Date   
Re: ubitx - stop press

REJIMON G <rejimontkm@...>
 

I think C1969  in pushull mode will give constant power in all bands

Sent from my iPhone

On 11-Dec-2017, at 12:16 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

Hfsignals.com write-up also mentions that power out is 10 Watts up to 10mhz, falls off to 2 Watts at 30mhz.
It is tough to drive IRF510's at 30mhz, but the WA2EBY amplifier uses two IRF510's in push-pull
like this to give 40 Watts up through 30mhz from a 28v supply.  Perhaps we can borrow some of the
WA2EBY design to approach that kind of performance.  May require beefier caps and coils.
And maybe an additional driver stage. 
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart1.pdf
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart2.pdf

Also in the hfsignals uBitx write-up:  "TIA".
Not found in most dictionaries.
Means "Termination Insensitive Amplifier"
    http://w7zoi.net/bidirectional_matched_amplifier.pdf

Jerry, KE7ER


On Sun, Dec 10, 2017 at 10:18 pm, AndyH wrote:
Just the close the circle, so to speak.  Farhan has additional comments in the sales write-up for the µBITX:
The power chain uses four common plastic 2N3904s in push-pull as drivers. The 2N3904s have enough gain at 30 MHz. The 2N2219s tried  earlier were found to have low gain at higher frequencies.

Re: ubitx - stop press

Jerry Gaffke
 

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 - stop press

Ashhar Farhan
 

Try the RD15HVF1. That is the simplest. The only the pin out is different, you will have to twist the the legs and figure how to insert them into the same pinout as the IRF510.

- f

On Mon, Dec 11, 2017 at 12:23 PM, REJIMON G <rejimontkm@...> wrote:
I think C1969  in pushull mode will give constant power in all bands

Sent from my iPhone

On 11-Dec-2017, at 12:16 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

Hfsignals.com write-up also mentions that power out is 10 Watts up to 10mhz, falls off to 2 Watts at 30mhz.
It is tough to drive IRF510's at 30mhz, but the WA2EBY amplifier uses two IRF510's in push-pull
like this to give 40 Watts up through 30mhz from a 28v supply.  Perhaps we can borrow some of the
WA2EBY design to approach that kind of performance.  May require beefier caps and coils.
And maybe an additional driver stage. 
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart1.pdf
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart2.pdf

Also in the hfsignals uBitx write-up:  "TIA".
Not found in most dictionaries.
Means "Termination Insensitive Amplifier"
    http://w7zoi.net/bidirectional_matched_amplifier.pdf

Jerry, KE7ER


On Sun, Dec 10, 2017 at 10:18 pm, AndyH wrote:
Just the close the circle, so to speak.  Farhan has additional comments in the sales write-up for the µBITX:
The power chain uses four common plastic 2N3904s in push-pull as drivers. The 2N3904s have enough gain at 30 MHz. The 2N2219s tried  earlier were found to have low gain at higher frequencies.


Re: ubitx - stop press

Ashhar Farhan
 

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 Case

ekelley
 

Project case:
Click here

Re: uBITX Case

ekelley
 

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".



Re: dead sites on BitX40 Site

Ashhar Farhan
 

hfsigs.com is pointing to hfsignals.com anyway

- f

On Mon, Dec 11, 2017 at 12:21 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
The Bitx40 stuff all got moved over to the new hfsignals.com domain.
Go there, click "Bitx40".

Jerry, KE7ER


On Sun, Dec 10, 2017 at 10:47 pm, Joe Munson wrote:
I tried to access teh buy site and the wire it up site on the BitX 40 website.  Except for thg ;home page, all the other sites give me a error requested site not found.   What is going on with BitX40 site?.  Have they shut down?


Re: ubitx - stop press

Jerry Gaffke
 

OK, that's good to know.
Sounds like the uBitx can do better than 2W on 30mhz if you crank up the gain,
but best remember to crank it back down or you will distort when back on 7mhz.
And if that's too inconvenient, splurge on a couple RD15HVF1's  (keeping it down at 12v).
Jerry, KE7ER


On Sun, Dec 10, 2017 at 11:05 pm, Ashhar Farhan 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. 

