Date   
Re: KD8CEC Firmware

 

Charlie :

You will need to add the two additional resistors if you want to use paddles on CW with the KD8CEC firmware.

Also you would require a hardware mod for the S-meter functionality on the 2.8" display to work.

Other features like IF-Shift and ATT don't require any additional mods to rig. 

I will let you know if there is anything else.

Saturday is Field Day here in NA so I will busy, but I hope to get my
new display up and running on Sunday. 

Cheers

Michael VE3WMB 

Re: ND6T AGC and Click kit wiring notes

Mark M
 

Hmmm...I've had some issues with mine. I wonder if I may have reverse powered it before I realized the pad by the 5V marking was ground. I don't imagine that would be good for it.

I guess I could build the second one I have & see if it makes any difference. Or maybe just replace the transistors.

Mark  AA7TA

Re: experience with Sunil VU3SUA's enclosures #ubitx

allen west
 

My only complaint about the case is there are no bare spots for grounding. Also no star washers for grounding. Apparently case ground was not an issue.

I really do like the looks and sturdiness.

Al
KB4RA

On Jun 22, 2018, at 8:53 PM, Mark M <junquemaile@...> wrote:

I had fitting issues as well. First off I used the short standoffs to mount the board (doh!) so it was WAY off. One I figured out it needed the longer standoffs it was about 2mm off side-to-side. I used a small round file to elongate the holes by about that much to the right (as you look at it from the front) and it fits OK now.

My main complaint is that some of the components aren't real high quality (mainly the phone jacks and the power connector). The on/off switch doesn't work.

All in all, I can't complain too much. A blank box from other suppliers would be $20-$25 and you'd have to supply your own connectors, hardware, etc, plus have to drill], paint, & label it.

As always, YMMV...

Mark AA7TA

On 6/22/18 3:58 PM, Ken Held KF7DUR via Groups.Io wrote:
I paid extra for DHL and the case took less then 6 weeks to arrive.
Has anyone else had a problem with the LCD display not fitting properly in the front cutout. Mine is way off, the LCD would need to move up and to the right (by one pin) for a proper fit.
I'm not very impressed with this case.
_._,_._,_

Re: Nextion Displays >> warning

 

I followed Joe's (VE1BWV) lead and checked out Robotshop.ca and found the 2.8" display for about $25 CAN.
This is a pretty reasonable deal and it showed up in a couple of days. We will see how long it takes for the 2.8"
display that I had previously ordered on eBay (coming from China) takes to show up ! 

Michael VE3WMB 

Re: Understanding Spurious Emissions

Tim Gorman
 

If all I need is to use the ubitx as a 28Mhz IF for a 2m transverter
then all I need is a 28mhz high-pass, correct?

I would think that it would be easy enough to build a high-pass in order
to kill the 16mhz-17mhz spur. Perhaps build it into the transverter
itself.

Any recommendations?

tim ab0wr

On Fri, 22 Jun 2018 18:02:01 -0700
"ajparent1/KB1GMX" <kb1gmx@...> wrote:

If we use round numbers...

45mhz - dial frequency= spur

For 28 to 29mhz the spur is 17 to 16mhz
For 24.830 to 24.990mhz the spur is 20.17 to 20.01 mhz 
For 21.2 to 21.45mhz the spur is 23.8 to 23.55mhz 

For 10 and 12 if one can devise a suitable high pass  that attenuates
everything below 21mhz it can work....  I ran a 9pole filter and it
did not work well enough as in it either kills 24.9 or it doesn't
kill the 20.17 spur much.  Possibly a Caur or elliptical filter would
but they will be touchy to make.

Not matter what one filter can't do it all.  Though 28mhz is the
easiest as the spur is further away.

Triple tuned band pass can, models were tried and maybe a double
tuned might.

I do know that a triple tuned filter for 28 to 29 mhz was effective.
Phone (SSB) is frm 28.3 to not much over 28.8 and for techs its only
28.3 to 28.5.  It would have to pass down to 28.0 for CW.

The 15M filter is a tough nut as the spur is close at 23.55 when at
21.45. That would require a triple tuned filter of some quality.  If
it lowers the spur by 20db it would do the job with a little excess.
It would be a very good filter to do that.

Allison


Re: Understanding Spurious Emissions

Jerry Gaffke
 

Table two of the arrl.org filter reference shows that the 21 mhz bandpass filter 
has 15db of attenuation at 28mhz, that's 7mhz away.
We need something like 20 dB of attenuation at 2mhz away.
As Allison says, that's a tough nut to crack.

And I have my doubts about the filter I pointed to.

Jerry


On Fri, Jun 22, 2018 at 04:31 pm, Gordon Gibby wrote:
Forgot to put the link.
 
 

Re: Understanding Spurious Emissions

Jerry Gaffke
 

I'd recommend you check to see if the transverter takes care of the spur for you.

At 28mhz, the spur is at 45-28=17mhz going in, and something around 30 dB down from your 28mhz signal.
The transverter likely does all the filtering you need already.

If you need additional filtering, a 28mhz highpass would do it.

