltage & current don't exceed the specifications of the SSR I used.

Those of you who know me know that I'm a real hacker when it comes to hardware, so all suggestions for improvement are always welcome (email: my call at ARRL.net). Or post here so all can kibitz!

--
John - WA2FZW


Re: antenna tuner for uBitx

Keith VE7GDH
 

Rajan VU3JYT wrote...

what type of antenna tuner required for uBITX as
it has only 10w power
Some might prefer a "homebrew" approach, but I have
an Elecraft T1 auto-tuner that I'm very happy with.
They rate it at 20W for SSB and CW but have "stress
tested" it briefly to higher power levels.

http://www.elecraft.com/T1/T1.htm

--
73 Keith VE7GDH

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

Joe Puma
 

Curious why you didn’t opt for a serial PTT circuit for the btx40 which is just as easy to make and easily controlled through a serial port which can be configured in wsjtx. 

I was interested in picking up a easydigi for digital modes with my HF rig because I was getting all types of interference, noise, or even RF into the audio lines with it directly connected, so I need something to isolate but I found a pretty cool cat dongle with audio features for my Yaesu FT-840. 

If you get the right easydigi it will also have the components on it for an isolated push to talk as well. So I was just wondering why you went the Vox route. 

Joe
KD2NFC 





On Mar 20, 2018, at 8:32 AM, John P <j.m.price@...> wrote:

As promised, I uploaded the description of the simple VOX interface between my PC and the BitX-40 that I've been using for FT-8. I suppose it will also work for other digital modes, and should really be able to work with almost any radio provided the PTT voltage & current don't exceed the specifications of the SSR I used.

Those of you who know me know that I'm a real hacker when it comes to hardware, so all suggestions for improvement are always welcome (email: my call at ARRL.net). Or post here so all can kibitz!

--
John - WA2FZW

Re: Mechanical work is done...

Nelson
 

Howdy Steve,

My "forte" is radios that glow in the dark so most all of my test equipment also glows in the dark. As to what all that equipment on my bench does is heat my shop in the winter :-)

(please note my fascination with magic eye tubes...) 

Nelson
KG7GYS


I always thought the Universe was a wonderfully strange place until I studied particle physics.  I now know the universe is, in fact, profoundly odd in nature... 

On Mon, Mar 19, 2018 at 9:38 PM, Steve Thatcher <stevep2p@...> wrote:
Looks good Nelson.  I do like that speaker grill....The pic of your test bench is...um...awesome!  (as Steve asks himself- "what does all that stuff DO??")  Aloha, Steve

Virus-free. www.avg.com




--
I always thought the Universe was a wonderfully strange place until I studied Particle Physics - I now know the Universe is, in fact, profoundly odd in nature

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

Randy
 

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

Gordon Gibby
 

most computers now don't have serial ports, so it is extra $$ to purchase converter.   Cheaper for me just to take audio, add a few transistors/relay.   Lots of different ways to do it.      We used inexpensive audio transformers from China in our design.   


http://www.qsl.net/nf4rc/SmallBookSoundCardConstructionManual2.pdf




From: BITX20@groups.io <BITX20@groups.io> on behalf of Joe Puma <kd2nfc@...>
Sent: Tuesday, March 20, 2018 12:25 PM
To: BITX20@groups.io
Subject: Re: [BITX20] A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8
 
Curious why you didn’t opt for a serial PTT circuit for the btx40 which is just as easy to make and easily controlled through a serial port which can be configured in wsjtx. 

I was interested in picking up a easydigi for digital modes with my HF rig because I was getting all types of interference, noise, or even RF into the audio lines with it directly connected, so I need something to isolate but I found a pretty cool cat dongle with audio features for my Yaesu FT-840. 

If you get the right easydigi it will also have the components on it for an isolated push to talk as well. So I was just wondering why you went the Vox route. 

