Date   
Re: Creating Gerber files for pcb construction

Diver Martin <diver.martin@...>
 

I'm blown away by Easyeda's PCB pricing... I don't think any service I've used can touch that price.  I just paid last week $105 for 10 PCB's for my uBitx top motherboard with DFRobot, designed around a 150mm x 200mm maximum PCB size (including shipping).  EasyEDA quotes $38 for the same thing (not including shipping, which I assume to be $15-20).  WIsh I had known a week earlier, I would have tried them out, unsure about their quality.  (DFRobot does good quality)

I'm a big kicad fan, use it for 6-layer large-scale loadboards on 4.0 stable.  I'm eagerly awaiting the next 5.0 (or whatever it will be called) release for more 3D component support via STP files/etc.  The daily builds look very promising.

On Mon, Jan 15, 2018 at 12:09 PM, Mike Bryce <prosolar@...> wrote:
Guys….


first off Easyeda does not need to be done on line. All you need is the gerber files generated by any number of layout programs. 

I use DipTrace and Easyeda all the time.

I DO NOT use their on line software for board layout.

The price point is making a board equal to or less than 100 mm square. If you can, 10 pcs at Easyeda will set you back $2.

yup! Two bucks!

of course there is shipping and DHL is $12 and change.

or slow boat from China for about $6


Yesterday I ordered 10 pcs of 6.5 by 1.5” boards and they were $11 and change for the the lot. This exceeded the 100 mm size, but still that’s not a bad price.


One of the secrets I’ve discovered is lumping all your pcb orders into one. Not, repeat NOT all the gerber files on one pcb, but rather send four or five separate files.( or as many has you have) The shipping will be dramatically reduced.

When I did the order the other day, I had five unique files, 10 pcbs each order, and the shipping via DHL was $23 and change.
So, 50 pcs shipped for $11 more than a single order.

all the chinese pcb houses, and OSH park require what is know as a board outline file. 

In the gerber, it’s called, ‘boardname. GKN’

OSH is great for smaller pcbs, and they’re made in the USA. However, when the pcb size begins to scoot upwards, they become dearly expensive. They offer as standard gold flashed pads, and of course the pcbs are purple.

Many of the USA based pcb houses kind of cheat and send small run orders to china. 




On Jan 15, 2018, at 2:46 PM, N7PH <hickspj467@...> wrote:

James,

Most places also require a Board Dimension file. Perhaps OSHPark grabs that file on their own when they generate the Gerbers or it is available from one of the other files.

I have looked at several Gerber files and they appear to be CNC type G-code files with some special codes.

PJH, N7PH




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Re: Programming Raduino help

Jack, W8TEE
 

I'm not sure about Win 10, but loading/installing the drivers directly might be worth a try. Go to the directory where you installed the Arduino IDE. Look in the Drivers subdirectory for:

dpinst-amd64.exe

and run it. It will look for the required drivers and install any missing ones if it can. Now, close (if open) and reload the IDE and see if the port is there. The board you are looking for is the Nano, not Uno.

Jack, W8TEE



From: Vic WA4THR via Groups.Io <vhklein@...>
To: BITX20@groups.io
Sent: Monday, January 15, 2018 3:26 PM
Subject: [BITX20] Programming Raduino help

OK, this is new territory for me, so I was using "Raduino Software Instructions for Geezers" and stepping through the process to upload Amunters v1.27.6 to the Raduino in my new Bitx40. I got as far as selecting the proper port using the Aduino IDE 1.8.5 software and using Tools looked for which one was the Raduino or Aduino. None of them are so indicated on my Win10 machine. COM pports 1-4 are shown and reflect that I have a card that gives me 4 DB9 serial ports for controlling other equipment, and Ports 5 and 6 show up as well. Port 6 gets "grayed out" if I pull the USB from the Raduino, so I assume that is it, but nothing indicates that it is. I tried following instructions on the software for the Arduino IDE program as follows:

