Date   
Re: ND6T AGC implementation for uBIT-X

John
 

Yup post them.. :)

Re: ND6T AGC implementation for uBIT-X

William R Maxwell
 

Yes Ion, please post the files.

Bill, VK7MX


On 27/04/2018 9:16 AM, Ion Petroianu, VA3NOI wrote:
Hi Guys!
I have both versions of the board designed.
Through hole with a size of 17X38 mm, single side.
SMT with a size of 18X31 mm. SMT components are 0805. 1 uF cap is tantalum or niobium polarized.
In terms of performance I am expecting better results with the SMT board.
I have ordered through hole version for experimenting with some values (AGC release time minimum resistor and coupling capacitors on RF line) at PCBway and they are in route to Canada.
The PCBs have provision for adding a pot to adjust AGC release time and a switch to disable the AGC.
If interested let me know and I will post the files (schematic, board layout and Gerbers).
Feel free to use the files as you can see fit. If anyone wants to put kits together just do it.

73
Ion

VA3NOI


Re: ND6T AGC implementation for uBIT-X

Ion Petroianu, VA3NOI
 

Hi Guys!
I have both versions of the board designed.
Through hole with a size of 17X38 mm, single side.
SMT with a size of 18X31 mm. SMT components are 0805. 1 uF cap is tantalum or niobium polarized.
In terms of performance I am expecting better results with the SMT board.
I have ordered through hole version for experimenting with some values (AGC release time minimum resistor and coupling capacitors on RF line) at PCBway and they are in route to Canada.
The PCBs have provision for adding a pot to adjust AGC release time and a switch to disable the AGC.
If interested let me know and I will post the files (schematic, board layout and Gerbers).
Feel free to use the files as you can see fit. If anyone wants to put kits together just do it.

73
Ion

VA3NOI

Re: ND6T AGC implementation for uBIT-X

alans77@...
 

Sign me up for 2 kits.
73,
Alan N4AYE

Re: ND6T AGC implementation for uBIT-X

Dana Marcy
 

Hello All
    I would be interested in getting 4 kits. 2 for myself and 2 for others in Calgary, Canada (since I know they are around) 
Thank You in Advance
73 

Re: ND6T AGC implementation for uBIT-X

Jonathan
 

I would order 2 kits, with parts.   Prefer larger 1206 parts but 0805s are okay.

-Jonathan

Re: minimum supply voltage

vajra guru
 

Thanks folks, great info... 73 de VE3EIT


On Thursday, April 26, 2018, Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
Good to know.

The discussion thus far is mostly about the LM7805 linear regulator on the Raduino.
The TDA2822 and LM7805 set definite max and min voltages, but nobody
really knows over what range of supply voltages the remainder of the
analog circuits in the rig will operate properly.

On Thu, Apr 26, 2018 at 01:18 pm, Tim Gorman wrote:
My ubitx main board pulls about .6amp in transmit when the PA is fed
from a separate power supply.

tim ab0wr

Re: ubitx-VE1BWV/VU2SPF TIPS

Joe
 

Where is your project located?


On Thu, Apr 26, 2018, 5:23 PM Bo Barry <wn4ghv@...> wrote:
View on line not via the emails. Bottom right click on More.  Lots of stuff there.

Re: No Speaker Audio #ubitx

iz oos
 

Indeed, replacing the TDA2822 has solved the audio in my case. 73 franco


Il 26/apr/2018 10:51, "iz oos" <and2oosiz2@...> ha scritto:

QSL. Tnx. Franco


Il 26/apr/2018 10:15, "Raj vu2zap" <rajendrakumargg@...> ha scritto:
The U1 only. There are equivalents for 2822 also.

Don't used chips with marking WX on, they are failing!

Raj

At 26-04-18, you wrote:

Should I replace U1 the TDA2822 or Q70 the 2N3904?

Il 26/apr/2018 09:04, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
Blown audio amp chip. Desolder and put a socket.

Raj

At 26-04-18, you wrote:

I have a similar problem. My speaker connector is standard RCA. While testing for about half an hour it suddenly muted, nothing from the speaker.