Jerry


On Fri, Jun 22, 2018 at 06:19 pm, Tim Gorman wrote:
If all I need is to use the ubitx as a 28Mhz IF for a 2m transverter
then all I need is a 28mhz high-pass, correct?

I would think that it would be easy enough to build a high-pass in order
to kill the 16mhz-17mhz spur. Perhaps build it into the transverter
itself.

Any recommendations?

measuring spurious signals

Arv Evans
 

The various BITX transceivers present an interesting and educational opportunity to
determine the accuracy of our test equipment, test procedures, and interpretation
of all the above. 
It seems imperative that the test gear be configured and verified that measurements
are accurate and reflect just the contribution from the DUT, and not something from 
test equipment.  Attenuators and filters are necessary to insure that we are measuring
what we think we are measuring. 

Arv
_._

Re: Understanding Spurious Emissions

William Kimber
 

On 21Mhz rather than a band pass/high/low filter what about 23mhz trap(s) also called notch filter. Even high Q should be wide enough to cover whole 23.8 to 23.55Mhz.   Similar for  24Mhz   needs to cover 20.17 to 20.01Mhz


Cheers,

Will

ZL1TAO


On 23/06/18 13:33, Jerry Gaffke via Groups.Io wrote:
Table two of the arrl.org filter reference shows that the 21 mhz bandpass filter 
has 15db of attenuation at 28mhz, that's 7mhz away.
We need something like 20 dB of attenuation at 2mhz away.
As Allison says, that's a tough nut to crack.

And I have my doubts about the filter I pointed to.

Jerry

On Fri, Jun 22, 2018 at 04:31 pm, Gordon Gibby wrote:
Forgot to put the link.
 
 

Re: Understanding Spurious Emissions

Ashhar Farhan
 

I am not sure if 28 mhz is a problem. I am travelling so I will go back and check. I switched to 4 filters to be fcc compliant from 3.5 mhz to 28 mhz. 
- f

On Sat, 23 Jun 2018, 07:16 William Kimber, <zl1tao@...> wrote:

On 21Mhz rather than a band pass/high/low filter what about 23mhz trap(s) also called notch filter. Even high Q should be wide enough to cover whole 23.8 to 23.55Mhz.   Similar for  24Mhz   needs to cover 20.17 to 20.01Mhz


Cheers,

Will

ZL1TAO


On 23/06/18 13:33, Jerry Gaffke via Groups.Io wrote:
Table two of the arrl.org filter reference shows that the 21 mhz bandpass filter 
has 15db of attenuation at 28mhz, that's 7mhz away.
We need something like 20 dB of attenuation at 2mhz away.
As Allison says, that's a tough nut to crack.

And I have my doubts about the filter I pointed to.

Jerry

On Fri, Jun 22, 2018 at 04:31 pm, Gordon Gibby wrote:
Forgot to put the link.
 
 

Re: Homebrew from scratch #ubitx

Jack, W8TEE
 

Beautiful!

Jack, W8TEE

On Friday, June 22, 2018, 1:50:24 PM EDT, Peter Carr <radio@...> wrote:


I have just built a uBITX with standard components (no SMD's) from scratch on a PCB I designed - it works well.  I have now designed another PCB which incorporates the Arduino NANO and the the Si5351 shield and I'm just waiting for the PCB's to arrive and then I will start assembling.  I made some changes to the circuit to allow for a dynamic microphone and the use of screened TOKO cols for the 30MHz lowpass filter, I also changed the coupling arrangement to the 45MHz filter.

I have attached a picture of the original PCB and a PDF of the new layout incorporating the Arduino and Si5351

Maybe one day I will play with SMT but for now standard components are still easily available !
 
73's - Peter M0HYT

Re: W8TEE Power/SWR Sketch for Nano

Jack, W8TEE
 

Spend a weekend with a Nano, the OLED, and a breadboard and the example code and you'll have it working in less than a week even if you don't know programming. If I had JackAl tucked away in bed, I'd jump in and help, but I need to finish this up first. Meanwhile, Google "Arduino Nano OLED Projects" and see what pops up. The code is really simple...check the entries out, like:





Jack, W8TEE

On Friday, June 22, 2018, 1:12:20 PM EDT, Kees T <windy10605@...> wrote:


That's the one. We're putting together a 25mW to 25W Power SWR meter (.....like who isn't) and have a great bidirectional coupler, the AD8307s, some Op-Amps as needed for level control and calibration, a Nano, and several of those displays. Makes a nice combination for a uBITX. The only thing I lack is the firmware. We have use those OLEDs in a couple of devices and (if they don't generate too much interference) look very nice and super sharp....FWD, REV, VSWR, ? Could also drive it with one of the many signal generators out there to allow a low level antenna "Tune" function for the attached Transceiver. 

We also have a LED bargraph version which requires NO firmware ....but it's only $2-3 less and lacks being as user friendly. You guys who write the firmware control the road.

73 Kees K5BCQ

Re: Homebrew from scratch #ubitx

 

Very neat Peter!