  • Click on the Start Menu, and open up the Control Panel.
  • While in the Control Panel, navigate to System and Security. Next, click on System. Once the System window is up, open the Device Manager.
  • Look under Ports (COM & LPT). You should see an open port named "Arduino UNO (COMxx)". If there is no COM & LPT section, look under "Other Devices" for "Unknown Device".
  • Right click on the "Arduino UNO (COmxx)" port and choose the "Update Driver Software" option.
  • Next, choose the "Browse my computer for Driver software" option.
  • Finally, navigate to and select the driver file named "arduino.inf", located in the "Drivers" folder of the Arduino Software download (not the "FTDI USB Drivers" sub-directory). If you are using an old version of the IDE (1.0.3 or older), choose the Uno driver file named "Arduino UNO.inf"
  • Windows will finish up the driver installation from there.

Again, nothing in the control panel shows the device is an Arduino or Raduino. Instead it is identified as "USB-Serial CH340". Nothing in the details suggests it is an Arduino, either, so I cannot update the software. Otherwise the Raduino 1.01 software is indicated on the LCD when it boots up, but I am frankly afraid to try to upload something else lest it will wipe out the current workability altogether.

Is this what I should be seeing, am I missing something here?

=Vic=
WA4THR


Programming Raduino help

Vic WA4THR
 

OK, this is new territory for me, so I was using "Raduino Software Instructions for Geezers" and stepping through the process to upload Amunters v1.27.6 to the Raduino in my new Bitx40. I got as far as selecting the proper port using the Aduino IDE 1.8.5 software and using Tools looked for which one was the Raduino or Aduino. None of them are so indicated on my Win10 machine. COM pports 1-4 are shown and reflect that I have a card that gives me 4 DB9 serial ports for controlling other equipment, and Ports 5 and 6 show up as well. Port 6 gets "grayed out" if I pull the USB from the Raduino, so I assume that is it, but nothing indicates that it is. I tried following instructions on the software for the Arduino IDE program as follows:

  • Click on the Start Menu, and open up the Control Panel.
  • While in the Control Panel, navigate to System and Security. Next, click on System. Once the System window is up, open the Device Manager.
  • Look under Ports (COM & LPT). You should see an open port named "Arduino UNO (COMxx)". If there is no COM & LPT section, look under "Other Devices" for "Unknown Device".
  • Right click on the "Arduino UNO (COmxx)" port and choose the "Update Driver Software" option.
  • Next, choose the "Browse my computer for Driver software" option.
  • Finally, navigate to and select the driver file named "arduino.inf", located in the "Drivers" folder of the Arduino Software download (not the "FTDI USB Drivers" sub-directory). If you are using an old version of the IDE (1.0.3 or older), choose the Uno driver file named "Arduino UNO.inf"
  • Windows will finish up the driver installation from there.

Again, nothing in the control panel shows the device is an Arduino or Raduino. Instead it is identified as "USB-Serial CH340". Nothing in the details suggests it is an Arduino, either, so I cannot update the software. Otherwise the Raduino 1.01 software is indicated on the LCD when it boots up, but I am frankly afraid to try to upload something else lest it will wipe out the current workability altogether.

Is this what I should be seeing, am I missing something here?

=Vic=
WA4THR

Re: Creating Gerber files for pcb construction

Mike Bryce
 

Guys….


first off Easyeda does not need to be done on line. All you need is the gerber files generated by any number of layout programs. 

I use DipTrace and Easyeda all the time.

I DO NOT use their on line software for board layout.

The price point is making a board equal to or less than 100 mm square. If you can, 10 pcs at Easyeda will set you back $2.

yup! Two bucks!

of course there is shipping and DHL is $12 and change.

or slow boat from China for about $6


Yesterday I ordered 10 pcs of 6.5 by 1.5” boards and they were $11 and change for the the lot. This exceeded the 100 mm size, but still that’s not a bad price.


One of the secrets I’ve discovered is lumping all your pcb orders into one. Not, repeat NOT all the gerber files on one pcb, but rather send four or five separate files.( or as many has you have) The shipping will be dramatically reduced.

When I did the order the other day, I had five unique files, 10 pcbs each order, and the shipping via DHL was $23 and change.
So, 50 pcs shipped for $11 more than a single order.

all the chinese pcb houses, and OSH park require what is know as a board outline file. 

