Date   
Re: ubitx - stop press

REJIMON G <rejimontkm@...>
 

hi, what's the maximum practical voltage,Vdd that can apply to IRF510.. I tested up to 37V for continuous one 
minute ....
Sent from my iPhone

On 11-Dec-2017, at 12:35 PM, Ashhar Farhan <farhanbox@...> wrote:

Jerry, you can crank up the 'volume' through the 100 ohms predriver preset.

- f

On Mon, Dec 11, 2017 at 12:27 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
I'm wondering if we can bring 30mhz output power up to the same level as 7mhz
by borrowing the WA2EBY matching network at the front of the IRF510's.
Two watts of SSB is pretty hardcore.

On Sun, Dec 10, 2017 at 10:53 pm, Ashhar Farhan wrote:
One could push it that high, but not on the same PCB as the rest of the circuitry. I would say that 30 watts should be the tops. the RF ground loops on the board can make the entire TX chain wobbly. that said, i haven't tried anything of the sort. I'm curious to know what happens, i havent transmitted more than 25 watts for two decades.
 


Re: ubitx is available for $109, there are a3 catches

Alex - PA1FOX
 

Hi Jerry,
The diode will short out if reverse polarity is done. Normally PSU have fuses and that will blow. 
But yes an in line fuse would be advisable.
I prefer to use a a relay with a diode that will engage if the supply is reversed. the contacts can also be use to trigger an alarm or buzzer.
73's
Mans. 9H1GB


Yes, I use this relay method with my uBitx as well. The same relay is used to switch the rig to the built in batteries when unplugged from the external power supply. And in case of reverse polarity applied, the rig keeps on working on the built in batteries. I also plan to add an under/overvoltage protection: the relay will not switch when less then 11 volts or more than 15 volts are applied. This will keep the rig in a controlled supply voltage range whatever power supply is used. (ok.. don't use an AC power supply directly....)

73, Alex
PA1FOX

Re: ubitx - stop press

Jeff Omundson
 

Hi Ashhar,
I just noticed this issue now but ordered a ubitx on Friday.  I just wanted to confirm that the four filter option will be implemented on the radios that get shipped out.  Or will there be a different solution?

Thank you for coming up with these designs and taking the time and effort required to share them all over the world!

-Jeff
KF7RPI

Re: ubitx - stop press

Ryan Flowers
 

He's indicated in other threads that the four filter version is final. It's also clear in the pictures of the production uBITX and the schematic. There's nothing to worry over :)

--
Ryan Flowers - W7RLF
MiscDotGeek.com
Multi Band BITX40
The BITX40 FAQ

Re: ubitx is available for $109, there are a3 catches

nirajmp12@...
 

Is it with reduino?

ubitx keyer

Ashhar Farhan
 

i havent yet documented the keyer, keith asked about it, so here it is. 

USING THE CW KEYER
here is a short answer : connect the paddle with a 2.2K resistor from the dot padddle to the CW key, a 10K resistor from the dash paddle to the CW key


HOW IT WORKS

first an explanation for the trickery that is to follow. i ran out of pins for ubitx. so, i had to use  A6 for the keyer. A6 doesn't have a built-in pull-up resistor like other pins. So, we place a 4.7K resistor between A6 and the +5v line. Now, follow me closely ...

First, we connect a straight key to the A6 and ground. When you push it down, A6 goes to ground. When you release it, A6 goes up to 5v. simple enough.

Now, lets connect a CW paddle. The CW paddle has a ground and two posts (one for the dots and the other for the dashes). We put a 2.2k resistor from the dot paddle to the A6 and a 10K resistor from the dash post to the A6. 

When we press on the dot paddle, 2.2K shorts to the ground. The 2.2K and the 4.7K resistor together form a voltage divider. The voltage at A6 is now somewhere between 0 and 5v. Infact, it is about 5V x  2.2K/(4.7K+2.2K) ~ 1.6v.

When we press the dash paddle, the 10K shorts to the ground. 10K and the 4.7K resistor divide the 5V to 3.4V.

