Date   
Re: RF in 12v Supply

Bill Cromwell
 

Hi Mark,

I laid out and folded a case of steel for my ubitx. Looking from the front, my antenna connector is at the far right rear corner and the internal connector wire is less than two inches long to reach from the board with just a little slack. The DC power connector is over at the far left back. The volume control is way over on the lower right corner of the front panel along with the on-off switch. I routed the power wires under the ubitx board to take advantage of the mostly ground plane board to help shield it from RF at the finals, output filters, and antenna connector. The power line runs much closer to the front of the radio until it gets to the left side and then back. It only comes out from under the circuit board *AT* the back corner. There is no problem with RF. I hope this is helpful to you and others when they layout and assemble theirs.

On 06/29/2018 01:17 PM, Mark M wrote:
The issue discussed in the 'RFI from uBitx TX after AGC and other mods
installed' thread appears to be caused by RF getting into the 12v supply
and from there into the 5v supply that feeds the AGC board (the
ND6T/K5BCQ kit). At least that appears to be the issue on mine. I
thought I'd start another thread to talk about that.

I have the ubitx in a case from amateurradiokits.in. The power comes in
thru a plug in the rear panel at the right of the panel (looking at it
from the front), thru a fuse and then thru three wires twisted together
along the rear panel to the connector on the board at the far left.
There's also a polarity protect diode across the supply. The power
connector is right next to the antenna connector and the supply wires
run past the final transistors and .

I'm running the ubitx on 13.8v from an Astron 20A power supply, The
testing was done feeding a Heathkit Cantenna dummy load.

So, any suggestions on how to fix this would be appreciated. Don
mentioned heavier supply wires and capacitor at the input. I thought I'd
try re-routing the supply wires inside case to get them away from the RF
section. Moving the power connector to the other end of the rear panel
would make the run much shorter. Other than that, I don't know. RF
hardware is not my forte (I'm mostly a software guy).

Thanks.... Mark AA7TA
--
bark less - wag more

Re: Known issues on uBITX r4 #ubitx

Bill Cromwell
 

Hello Hiro,

I understand about the excitement. I had a dreadful time resisting the urge to power mine up on a sheet of cardboard (for insulation) before I formed the case to fit. I did connect power just to confirm whigh way the display had to be mounted :) Murpy's Law you know.

At my shack 'temporary' measures have a habit of becoming more permanent:)

73,

Bill KU8H

On 06/29/2018 12:28 PM, hirosmb JAZZ wrote:
Yes, Bill.

As far as I know, the distortion issue comes up with only v4 ubitx, however it’s just a matter of degree.

I already placed my order with DHL, while taking a train back home today! :)

I also plan to use CEC firmware which I already modified a bit to limit the frequencies to TX in accordance with Japanese regulation.

I compiled the modified firmware which successfully runs on my Arduino UNO now.

Also I ordered a Nextion LCD at eBay which presents really lovely UI/UX.

I don’t think I can sleep properly tonite coz I’m so much excited. :)

Thank you, all of you here who share all the information of ubitx, such a wonderful rig!

// hiro, JJ1FXF



2018/06/30 0:21、Bill Cromwell <wrcromwell@...>のメール:

Hi,

I have V3 with a socketed audio chip labeled as Feb 2018. It worked right out of the box - as advertised. I have not had to make *any* mods at all. I do expect to install the CEC software but that is only to get some options I would like to have for CW. I am already using it for CW. I do not have distirtion, I can tune in SSB and AM stations and they are clear. Lucky me?

Wait until you have actually used your radio to decide if you 'need' mods. Most of the mods I see described are optional and only for the owners perefernces - like my plans to install the CEC software. There will be no hardware changes to mine.

73,

Bill KU8H
--
bark less - wag more

Ubitx receive intermittent

M0CLS
 

Hi, 

The receive on my ubitx has gone very intermittent! One minute everything is coming in strong then all of a sudden it drops out and stronger stations are in the noise then back again. More often than not the receiver is deaf! I had problems with this last week after I soldered coax to R43 and C32 and it turned out R43 went bad. I replaced it and all has been fine since. Then this morning it  started again, although this time R43 is fine. But I have just noticed I have continuity over a lot of resistors in that area of the board including over both ends on r43?? If I have a short somewhere where do I start?? Would it even power up and work at all if this was the case? 

Help would be much appresciated! 

Carl.

Re: Known issues on uBITX r4 #ubitx

Ralph Mowery
 


I don't know anything about those.  They do say for using with LED strips only.

Most likely they are not regulated and will put out over 12 volts with a light load. 

Another thing is they are probably not very well filtered if any and you may get a lot of hum on your signal.

If they would be regulated and filtered, the 12 volt and 3 amp supply would be the one, but I don't think I would use any of those.

73 de ku4pt


On Fri, Jun 29, 2018 at 1:33 PM, hirosmb JAZZ <hirosmb@...> wrote:
IC.


Is the one like above OK?

Thanks in advance, Ralph.

// hiro, JJ1FXF

Re: RF power chain mods and improvements..