In the gerber, it’s called, ‘boardname. GKN’

OSH is great for smaller pcbs, and they’re made in the USA. However, when the pcb size begins to scoot upwards, they become dearly expensive. They offer as standard gold flashed pads, and of course the pcbs are purple.

Many of the USA based pcb houses kind of cheat and send small run orders to china. 


On Jan 15, 2018, at 2:46 PM, N7PH <hickspj467@...> wrote:

James,

Most places also require a Board Dimension file. Perhaps OSHPark grabs that file on their own when they generate the Gerbers or it is available from one of the other files.

I have looked at several Gerber files and they appear to be CNC type G-code files with some special codes.

PJH, N7PH

Re: preorder question #ubitx

w2ttt <w2ttt@...>
 

I ordered on 20180109, so I'm guessing that it will be at least a month before DHL brings me mine!
Keep us posted on order/ship dates.
73,
Gordon Beattie,  W2TTT
201.314.6964





On Mon, Jan 15, 2018 at 2:24 PM -0500, "August Treubig" <atreubig@...> wrote:

Mine delivered today.   A day early.
Aug
AG5AT

Re: #ubitx Re: Ubitx only on preorder now #ubitx

VU3ECN
 

Thanks for  remembering me Mr Sarma. I hope the Diodes I sent you reached you in finally. I hope to get y license this Year , so looking forward to build a Rig in the meanwhile.  As I see uBitx is a semi commercial Enterprise of Mr  Ashhar and his friends. But is this otherwise "Open Hardware" ? Like could I design my Version of PCB and try to build it ? I would love to slowly design the PCB over the time for the sheer joy of building and tuning the Rig.
Looking forward to hear more from you.

73s

Ujjwal 

Re: Creating Gerber files for pcb construction

N7PH <hickspj467@...>
 

James,

Most places also require a Board Dimension file. Perhaps OSHPark grabs that file on their own when they generate the Gerbers or it is available from one of the other files.

I have looked at several Gerber files and they appear to be CNC type G-code files with some special codes.

PJH, N7PH

Re: irf520 vs irf510

Diver Martin <diver.martin@...>
 

I think I mentioned it before, but anyone seeking to drop in a Mitsubishi RDMos part should be aware that 

a) They're designed for 12V operation.  You won't want to run them at 18V/etc
b) They have a different pinout, you'll have to solder them in with the leads mangled/crossed.  IRF510/20/30's are Gate-Drain-Source.  The RDMos series are Gate-Source-Drain.  This is a mod I still intend to try at some point, but have other projects on the plate first.
c) They have a different bias voltage.  Turn down the bias voltage before you key up, and then re-bias appropriately. If your IRF510's are biased at something like 4V when the bias voltage for the RDmos's are 2V (I'm making total wild assumptions, it could be the other way around), you'll instantly turn the devices on full-current and potentially blow something up.  
d) The feedback network will want to be different.  These have much more gain at high frequencies.  You may need more negative feedback.
e) You can use an uninsulated grounded heatsink, as the tabs of the these devices is the source and not drain.

I'm looking forward to hearing from someone who's done the mod and tried it out.

On Mon, Jan 15, 2018 at 10:52 AM, Tim Gorman <tgorman2@...> wrote:
Dave,

Would this be a satisfactory drop-in replacement? I can't find any info
on input or output capacitance to compare it to an irf510.

From the Smith chart on the datasheet I'm guessing the input
capacitance is about 60pf (been a long time since I've used a Smith
Chart) at 30Mhz, much less than the irf510. Would that impact the
negative feedback used on the amp significantly (0.1uf in series with a
220ohm resistor)?

By the same token the output capacitance would appear to be much higher
than the irf510. I suspect that will impact the design of the bandpass
filters but I'm not sure by how much without doing a lot of
calculations.

I'm just looking for something that would provide more reliability
under adverse conditions (e.g. high swr) than the irf510. Don't really
care if it provides higher output or not - but that might come later
<grin>.