So, in summary, 
0v is the straight key down
1.6v is dot paddle down
3.4v is dash paddle down

the rest is the software in. read the source, luke.

- f

Re: ubitx keyer

Ryan Flowers
 

Dang it, now I'm going to have to learn CW just so I can take advantage of this :p

--
Ryan Flowers - W7RLF
MiscDotGeek.com
Multi Band BITX40
The BITX40 FAQ

Re: ubitx keyer

 

You have one more possibility I.e when both paddles are pressed! 

Do the iambic did-dah-did-dah

Raj

Sent from my iPhone

On 11-Dec-2017, at 14:26, Ashhar Farhan <farhanbox@...> wrote:

i havent yet documented the keyer, keith asked about it, so here it is. 

USING THE CW KEYER
here is a short answer : connect the paddle with a 2.2K resistor from the dot padddle to the CW key, a 10K resistor from the dash paddle to the CW key


HOW IT WORKS

first an explanation for the trickery that is to follow. i ran out of pins for ubitx. so, i had to use  A6 for the keyer. A6 doesn't have a built-in pull-up resistor like other pins. So, we place a 4.7K resistor between A6 and the +5v line. Now, follow me closely ...

First, we connect a straight key to the A6 and ground. When you push it down, A6 goes to ground. When you release it, A6 goes up to 5v. simple enough.

Now, lets connect a CW paddle. The CW paddle has a ground and two posts (one for the dots and the other for the dashes). We put a 2.2k resistor from the dot paddle to the A6 and a 10K resistor from the dash post to the A6. 

When we press on the dot paddle, 2.2K shorts to the ground. The 2.2K and the 4.7K resistor together form a voltage divider. The voltage at A6 is now somewhere between 0 and 5v. Infact, it is about 5V x  2.2K/(4.7K+2.2K) ~ 1.6v.

When we press the dash paddle, the 10K shorts to the ground. 10K and the 4.7K resistor divide the 5V to 3.4V.

So, in summary, 
0v is the straight key down
1.6v is dot paddle down
3.4v is dash paddle down

the rest is the software in. read the source, luke.

- f

Re: ubitx AGC?

Weddig, Henning-Christof <Henning-Christof.Weddig@...>
 

Jerry,
I am in the process to do the following on my "original" BITX40 (yes I got one from Farhan):
use an opamp with a gain of 10 (20 dB) and an audio AGC system using a SSM2166.
Fortunately I purchased a pcb from ZL1CVD with the DIL chip via ebay years ago... Unfortunatley he does not sell this pcb any more...

The SSM2166 has a dynamic range of 60 dB, the opamp in front of it instead of the first discrete amp aftger dthe demod will amplifiy the audio into a range the SSM2166 can handle.
Also the SSM2166 has a provision of outputtting a AGC voltage -- may be used for driving an S-meter.

Let´s see what comes out.

Henning Weddig
DK5LV


Am 10.12.2017 um 21:33 schrieb Jerry Gaffke via Groups.Io:

No AGC on the production uBitx.
The original schematic for the uBitx here: http://www.phonestack.com/farhan/ubitx/ubitx.html
shows the second half of the TDA2822 used as an AGC amp, attenuating the audio through the 2n7002 nfet.
Apparently Farhan found that he preferred using the rig without that particular AGC scheme.
As Henning/DK5LV has shown in the distant past, that npn audio pre-amp stage for rx is a dynamic range bottleneck.
if AGC is applied after it around the volume control as the above AGC scheme does.
I think something like the original uBitx AGC level detect could work, but we'd be better off if the attenuation occurred
somewhere prior to the npn audio pre-amp: https://groups.io/g/BITX20/topic/5913954
Jerry, KE7ER
On Sun, Dec 10, 2017 at 12:01 pm, <jettoblack@...> wrote:
Does the uBitx have AGC? It was discussed in some of the previous
threads, but the website only has this comment: "The audio amplifier
uses one section of the TDA2822 – a quieter device compared to the
LM386. It has two audio channels, the second channel is kept free
for use as an AGC audio amplifier."  I am not sure if that means an
AGC can be added later, or is it already present?