Joe
KD2NFC 





On Mar 20, 2018, at 8:32 AM, John P <j.m.price@...> wrote:

As promised, I uploaded the description of the simple VOX interface between my PC and the BitX-40 that I've been using for FT-8. I suppose it will also work for other digital modes, and should really be able to work with almost any radio provided the PTT voltage & current don't exceed the specifications of the SSR I used.

Those of you who know me know that I'm a real hacker when it comes to hardware, so all suggestions for improvement are always welcome (email: my call at ARRL.net). Or post here so all can kibitz!

--
John - WA2FZW

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

Randy
 

Re: ESP8266 or ESP32 Raduino Alternatives?

bobolink
 

I've been evaluating the ESP32 (wireless stacks, dual-core concurrency and FreeRTOS) but sorry to say I haven't actually tried compiling the uBitx code.
I know there are some libraries that haven't been converted (like the InfraRed controller IRRemote) but I don't think there is anything exotic in the bitx code that would cause problems.

The setup is here: GitHub if you'd like to try.

If you have a link to a file, I could at least see if it compiles on my espressif esp32 dev board: esp-devc

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

Joe Puma
 

Ha creative. But it’s just usb to serial. I use this circuit pictured for my PTT after the usb to serial dongle. I have another diode on the transceiver side. image1.png 

I use with my  Baofeng HT and Yaesu radio. This is my ghetto digital mode interface I use with the Yaesu.

image2.jpeg

I wanted to get this for the Yaesu for its isolation transformers and compactness. 


Joe
KD2NFC 





On Mar 20, 2018, at 12:42 PM, Randy <randy@...> wrote:

Any gotchas replacing the TDA2822 with an LM386? #ubitx #ubitx-help

Ben Kuhn
 

I finally got my uBitX yesterday and discovered it has the dreaded WX version of the TDA2822.  I've got a couple of LM386 op amps and some sockets floating around the parts bin, so I figure the safest thing to do is to build an adapter for the LM386 as described on ubitx.net.  I'm planning on doing the 0.1uf cap between pins 1 and 8 to get the gain similar to the TDA2822.  Are there any other gotchas I need to think about before doing this?

Re: For sale micro bitx

Fred Buecker
 

If Walter falls through, I'll take it. I am ordering my own on Thursday otherwise.

-Fred
KC3HMS

On Tue, Mar 20, 2018, 10:06 AM Walter <W9KJO@...> wrote:
On Mon, Mar 19, 2018 at 08:12 pm, <W7zim@...> wrote:
Just received number 546/3 with the dreaded WX op amp.

It's for sale for $109 postage paid any where in USA. Brand new and untouched.

Prefer paypal.

If interested please contact me off line.

w7zim at Yahoo dot com

Fred, W7ZIM
Ill buy it from you using Paypal.

Please send needed info to W9KJO@...
--
73, W9KJO
Walter

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

Randy
 

Easy Gigi in case with external USB soundcard

Re: A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

John P
 

On Tue, Mar 20, 2018 at 09:25 am, Joe Puma wrote:
If you get the right easydigi it will also have the components on it for an isolated push to talk as well. So I was just wondering why you went the Vox route. 
Seemed like a good idea at the time, and I had all the parts on hand!
 
--
John - WA2FZW

Microphone, simple fix.

Dennis Voorhees
 

I have a UBitX from the second batch. I tried several published mods to get a decent output on the stock mic element, but nothing was satisfactory. It also involved a lot of fine work on a surface mount board. My eyes are not as good or hands as steady as I would like. So I rummaged around in the vast AD3O junk box and found a broken headset ( I don't throw much of anything out, with a cord attached), with a condenser mic element pellet. This one was a 3 wire with a separate shield ground connection, not sure that had anything to do with it. I wired it into my Pill Bottle mic enclosure and my Power out went from about a watt on peaks, to about 5 watts, With both of them I could whistle up over 10 watts. So pretty painless, it just took some experimentation, and a junk box. The bottom line is, I think the mic element that comes with the UbitX is not that well matched to the circuit. There used to be condenser elements available from Radio Shack, but that ship has sailed. I also see they are available from many sources. Maybe worth ordering a few, out in the wild for experimentation. 