On Sun, 14 Jan 2018 22:51:06 -0800
"Dave Bottom" <ars.kd6az@...> wrote:

> Or the Mitsubishi RF RD16HHF1 MOSFET designed for 2-30MHz RF
> applications. Under $5 each.  Or the RD16HVF1 only pennies more and
> good through 2M.
>
> With a 12VDC to 24/28VDC DC to DC converters (about $4) and the Mitsu
> parts can be bolted directly to a big heatsink attached to the
> chassis, no insulator required.
> Probably good for 20W through 10M although run off batteries a bit
> shorter battery life.  At real 5W QRP they should be happy forever.
>
> Dave WI6R
>
> On Sun, Jan 14, 2018 at 4:33 PM, Tim Gorman <tgorman2@...> wrote:
>
> > All,
> >
> > Looking to order some spare output finals for the ubitx I have on
> > order.
> >
> > In looking around the IRF520 appears to have higher ratings than the
> > IRF510 with a lower Rds.
> >
> > The 510 does have much lower input and output capacitance.
> >
> > There is hardly any difference in price.
> >
> > Any recommendations on which to order?
> >
> > tim ab0wr
> >
> >
> >
> >
>
>







--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Re: preorder question #ubitx

 

Mine delivered today.   A day early.
Aug
AG5AT

Re: Creating Gerber files for pcb construction

James Lynes
 

Gordon:

I've just had my first PCBs manufactured by OSHPark. Their fee is $5 per square inch(for three boards) with free shipping. It took about 15 days to receive the boards. They provide a lot of status updates during the order processing.

Gerber files are actually seven files: top layer, bottom layer, solder stop top, solder stop bottom, silk screen top, silk screen bottom, and drill.

I used the free version of Eagle(board limit about 3" x 4"). An added benefit of OSHPark is that all they need is the Eagle .brd file. They make the Gerbers and panelize the orders onto 18" x 24" boards for manufacturing.

I recommend the Simon Monk book "Make Your Own PCBs with Eagle". It contains very useful information on installing the Adafruit and Sparkfun libraries and the Sparkfun design rules. I made myself a cheat sheet that I think will be published in the next QRP Quarterly.

James

Re: PCB layout s/w

Rod Davis
 

Jerry, and all

About a year ago I went through the overhead of learning both Kicad and Eagle to see which I would want to use.

My vote is firmly in the Eagle camp. I found Kicad to be laborious and awkward. However, one strong point about Kicad is you can layout arbitrary trace shapes. Not sure Eagle can do that, but Eagle is SO much easier to use. Lotsa component libraries available for Eagle.

Eagle runs directly on Linux, and Windows, as well.

Just my read on the situation, YMMV

Rod KM6SN



On 01/15/2018 09:39 AM, Jerry Gaffke via Groups.Io wrote:
Haven't been keeping up much on the new board layout tools available, will be watching this thread closely.

I'm retiring as well.  
Much of my professional work revolved around PadsPCB (now owned by Mentor), doing tight 10 layer boards with large BGA's.
Can't recommend PadsPCB, not cheap or easy, primary selling point for us was the UI hadn't changed much since the 1980's.
Kicad is complex and a bit rough around the edges, but looks like it should give comparable results.
The Bitx40 and uBitx were created under kicad.
I can run it under linux which is a major plus as I'd prefer to avoid anything Microsoft.
Files are ascii text rather than binary blobs, netlisting and such done with easily hacked python scripts.
Open source, so it won't become unavailable or unusable or spendy like Eagle or CopperConnections.
It's being actively developed by the folks at CERN

EasyEDA looks interesting, though my situation demands offline use so won't work for me.
Could be ideal for casual hobbyist use.
But don't tell expressPCB.

Jerry, KE7ER

Re: Creating Gerber files for pcb construction

August Johnson
 

I've had excellent results using KiCad to design and http://www.allpcb.com/ to produce boards. Just had some 4"x6" double-sided plated thru w silk screen and solder mask boards made. $33.44 total (Including $1.44 for PayPal payment) for 5 boards including free DHL shipping. They actually sent 8 boards instead of the 5 I ordered. From the reviews I see, people often get more than they ordered. Ordered on Monday evening and delivered on Saturday. Would have been a day sooner but DHL doesn't deliver to my town and had to wait one more day for USPS delivery.