Re: W8TEE B40 real time clock connections #w8tee

Rob Cox (N4MN)
 

Thanks Jack.


On Sun, Dec 10, 2017 at 07:46 pm, Jack Purdum wrote:
The RTC was just an experiment

Re: ubitx AGC?

Alex - PA1FOX
 

I am using the AGC from the original uBitx design, but found out the time constant of 1uF and 100k to be far too low which makes it a very fast AGC, not giving a nice sound to voices. I changed to 1,5 uF and 4M7 and now the voices of stronger stations are nice and clear (they 'push' the noise level down ) and the gain comes up nice and easy when the QRG is clear. I think I'll keep it this way.

73, Alex
PA1FOX

Re: HELP BITX40 RADUINO

yo3ifx@...
 

Hello all!
I installed raduino version 1.27.2 and I would like to use a dds oscillator for the carrier oscillator (BFO) and I would like to know if this can be done and what raduino pine is taking the signal for BFO.
Thank you!!

Re: ubitx - stop press

Michael Monteith
 

The datasheet shows a max of 100V.   But I haven't looked at the schematic to see if there are other components involved.   So that's just for the device itself.  Of course keep it well below that. 

73, Michael
KM4OLT

Re: ubitx - stop press

Michael Monteith
 

Jerry,
 The IRF510 is really a general purpose device.  I think initially it was chosen in a lot of projects when it came out due to it's low on-resistance.  However it's not really a "rf device". 
This guy made a decent 50watt amp for the IRF510. 
A Simple Cheap 50 Watt PA

  However this one uses true RF devices.  Which I think is a much better approach.  I haven't looked at the devices themselves closely to see if they could be substituted with the IRF510 or not directly.   I was simply looking for a rf device that could be used for a new design. I just happened to see this discussion and share what information I have so far. 
G6LBQ - HF LINEAR AMPLIFIER

 So maybe someone can expand the research.

73, Michael
KM4OLT

Re: ubitx keyer

Keith VE7GDH
 

Asharr VU2ESE wrote…

I haven't yet documented the keyer, Keith asked about it, so here it is.…
Thanks for the explanation. It sounds like a good solution.

Perhaps when you get a moment you could let us know the approximate RX & TX current for the uBITX.

--
73 Keith VE7GDH

Re: HELP BITX40 RADUINO

Allard PE1NWL
 

I'm currently working on raduino v2.0 which provides this.
To be released soon.

73 Allard PE1NWL

On Mon, December 11, 2017 14:06, yo3ifx via Groups.Io wrote:
Hello all!
I installed raduino version 1.27.2 and I would like to use a dds
oscillator for the carrier oscillator (BFO) and I would like to know if
this can be done and what raduino pine is taking the signal for BFO.
Thank you!!

Re: uBITX Case

Dennis Zabawa
 

This is turning into a fountain of mis-information.  Could someone provide a verified drawing showing the envelope dimensions of a finished  uBITX board assembly?

Re: uBITX Case

Gordon Gibby <ggibby@...>
 

Dennis Zabawa wrote:

"This is turning into a fountain of mis-information.  Could someone provide a verified drawing showing the envelope dimensions of a finished  uBITX board assembly?"



I think this is the information you need:

"Don't have an EF01 or a uBitx, but Farhan's post #35063 says the board is:
    6" by 5.5", 
    1. the heatsink protrudes out of the backside side (6" long side)
    2. the raduino plugs into the front and protrudes by 0.5", so you will need 6" depth for the box.
    you could, if you wanted to, remove the display from being plugged in, run a 7 wire cable 
    from the raduino to the LCD board and place the LCD board anywhere else. but, roughtly, 
    6" x 6" is what it needs (for a very very tight fit, i couldn't get the volume control to the left of the raduino in that small a space).