Jer Tres
 

Re predriver (Q911, Q912):

”The 5109 was best even though I used only 1”

So, the question is:
If I use a 2N5109 for the predriver “Should I also change some resistors to adjust the bias? Or should it work without doing so?” and do I need to change any of the caps?

JackAl board pricing

Jack, W8TEE
 

Not yet. We are getting bids on the complete assembly of the PCB, so that all the SMD's are in place. We do know that the Teensy 3.6 is $30 and their audio board which piggybacks on the Teensy and we use for DSP is $14 and the 5" touch screen is a little under $35 (7" is about $45). Our best guess is that the board will be sold for $40-$50. So the bad news is that our addon is almost as much as the µBITX. However, when you're done, you'll have a pretty impressive xcvr. Also, we have some interesting plans for Rev 2.0 software, too, so it will be an ongoing project. BTW, the audio library is a treasure trove of functionality, including a worthwhile FFT library. Finally, we've added a small knot of extra I/O pins which coupled with 1MB of flash and 256K of SRAM should make it a hacker's dream. Despite all that we've done, we're still using less than 20% of the flash and only 12% of the SRAM. Al and I are expecting great things from you people down the road!!

Jack, W8TEE

On Friday, June 29, 2018, 2:38:15 PM EDT, Dennis Yancey <bigbluedry@...> wrote:


Have any pricing done on them yet?

Re: Known issues on uBITX r4 #ubitx

Daniel Conklin
 

If you don' want to deal with RFI problems from the power supply, then get a good analog  supply like the Pyramid PS12KX.  I have a couple of switching supplies that were made for use with communications devices, but they both interfere somewhere on the spectrum.  I've never had a problem with analog power supplies.
Dan, W2DLC

Re: Known issues on uBITX r4 #ubitx

Daniel Conklin
 

The other thing you can do if you don't have a 5A or better supply is turn back the drive to your finals.
Dan, W2DLC

Re: Ubitx receive intermittent

Daniel Conklin
 

Intermittent issues are hard to diagnose because they never show up when the technician is looking for them.  You have to force the issue.  As you check for continuity, you wiggle and flex the PCB and other suspect things until the problem rears its ugly head.
Dan, W2DLC

Re: Known issues on uBITX r4 #ubitx

iz oos
 

I confirm my 2A was not enough and shut down. Use at least a real 3A, linear is better to avoid any issue you might not even a clue.


Il 29/giu/2018 22:48, "Daniel Conklin" <danconklin2@...> ha scritto:
The other thing you can do if you don't have a 5A or better supply is turn back the drive to your finals.
Dan, W2DLC

Re: Known issues on uBITX r4 #ubitx

Bo Barry <bobarr@...>
 

I have a v3 & v4 and am "tickled to death" (American slang expression) with both of them.
NO mods (except KD8CEC mods to one) so far except for a tiny 5v fan.
As a retired engineer having done design, programming, & construction, I continually think about the excellent efforts that went into bringing this unique hardware and software to the market for "pennies'" or free.
I reserve any comments that may be considered criticism by the creators.
I'm sure they appreciate constructive comments about improvements to consider when they have time from their schedules.
So much more fun than the Heathkit days!
73, Bo W4GHV since '54   (at 78, just glad to be alive!)

Re: Known issues on uBITX r4 #ubitx

Bill Cromwell
 

Hi,

I'm using batteries..even with some of my vacuum tube gear. What noise?

73,

Bill KU8H

On 06/29/2018 04:46 PM, Daniel Conklin wrote:
If you don' want to deal with RFI problems from the power supply, then
get a good analog supply like the Pyramid PS12KX. I have a couple of
switching supplies that were made for use with communications devices,
but they both interfere somewhere on the spectrum. I've never had a
problem with analog power supplies.
Dan, W2DLC
--
bark less - wag more

Re: RF power chain mods and improvements..

ajparent1/KB1GMX <kb1gmx@...>
 

adjust resistor if needed for not more than 30mA emitter current.
DId you parallel the emitter resistors too?

FYI it should work as IS but my 5109s wanted to sit there at 70ma and get very warm
That is way to high even 20mA (each) is more than enough.

That problem appeared even with the  original 2n3904s in the predriver and driver
they were very high current and quite hot.

Allison

Re: Shipping issues

bigdswitzer
 

Hal
I ordered mine (6/21) and this morning (6/29) received notice it departed on DHL, estimated delivery (7/6)

David
KG7WFM

Re: RF power chain mods and improvements..

Jer Tres
 

“DId you parallel the emitter resistors too?“
A: R87&R88? No, I was not going to, have not done anything yet but order the 2N5109.

“my 5109s wanted to sit there at 70ma and get very warm
That is way to high even 20mA (each) is more than enough.”
Q: for the predriver I was only going to use one, will 20 to 30 ma emitter current be good if only using one? (For the driver I ordered metal 2N2222A’s)

thanks

Re: Noise Burst #bitx40

Allard PE1NWL
 

Thanks John,
glad to hear you like the software.