August KG7BZ

Re: Creating Gerber files for pcb construction

Jack, W8TEE
 

I had trouble with the link...way too large and a popup in the middle. If you delete the "m." in


it's a little easier to read.

Jack, W8TEE


From: Art Howard <k0kuk.vhf@...>
To: BITX20@groups.io
Sent: Monday, January 15, 2018 1:10 PM
Subject: Re: [BITX20] Creating Gerber files for pcb construction

Not sure where to post this but I had a friend of mine doing some astronomy project and needed boards with parts are assembled and so forth because he's not technically able to do that.
 I do not know a lot about this stuff myself but his boards with the assemble parts and stuff were about 50 to 60% cheaper than anybody else had them so I'm not sure if it's relevant for anybody wanting to make the modifications to the UbitX etc.
 Here is a link to that outfit that does boards and assembly units and so forth and would be interested in knowing if somebody that's knowledgeable could check it out and see if they really are that much cheaper ?

On 15 Jan 2018 10:04 am, "Gordon Gibby" <ggibby@...> wrote:
Haven't been keeping up much on the new board layout tools available, will be watching this thread closely.

I'm retiring as well.  
Much of my professional work revolved around PadsPCB (now owned by Mentor), doing tight 10 layer boards with large BGA's.
Can't recommend PadsPCB, not cheap or easy, primary selling point for us was the UI hadn't changed much since the 1980's.
Kicad is complex and a bit rough around the edges, but looks like it should give comparable results.
The Bitx40 and uBitx were created under kicad.
I can run it under linux which is a major plus as I'd prefer to avoid anything Microsoft.
Files are ascii text rather than binary blobs, netlisting and such done with easily hacked python scripts.
Open source, so it won't become unavailable or unusable or spendy like Eagle or CopperConnections.
It's being actively developed by the folks at CERN

EasyEDA looks interesting, though my situation demands offline use so won't work for me.
Could be ideal for casual hobbyist use.
But don't tell expressPCB.

Jerry, KE7ER



Virus-free. www.avast.com

Re: irf520 vs irf510

Tim Gorman
 

Thanks for the reply, John. I'll stock up on irf510's!

tim ab0wr

On Sun, 14 Jan 2018 16:55:50 -0800
"John Backo" <jabac@...> wrote:

Tim:

Given the druthers, stick with the IRF510.

Yes, the IRF520 and IRF530 have better voltage stats,
but much higher input gate capacitance. This DOES
make a difference. Remember, these devices were
designed for low frequency switching operations. They
were designed for on/off operation.

Adapting them to RF is another ball game entirely.
Input and output capacitance do matter...a great deal.

But the IRF520 has been adapted successfully to PA
operation (they are in a lot of Chinese amps). So it
can be done...but adjustments have to be made, usually
by increases negative feedback. The IRF530 is MUCH
harder to work with. Yeah, it can be done but keeping it clean is a
real pain...

Operating the IRF510 on 18-24v (or more up to 48v)
will give very good results provided it is done right and attention
is paid to heat generation and impedance.

john
AD5YE


Re: irf520 vs irf510

Tim Gorman
 

Dave,

Would this be a satisfactory drop-in replacement? I can't find any info
on input or output capacitance to compare it to an irf510.

From the Smith chart on the datasheet I'm guessing the input
capacitance is about 60pf (been a long time since I've used a Smith
Chart) at 30Mhz, much less than the irf510. Would that impact the
negative feedback used on the amp significantly (0.1uf in series with a
220ohm resistor)?

By the same token the output capacitance would appear to be much higher
than the irf510. I suspect that will impact the design of the bandpass
filters but I'm not sure by how much without doing a lot of
calculations.

I'm just looking for something that would provide more reliability
under adverse conditions (e.g. high swr) than the irf510. Don't really
care if it provides higher output or not - but that might come later
<grin>.