Il 26/apr/2018 08:43, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
Since you have connected L and R to the audio out then you CANNOT use a mono jack.
A mono jack shorts out R and therefore L also.
Remove the inner R wire (the short jumper in photo) and you should get your audio back
unless the chip has died.
Raj
At 26-04-18, you wrote:

So, my build is not standard. It powers on, but I get no sound even when I turn up the volume all the way.
I confirmed the speaker is 8 ohm and it is mono (see connector in photo)

Re: mono band 2 meters rig based on the micro BITx circuit #ubitx #2meters

freefuel@...
 

Hi Ken, the driving motivation here is for Single Side Band operations, with that said your totally and completely correct there is absolutely no financial benefit to building an FM only VHF circuit. 

with the 45MHz crystal filter I can see it maybe working on 4 Meters, 2 Meters, and maybe 1.25 Meters. so I could see a reasonable compromise being a dual band rig with 2 meters and the option of 4 meters or 222MHz.  for 6 meters I understand a different crystal filter would need to be employed. 

-Justin N2OTH 

Re: mono band 2 meters rig based on the micro BITx circuit #ubitx #2meters

Steve Black
 

You are not alone. I would be glad to see a 6 meter or 2 meter or even dual band radio for AM or SSB or both. It would be easy to conceal from the HOA people. A  small self contained unit would be awesome. Steve kb1chu


On 04/26/2018 05:00 PM, Ken Hansen wrote:
I understand the motivation, but the Chinese are mass-producing dual band HTs for less than $30 delivered to your door, and the Japanese are producing higher-quality units starting at about $120, how much of a premium over these off-the-shelf solutions are you willing to pay to build your own VHF radio? Are you hoping for SSB operation or FM?

Personally, I'd love to see an extremely simple version of the old Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters for under $40 all-in, as a fun club build, but I suspect I'm alone on that desire...

I think it would be fun to have a local net based on low-cost radios and antennas so small no HOA could object to.

Ken, N2VIP

On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:

my attention has turned to building a single band rig for 2 meters and I am curious who might also be interested in such a device.  my initial plan is to build the main circuit board the identical size of the uBITX and later reduce it to within the confines of the common 20 by 4 line LCD character display.  in an attempt to build this as a Handi Talkie rig. 

-Justin N2TOH 

Re: mono band 2 meters rig based on the micro BITx circuit #ubitx #2meters

Ken Hansen
 

I understand the motivation, but the Chinese are mass-producing dual band HTs for less than $30 delivered to your door, and the Japanese are producing higher-quality units starting at about $120, how much of a premium over these off-the-shelf solutions are you willing to pay to build your own VHF radio? Are you hoping for SSB operation or FM?

Personally, I'd love to see an extremely simple version of the old Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters for under $40 all-in, as a fun club build, but I suspect I'm alone on that desire...

I think it would be fun to have a local net based on low-cost radios and antennas so small no HOA could object to.

Ken, N2VIP

On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:

my attention has turned to building a single band rig for 2 meters and I am curious who might also be interested in such a device.  my initial plan is to build the main circuit board the identical size of the uBITX and later reduce it to within the confines of the common 20 by 4 line LCD character display.  in an attempt to build this as a Handi Talkie rig. 

-Justin N2TOH 

Re: ND6T AGC implementation for uBIT-X

Ronald Payne <wb5klj@...>
 

I would be interested in either a board for either Size components , or a "kit" . 

Ron P

mono band 2 meters rig based on the micro BITx circuit #ubitx #2meters

freefuel@...
 

my attention has turned to building a single band rig for 2 meters and I am curious who might also be interested in such a device.  my initial plan is to build the main circuit board the identical size of the uBITX and later reduce it to within the confines of the common 20 by 4 line LCD character display.  in an attempt to build this as a Handi Talkie rig. 

-Justin N2TOH 

Re: minimum supply voltage

Jerry Gaffke
 

Good to know.

The discussion thus far is mostly about the LM7805 linear regulator on the Raduino.
The TDA2822 and LM7805 set definite max and min voltages, but nobody
really knows over what range of supply voltages the remainder of the
analog circuits in the rig will operate properly.