73 Allard PE1NWL

On Fri, June 29, 2018 06:21, jah12@... wrote:
Installed raduino v1.27.1 and it works fine. No RF noise burst on
transmit. Great piece of software Allard. 
Now looking to do more hacks of the hardware to take full advantage of the
software features.
73
--
John VK6JAH

Re: KD8CEC Firmware

Glenn
 

ian or anybody, I am trying to locate the actual source of Ian's files for the NEXTION displays to download.

I have looked over Ian's web pages but just cannot find  a link to the files. Any ideas?

glenn
vk3pe

Re: uBitxr4 audio distortion fix

Tim Gorman
 

Three diodes won't fix the problem that the bias on the base of Q73 is
highly dependent on Q71 collector voltage.

If you ever redesign this circuit I would use capacitor coupling from
the collector of Q71 to the bases of Q72 and Q73. The base bias
of Q73 would then be set with a resistor to ground. Then everything is
symmetric and distortion should be minimized.

tim ab0wr



On Fri, 29 Jun 2018 15:45:51 +0530
"Ashhar Farhan" <farhanbox@...> wrote:

What if we use three diodes instead?

On Fri, 29 Jun 2018, 13:35 Raj vu2zap, <@Raj>
wrote:

Got back to town and plugged in the uBitxr4 and found the audio
distorted.

Poking around the finals I found that the two diodes D15 and D16
gave only a drop of 1.2V total
but the final transistors needed more like 1.5V. i.e. 0.75v each.

I simply cut the track between D5 and D16 and soldered a 100 ohms
multiturn preset as shown
in picture below. (Preset leads used is center and one side)

Start with the two soldered connections of the preset set to ZERO
ohms.

Power on and tune to a station at low volume and slowly increase the
preset till the audio
becomes clear. In my board the RX power consumption increased by
25mA at the best sound.
Just check and see that the output transistors are not getting hot.

My board sounded great with 47 Ohms between D15 D16 and I run at
13.6V. If you run at the
same supply voltage then you can try a fixed resistor. For 12V
supply you could try a higher value
like 56/62 or even 68 Ohms.

Cheers

--
Raj, vu2zap
Bengaluru, South India.

[image: Emacs!]


Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

Good morning, Bill and all.

Thanks for your words.

Well, I could sleep well. :)

This is my first time to build up a transceiver in my life.

uBITX really gives me a exciting opportunity that I haven’t had in my life.

OK, time to go to AKIHABARA.

Have a good day, Bill.

// hiro, JJ1FXF


2018/06/30 3:46、Bill Cromwell <wrcromwell@...>のメール:

Hello Hiro,

I understand about the excitement. I had a dreadful time resisting the urge to power mine up on a sheet of cardboard (for insulation) before I formed the case to fit. I did connect power just to confirm whigh way the display had to be mounted :) Murpy's Law you know.

At my shack 'temporary' measures have a habit of becoming more permanent:)

73,

Bill KU8H

On 06/29/2018 12:28 PM, hirosmb JAZZ wrote:
Yes, Bill.

As far as I know, the distortion issue comes up with only v4 ubitx, however it’s just a matter of degree.

I already placed my order with DHL, while taking a train back home today! :)

I also plan to use CEC firmware which I already modified a bit to limit the frequencies to TX in accordance with Japanese regulation.

I compiled the modified firmware which successfully runs on my Arduino UNO now.

Also I ordered a Nextion LCD at eBay which presents really lovely UI/UX.

I don’t think I can sleep properly tonite coz I’m so much excited. :)

Thank you, all of you here who share all the information of ubitx, such a wonderful rig!

// hiro, JJ1FXF



2018/06/30 0:21、Bill Cromwell <wrcromwell@...>のメール:

Hi,

I have V3 with a socketed audio chip labeled as Feb 2018. It worked right out of the box - as advertised. I have not had to make *any* mods at all. I do expect to install the CEC software but that is only to get some options I would like to have for CW. I am already using it for CW. I do not have distirtion, I can tune in SSB and AM stations and they are clear. Lucky me?

Wait until you have actually used your radio to decide if you 'need' mods. Most of the mods I see described are optional and only for the owners perefernces - like my plans to install the CEC software. There will be no hardware changes to mine.

73,

Bill KU8H

--
bark less - wag more


Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

Got it, Ralph.

I will try to find a regulated, noise-filtered 12V 3-5A power supply today.

Thanks for your specific advice.

// hiro, JJ1FXF



2018/06/30 4:53、Ralph Mowery <rmowery42@...>のメール:


I don't know anything about those.  They do say for using with LED strips only.

Most likely they are not regulated and will put out over 12 volts with a light load. 

Another thing is they are probably not very well filtered if any and you may get a lot of hum on your signal.

If they would be regulated and filtered, the 12 volt and 3 amp supply would be the one, but I don't think I would use any of those.

73 de ku4pt


On Fri, Jun 29, 2018 at 1:33 PM, hirosmb JAZZ <hirosmb@...> wrote:
IC.


Is the one like above OK?

Thanks in advance, Ralph.

// hiro, JJ1FXF