On Sun, 14 Jan 2018 22:51:06 -0800
"Dave Bottom" <@WI6R> wrote:

Or the Mitsubishi RF RD16HHF1 MOSFET designed for 2-30MHz RF
applications. Under $5 each. Or the RD16HVF1 only pennies more and
good through 2M.

With a 12VDC to 24/28VDC DC to DC converters (about $4) and the Mitsu
parts can be bolted directly to a big heatsink attached to the
chassis, no insulator required.
Probably good for 20W through 10M although run off batteries a bit
shorter battery life. At real 5W QRP they should be happy forever.

Dave WI6R

On Sun, Jan 14, 2018 at 4:33 PM, Tim Gorman <tgorman2@...> wrote:

All,

Looking to order some spare output finals for the ubitx I have on
order.

In looking around the IRF520 appears to have higher ratings than the
IRF510 with a lower Rds.

The 510 does have much lower input and output capacitance.

There is hardly any difference in price.

Any recommendations on which to order?

tim ab0wr



Re: Microphone frequency response

MVS Sarma
 

 we can use Maxim MAX7400 to limit the Mic Bandwidth. It is good Chip , costly though.

regards
 sarma
 vu3zmv

Regards
MVS Sarma
 

On Mon, Jan 15, 2018 at 11:51 PM, bill richardson <ng1p.bill@...> wrote:
Thanks Allard.. I’ll try upgrading to v2. I have done all the mods in the v1 track so it’s worth a try. I did put a variable cap to manually adjust the BTO but my audio was still favoring the lows. 

Sent from my iPhone

On Jan 15, 2018, at 1:14 PM, Allard PE1NWL <pe1nwl@...> wrote:

On Mon, Jan 15, 2018 at 10:05 am, Arv Evans wrote:
I would first look at BFO versus filter passband as a possible
solution
With the arduino v2 software (https://github.com/amunters/bitx40-raduino-v2) you can easily correct the BFO frequency.
A minor modification (https://github.com/amunters/bitx40-raduino-v2/blob/master/digital%20BFO%20mod.png) is required for this software.

73 Allard PE1NWL


Re: tx pop

Ryhor Harbacheuski
 

in my hands even simper elegant circuit borrowed from QCX transceiver
takes care of the pop completely, see attached.
with 300K R and 440nf C timing is just right to keep BS170 open long
enough when switched back to RX.
AF CW self control tone gets weaker with this, however in my uBITX
board 10K R253 was geniusly replaced by 1K, so this
makes CW tone loud enough with this mod.
Greg W3NW


On Mon, Jan 15, 2018 at 8:32 AM, ve7hcw via Groups.Io
<ve7hcw=yahoo.ca@groups.io> wrote:
It's the current charging and discharging of C50 and c63 cause the modulator
diodes to conduct whereas after initial stabilization of the capacitor
charges by keeping the mic preamp and receiver preamp powered up by
connecting directly to the power supply. Then the AC audio is switched in
by the MOSFETs which has not change in DC will not create pulse pop. Last
year I had a similar problem with a commercial product I build for PA
system with mike pops on/off because of charging and discharging
capacitors. I did the same and leave the mike circuit active but use a
MOSFET to isolate the AC sound when OFF and switch ON by powering the
MOSFET. No DC was switched by the MOSFET only AC result in no clicks and
pops.
The 100k resistors in the drain side of the MOSFET is to bleed the
charge and stablilize the steady charge on the capacitors. The other 100k on
the MOSFET source side is to make sure the gate has a charge reference to
make the MOSFET work doing switching.
W

Re: Compiling and uploading uBITX firmware #ubitx

Arv Evans
 

Tilman SM0JZT

Warning messages can usually be ignored as long as they do not stop the compile. 
In the situation you indicated, the up-arrow "^" points to the character where it found
something different from more modern implementation of C++ language.

Arv  K7HKL
_._


On Mon, Jan 15, 2018 at 5:24 AM, Tilman D Thulesius <sm0jzt@...> wrote:
Thank you so very much guys !

I think I got it now and have compiled som code. with successfull results. 