Denny AD3O

Re: Microphone, simple fix.

 

Denny,

I found the same thing. I didn't use any of the mic elements that came with all of my Bitx's, (none of them sounded that good),  I found a couple of elements that did sound good and use the same mics for all of my projects.

Joel
N6ALT

Re: 13.8 v power supplies safe for bitx?

Tim Gorman
 

Walter,

I have a 1 amp fast-blow fuse on the red lead going to the main circuit
board and a 2 amp fast-blow fuse on the brown lead going to the power
amp circuit.

My ammeter shows 2 amp peaks on the very loudest audio into the mic.
This load apparently doesn't last long enough to blow the 2amp fuse.
Usual peaks are around 1 amp

I've never seen the current go above about 250ma on receive even with
the volume control way up on a strong signal. My TDA2822W chip never
gets warm under normal use. I have used an 8ohm speaker and a 16ohm
speaker to test the current draw. I use a mono jack on the speaker lead
and a permanently wired internal speaker that the mono jack disconnects
when an external speaker is plugged in.

I suspect I can get by with a 500ma fast-blow fuse on the main board. I
might try that the next chance I get.

tim ab0wr

On Tue, 20 Mar 2018 07:16:13 -0700
"Walter" <@whuyckjr> wrote:

On Thu, Mar 15, 2018 at 06:12 pm, Tim Gorman wrote:


Jerry,

I'm not sure everyone understands what foldback current limiting
is. Your message 40729 explains it well. In action it is like a
fuse. The power supply opens the power lead until the operator
takes an action.

It is not the same thing as current limiting.

I don't have any power supplies with foldback current limiting so
for me a fuse is the next best thing.

tim ab0wr

On Thu, 15 Mar 2018 16:46:37 -0700
"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:


True.  The standard current limiting supply I described is not
something to lean on to avoid driving the final too hard, that's
not what I was suggesting. If there's a current limit on the
finals, should be foldback current limiting:
https://groups.io/g/BITX20/message/40719
OK Great info so what size fuse?  What is the maximum safe current
for the circuit?

Thanks
 
--
73, W9KJO
Walter

Re: 13.8 v power supplies safe for bitx?

Tim Gorman
 

Walter,

I have a 1 amp fast-blow fuse on the red lead going to the main circuit
board and a 2 amp fast-blow fuse on the brown lead going to the power
amp circuit.

My ammeter shows 2 amp peaks on the very loudest audio into the mic.
This load apparently doesn't last long enough to blow the 2amp fuse.
Usual peaks are around 1 amp

I've never seen the current go above about 250ma on receive even with
the volume control way up on a strong signal. My TDA2822W chip never
gets warm under normal use. I have used an 8ohm speaker and a 16ohm
speaker to test the current draw. I use a mono jack on the speaker lead
and a permanently wired internal speaker that the mono jack disconnects
when an external speaker is plugged in.

I suspect I can get by with a 500ma fast-blow fuse on the main board. I
might try that the next chance I get.

tim ab0wr

On Tue, 20 Mar 2018 07:16:13 -0700
"Walter" <@whuyckjr> wrote:

On Thu, Mar 15, 2018 at 06:12 pm, Tim Gorman wrote:


Jerry,

I'm not sure everyone understands what foldback current limiting
is. Your message 40729 explains it well. In action it is like a
fuse. The power supply opens the power lead until the operator
takes an action.

It is not the same thing as current limiting.

I don't have any power supplies with foldback current limiting so
for me a fuse is the next best thing.

tim ab0wr

On Thu, 15 Mar 2018 16:46:37 -0700
"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:


True.  The standard current limiting supply I described is not
something to lean on to avoid driving the final too hard, that's
not what I was suggesting. If there's a current limit on the
finals, should be foldback current limiting:
https://groups.io/g/BITX20/message/40719
OK Great info so what size fuse?  What is the maximum safe current
for the circuit?

Thanks
 
--
73, W9KJO
Walter