On Thu, Apr 26, 2018 at 01:18 pm, Tim Gorman wrote:
My ubitx main board pulls about .6amp in transmit when the PA is fed
from a separate power supply.

tim ab0wr

Re: ubitx-VE1BWV/VU2SPF TIPS

Bo Barry <wn4ghv@...>
 

View on line not via the emails. Bottom right click on More.  Lots of stuff there.

Re: minimum supply voltage

Tim Gorman
 

My ubitx main board pulls about .6amp in transmit when the PA is fed
from a separate power supply.

tim ab0wr

On Thu, 26 Apr 2018 11:00:23 -0700
"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:

The board is designed to operate at 12v.
I doubt it will work very well at 6v.

That said, in answer to your question, an LM2940-5 has a lower
dropout voltage than the LM7805:
http://www.ti.com/lit/ds/symlink/lm2940c.pdf
http://www.ti.com/lit/ds/symlink/lm340.pdf

The "Dropout Voltage" at the bottom of page 5 of the LM2940c
datasheet says worst case at 1 Amp is 1 Volt. But the Raduino pulls
far less than 1 Amp, likely well under a half volt.  So would work
with 5.5v going in.

Near the bottom of page 6 of the second datasheet above (covers both
LM340 and LM7805) it says the "Dropout Voltage" is "typically" 2
volts at 1 Amp, they don't give a worst case. Will probably be less
than 2v since the Raduino is not pulling much current, but you'd be
on very shaky ground if trying to feed it only 6v.

Jerry, KE7ER

On Thu, Apr 26, 2018 at 09:35 am, vajra guru wrote:


Have received my uBITx but haven't started assembling yet... I was
thinking along similar lines, using 6V to power the board, and
using 24V for the PA... Does it make sense to change out the 7805
voltage regulator for something different to make this work? Thx,
Calvin VE3EIT

Re: ND6T AGC implementation for uBIT-X

Tim Gorman
 

I made a board using a hobby knive. It is far larger than it needs to
be. But it works *well*!.

So put me down for 2 boards. Either 0805 or 1206 will work for me.

tim ab0wr

On Thu, 26 Apr 2018 08:44:39 -0700
"Kees T" <windy10605@...> wrote:

It appears that the ND6T implementation of an AGC fix for the uBIT-X
is a winner. 

He describes a simple X-Acto knife cut PC board for layout. Is anyone
thinking of providing a small 2 sided PC board w/wo all the parts ?

73 Kees K5BCQ

Re: ND6T AGC implementation for uBIT-X

Jerry Gaffke
 

Yes, you have plenty of experience with this.
There've been discussions in this forum before about what can and can't get posted in a letter,
so figured I'd say what little I knew for the benefit of the other kit creators.

Lots of very nice kits up at http://www.qsl.net/k5bcq/Kits/Kits.html
including linear amps, bandpass filters, and of course the Vector Impedance Analyzer.
I need to place an order for a couple of your step attenuators, since I'm slowly getting serious
about figuring out EMRFD.

Jerry, KE7ER


On Thu, Apr 26, 2018 at 12:35 pm, Kees T wrote:
Jerry, I believe I can get all those parts in a standard envelope and mail it for $0.50. I've done it before.

Re: ND6T AGC implementation for uBIT-X

Ken
 

Heck I'll pay the extra postage ($10,000,000.00 CAD) to get it here.

73 

Ken VA3ABN

On Thu, Apr 26, 2018 at 3:57 PM, Kees T <windy10605@...> wrote:
Ken,

Canada eh  ....sure, as long as postage is covered. Will require a customs short form. Since starting this low buck kit activity, after retirement in 1998, I've shipped 3987 kits as of today, all over the world. 

Waiting to see what Ion, VA3NOI is wanting to do and what Don, ND6T says since it's his design and all questions, accolades, gripes, blame, etc.  go back to him (and it's his call that would be silkscreened on the board). 

I like Jerry's comment;     "That sounds great! I for one would be happy enough at $10 if it saves me a day of messing around 
with Mouser orders and Xacto knife emergency room visits."

73 Kees K5BCQ