Got a number of "errormessages" with "deprecated conversion" during compilation. Here a example. :
 
d:\tilman\Arduino\uBITX_20\ubitx_menu.ino:515:18: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
 
     printLine2("");  
 
                  ^

The bottom line after verification is though :

Sketch uses 16104 bytes (49%) of program storage space. Maximum is 32256 bytes.
Global variables use 1376 bytes (67%) of dynamic memory, leaving 672 bytes for local variables. Maximum is 2048 bytes.

So I guess that is good news and I dare to upload to my uBITX ?

Im not at all a C-coding guru a any length as you imagine. How are the different pieces of code interlinked with each other ?? Im trying to find references in the "ubitx_20" to the other files. But nothing....... 

Please enlighten me on this.

Thank you in advance SM0JZT - Tilman
 


Re: uBitx Low level audio output.

Jerry Gaffke
 

The first pass at a uBitx schematic used the second TDA2822 channel for AGC:
    http://www.phonestack.com/farhan/ubitx/ubitx.html

On the uBitx boards being shipped, that AGC implementation has been disabled.
You are free to use the second channel for something else.

Jerry, KE7ER


On Mon, Jan 15, 2018 at 09:49 am, Max Lock wrote:
The onboard TDA2822 is a stereo amp, although it looks like both channels are used. Is it worth trying to change that or just tap the audio from some where near M2 (R70) and amplify it separately?

Re: Matched xtals #ubitx #bitx40

Gordon Gibby <ggibby@...>
 

​Arv, thanks for the input!!!    I may give this a whirl sometime!!!

gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Arv Evans <arvid.evans@...>
Sent: Monday, January 15, 2018 1:21 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Matched xtals #bitx40 #ubitx
 
Gordon

Not necessarily.  Most modern homebrewed crystal filters use same-frequency crystals
but the concept of "same frequency" is not really super critical.  All within 100 Hz is more
than adequate for most builds.  The concept of staggering crystal frequencies comes
from the past when we built up lattice-filters using staggered crystal frequencies and no
interstage tuning capacitors.

Bandwidth of your ladder filter is mostly controlled by the interstage capacitors to ground.
Impedance in and out is mostly controlled by the input and output coupling capacitors.
(transformers can also be used for impedance matching).

Input and output impedance mis-match will usually be seen as ripple in the passband and
possibly higher insertion loss.

While it is very convenient to use a swept frequency source and CRT based output
level display, you can use a stable oscillator that can tune in 100 Hz steps and a
simple diode detector and meter to test crystal filter bandwidth and shape factor.
To do this take output level measurements at 100 Hz intervals and log these on
graph paper (or in a spreadsheet) as frequency versus voltage.  Note that pure voltage
measurements will show higher resolution that will plotting these measurements in log
format.  Most crystal passband charts show the result in log format. 
When doing crystal ladder filter tests it is important that the test layout provide proper
impedance matching for input and output ports.


Arv  K7HKL
_._


On Mon, Jan 15, 2018 at 2:51 AM, Gordon Gibby <ggibby@...> wrote:
OK, so newbie question here. If you’re trying to make a filter of about 2 kHz bandwidth, do you need to have all these crystals with in 100 Hz of each other?   

I would’ve thought that would have made an extremely narrow filter.

Or in order to make the filter 2 kilohertz wide, do you need them scattered about  a 2khz distribution?

Thanks!

Sent from my iPhone

On Jan 15, 2018, at 03:19, Mvs Sarma via Groups.Io <mvs_sarma@...> wrote:

last month I had some 9MHz crystals from an ebay seller.
 Ther e marked "H12.000" and are HC-49/s. Out of 20, i could match 15 with in 100Hz.

 The same guy has also 12MHz . please contact him ans seek crystals marked "H12.000"
  Here is the link from whom i bought i selected 12MHz  for meet your need.



regards
 sarma
 vu3zmv


On Sunday 14 January 2018, 12:55:58 AM IST, KM4TRT via Groups.Io <garello@...> wrote:


Actually a total of 9 matched for 12 mhZ