At 22/06/2018, you wrote:
I have just built a uBITX with standard components (no SMD's) from scratch on a PCB I designed - it works well. I have now designed another PCB which incorporates the Arduino NANO and the the Si5351 shield and I'm just waiting for the PCB's to arrive and then I will start assembling. I made some changes to the circuit to allow for a dynamic microphone and the use of screened TOKO cols for the 30MHz lowpass filter, I also changed the coupling arrangement to the 45MHz filter.

I have attached a picture of the original PCB and a PDF of the new layout incorporating the Arduino and Si5351

Maybe one day I will play with SMT but for now standard components are still easily available !

73's - Peter M0HYT

Heat sink

VE7CWS WRSeiler <waltrseiler@...>
 

Hello fellow constructors

I have been thinking about using a common heat sink for the RF power transistors, insulated with mica washers of course and insulated mounting hardware. Would there be inter capacitance issues or some other anomaly. Any thoughts or experience based 
observations?

cheers and 73

Walt R VE7CWS

Re: Understanding Spurious Emissions

Jerry Gaffke
 

The four transmit filters we have are all low pass filters.
The spur Allison found is below the operating frequency, so those filters don't touch it.

When operating at 28mhz, the spur is at 45mhz - 28mhz = 17mhz

As I understand it, what's happening is the mixer at T1,T2 works as you might expect, 
with the 45mhz IF being converted to 28 mhz by a 45+28 = 73 mhz VFO from clk2. 
But a little bit of that outgoing 28 mhz energy finds its way back into the mixer.
On this second time through it mixes again with the 45mhz IF and we get 45-28 = 17mhz.   
There are plenty of other products like this, but this is the only strong one that's low enough
to get through the 30mhz LPF at L1,2,3,4.

This is not a fault in the way the bat54s mixers are built.
It's just the nature of diode ring mixers, and Allison has found that
she gets the same spur when using commercial mixers while 
carefully controlling impedances at all ports.

Jerry
 


On Fri, Jun 22, 2018 at 07:52 pm, Ashhar Farhan wrote:
I am not sure if 28 mhz is a problem. I am travelling so I will go back and check. I switched to 4 filters to be fcc compliant from 3.5 mhz to 28 mhz. 
 

Re: Heat sink

Jerry Gaffke
 

I believe that should work fine.
Given the significant power and the relatively low voltages,
the impedance at the drain is quite low.  A little bit of extra capacitive coupling
is not too disruptive.


On Fri, Jun 22, 2018 at 09:17 pm, VE7CWS WRSeiler wrote:
I have been thinking about using a common heat sink for the RF power transistors, insulated with mica washers of course and insulated mounting hardware. Would there be inter capacitance issues or some other anomaly. Any thoughts or experience based 
observations?

Re: experience with Sunil VU3SUA's enclosures #ubitx

Mike KK7ER
 

Thanks, everyone, for the comments.  It is great information. Looks like I need to wait a little longer.

73 Mike KK7ER

Re: Blown (socketed) TDA2822?

 

You missed my point Jerry. I am not suggesting 2822D. Please see
the spec sheet I attached. It is a lower power version of tda2822.

I think that die is being repackaged as TDA2822 in 8 pin DIP. It cannot
take the load and blows up.

Raj


At 22/06/2018, you wrote:
Summary:  All is well, unless you have a WX branded TDA2822.


Here's an old post regarding the TDA2822, many other posts in that thread worth browsing:
    https://groups.io/g/BITX20/message/43342

Yes, the TDA2822D is still available from ST, would be a good choice
if you don't mind the 50 mil pin spacing.   I'd stick with the NJM2073.

Re: Blown (socketed) TDA2822?

Jerry Gaffke
 

You think the WX might be a repackaged TA2822D meant for the SOIC8?
I doubt it.
I think the WX is a cheap copy that simply doesn't meet the 15v absolute max spec

We had reports that there are clones of the TDA2822 (not necessarily the WX) 
that blow when given a supply over 7 or 8 volts.  (Some club project in England)
Didn't have to be putting out significant power to blow.
As I recall, some of the WX failures happened instantly, and all struck me as consistent
with too much voltage for it to handle.

The SOIC datasheet you point to has the same 15v absolute max spec
that the DIP part does.

The primary differences I see between the SOIC and DIP datasheets from ST
have to do with power dissipation, possible that ST was using the same die in both
but the SOIC simply can't deal with the heat.
Failure mode on the SOIC would be due to overheating under load and take a bit of time.
I don't think that is what we were seeing with the WX.
 
But I'm just guessing.
Could be proven wrong.

Jerry


On Fri, Jun 22, 2018 at 09:59 pm, Raj vu2zap wrote:
You missed my point Jerry. I am not suggesting 2822D. Please see
the spec sheet I attached. It is a lower power version of tda2822.

I think that die is being repackaged as TDA2822 in 8 pin DIP. It cannot
take the load and blows up.

Re: Blown (socketed) TDA2822?

Jerry Gaffke
 

Would be interesting to pop the lids off the various TDA2822 parts,
examine the die under a microscope.
I'm betting the WX looks significantly different than an ST.


On Fri, Jun 22, 2018 at 10:30 pm, Jerry Gaffke wrote:
But I'm just guessing.
Could be proven wrong.