Re: Reverse polarity diode circuit

César EA3IAV
 

What about Tvs diodes? Wouldn’t it be easier? Adding a fuse ot the wire of course

Re: ubitx - stop press

Trent Trent <vk7hrs@...>
 

With the rh15hvf or whatever they are does anything need to be changed like transformers and csn the PS power on it run 20V like the BitX40

On 11 Dec. 2017 6:05 pm, "Ashhar Farhan" <farhanbox@...> wrote:
Try the RD15HVF1. That is the simplest. The only the pin out is different, you will have to twist the the legs and figure how to insert them into the same pinout as the IRF510.

- f

On Mon, Dec 11, 2017 at 12:23 PM, REJIMON G <rejimontkm@...> wrote:
I think C1969  in pushull mode will give constant power in all bands

Sent from my iPhone

On 11-Dec-2017, at 12:16 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

Hfsignals.com write-up also mentions that power out is 10 Watts up to 10mhz, falls off to 2 Watts at 30mhz.
It is tough to drive IRF510's at 30mhz, but the WA2EBY amplifier uses two IRF510's in push-pull
like this to give 40 Watts up through 30mhz from a 28v supply.  Perhaps we can borrow some of the
WA2EBY design to approach that kind of performance.  May require beefier caps and coils.
And maybe an additional driver stage. 
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart1.pdf
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart2.pdf

Also in the hfsignals uBitx write-up:  "TIA".
Not found in most dictionaries.
Means "Termination Insensitive Amplifier"
    http://w7zoi.net/bidirectional_matched_amplifier.pdf

Jerry, KE7ER


On Sun, Dec 10, 2017 at 10:18 pm, AndyH wrote:
Just the close the circle, so to speak.  Farhan has additional comments in the sales write-up for the µBITX:
The power chain uses four common plastic 2N3904s in push-pull as drivers. The 2N3904s have enough gain at 30 MHz. The 2N2219s tried  earlier were found to have low gain at higher frequencies.


Re: Reverse polarity diode circuit

Trent Trent <vk7hrs@...>
 

Put a alarm in the case with a diode so if the polarity is wrong it will annoy the crap out of you and everyone else near you 

On 11 Dec. 2017 2:26 pm, "Vince Vielhaber" <vev@...> wrote:

The better news, you can get them all day long from Tayda for 16 cents each. But they only have 119,418 of them in stock.   To the US, shipping from Tayda is only a week for their slow boat shipping. Tayda's minimum order is $5, so for another $3 and change you can get that replacement nano!

Vince.



On 12/10/2017 02:48 PM, Jack Purdum via Groups.Io wrote:
All:

The good news: I just ordered a mega-munch of 3A, 30V polyfuses that I'd
be happy to share for $1, including domestic shipping.
The bad news: They're coming from China, so will likely be several
weeks. I'll make a post here after they've arrived.

Jack, W8TEE


------------------------------------------------------------------------
*From:* Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io>
*To:* BITX20@groups.io
*Sent:* Sunday, December 10, 2017 2:24 PM
*Subject:* Re: [BITX20] Reverse polarity diode circuit

Yup, a Polyfuse works great.
Can add a resistor and red LED across it as an idiot light so you know
when to  execute the dope-slap.
(Can also do that for a fuse)

Though Farhan is looking for stuff that's easy to scrounge, doubt a
Polyfuse will make it into the next rev.
A small diode for both reverse protection and overcurrent protection on
the main rig might be the best bet.

Jerry, KE7ER


On Sun, Dec 10, 2017 at 11:16 am, Don Cantrell wrote:

    My favorite is the Polyfuse.





--
  Michigan VHF Corp.   http://www.nobucks.net/   http://www.CDupe.com/
                          http://www.metalworkingfun.com



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?