And post #35065 says
    At least 2-1/2" inches if you are on standoffs. The stand-offs are 1/2 inch, the display is another 1-3/4 inch above the pcb"



You could draw that with a pencil to get an idea of what it looks like.  


Cheers!!




From: BITX20@groups.io <BITX20@groups.io> on behalf of Dennis Zabawa <kg4rul@...>
Sent: Monday, December 11, 2017 9:10 AM
To: BITX20@groups.io
Subject: Re: [BITX20] uBITX Case
 
This is turning into a fountain of mis-information.  Could someone provide a verified drawing showing the envelope dimensions of a finished  uBITX board assembly?

Re: uBITX Case

Jack, W8TEE
 

Banggood sells a similar case to $10:

I bought two of these and they're pretty nice.

Jack, W8TEE


From: ekelley <ekelley828@...>
To: BITX20@groups.io
Sent: Monday, December 11, 2017 2:13 AM
Subject: Re: [BITX20] uBITX Case

Same box on Bangood for 9.99

On 12/11/2017 12:26 AM, Thomas Sharka via Groups.Io wrote:


 


Sent from Yahoo Mail. Get the app


On Monday, December 11, 2017 1:19 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:


Don't have an EF01 or a uBitx, but Farhan's post #35063 says the board is:
    6" by 5.5", 
    1. the heatsink protrudes out of the backside side (6" long side)
    2. the raduino plugs into the front and protrudes by 0.5", so you will need 6" depth for the box.
    you could, if you wanted to, remove the display from being plugged in, run a 7 wire cable
    from the raduino to the LCD board and place the LCD board anywhere else. but, roughtly,
    6" x 6" is what it needs (for a very very tight fit, i couldn't get the volume control to the left of the raduino in that small a space).

And post #35065 says
    At least 2-1/2" inches if you are on standoffs. The stand-offs are 1/2 inch, the display is another 1-3/4 inch above the pcb

The EF01 is 200mm wide x 175mm deep by 70mm high, so  7.87" wide x 6.89" x 2.75"
I assume those are outside dimensions, inside would be about 1/4" less?
So height is getting close if you use the 1/2" standoffs supplied with the uBitx, but those could be removed.
Plenty wide to get all the controls in.
Heatsink should probably protrude out the back anyway so it gets some airflow and can be checked
occasionally to see if it's getting hot.  Guess I'd figure out how to mount a heatsink with screws coming up
from the bottom of the box, have the heatsink extend into the box by 0.75" or so to where the IRF510's could
be bolted to it after mounting the uBitx main board in place.  Use a big heatsink swiped from an old computer.

Me, I'd prefer a metal box.  This is about the same price as that EF01:
  https://www.jameco.com/z/CMC11949-R-Case-Metal-7-3-L-x-6-3-W-x-2-75-H-50-Cs_208929.html
The 6.3" wide would be constraining, as Farhan suggests above we might want it wider to 
have a nice spot for a left hand volume control.  But I could live with volume near the tuning knob.
And the aluminum bottom and back panel of that chassis should make a fine heatsink
for the IRF510's using TO220 insulating kits.  Box is 7.3" deep, so might need a 0.5" thick plate of
aluminum between the IRF510's and the back of the box.  Or could remount the IRF510's
to the bottom of the uBitx board and bolt them to the bottom of the box.

Jerry, KE7ER

On Sun, Dec 10, 2017 at 08:49 pm, <paulsmi55@...> wrote:
I'm looking at the footprint of my freshly-ordered uBITX and wonder if it would fit into the venerable Excellway EF01 case that folk have used to house their BITX40s ?
Can't track down internal dimensions for the box but it looks like it will be a tight fit if it does. May have to make a plan with the heatsinking arrangement to win back that 1/4".






Virus-free. www.avast.com

UBITX Questions

Jason N3YUG
 

First, does anyone have video of the latest UBITX in action.  Does the new UBITX have S-meter stock on the new kits going out?

Thanks for info.

Jason
N3YUG