Date   

Re: Harmonics

F1BFU - Fr - 79
 

Hello Glenn

Here is the photo with the QRPLabs relay card at the real-world level.

Gilles F1BFU / FR
IMAG0379.jpg


Le dim. 12 août 2018 à 11:46, Glenn <glennp@...> a écrit :
Gordon, hope I have the intent on your PCB correct. If not ignore me.......

What about making the PCB so it stands vertically against the edge of the uBITX main pcb, adjacent to the LPF section. The new relays will end up above the uBITX board.  

Cut the existing tracks as per Allisons information.

Scrape the resist off under the uBITX board in the area of the LPF and about 2-3mm wide. ie GND plane.

Your new board can then but upto the uBITX board and be seam soldered to the uBITX underneath.

Very short (5mm) wire link from the end of each LPF to your board.

Glenn vk3pe


Re: Harmonics

ajparent1/KB1GMX <kb1gmx@...>
 

Glen,

That is pure genius!  For the ubitx too.

Clear the few non DC wires and flip it.  Then clean up the top.

Allison


Re: Proposed fix for Harmonics Issue

Howard Fidel
 

John:
Thanks for your support. I am a true believer in the KISS principle. I have spent my professional engineering career putting out "fires" with simple elegant solutions and designing new products. Now in my "retirement" years (actually I still work part time, teaching) I have time to get back to a hobby I started in junior  high school that launched my career in medical electronics. It has been a lot of fun working on the uBitx, and it has exposed me to many engineering issues that I didn't face in the medical area. My plan from the beginning is to use it as a learning experience to launch my next project which will be a SDR transceiver. These harmonics and spur issues have been a distraction but also a great learning experience. It is great to see so many of us working on solutions.

Howard


On 8/12/2018 9:02 AM, John KC9OJV wrote:
Howard,

Your solution seems to be the "holy grail" elegant fix for this problem. Even if the board layout impedes the success of this idea it points to a version 5 modification that could be easily implemented in India. On another note, I don't have a lab grade spectrum analyzer but I do have a RF Explorer analyzer and I loosely coupled it yesterday looking at 40 and 20 meters. The harmonics were present and objectionable. I installed a contester's 6 band switchable bandpass system and the harmonics were sufficiently suppressed. Apparently external filtering is an effective interim solution. Thanks so much for the good thinking on this vexing trouble!

John
KC9OJV



Re: LM386 Innards

Jerry Gaffke
 

Looks like an excellent analysis.
Especially the computations regarding frequency response.
Thanks!
 


On Sun, Aug 12, 2018 at 07:31 AM, Mark McNabb wrote:
Here's a nice reference you may have missed:

https://www.electrosmash.com/lm386-analysis


Re: Need Help

ajparent1/KB1GMX <kb1gmx@...>
 

The V4 schematic is at hf signals as well.

Allison


Re: Need Help

bdunk@...
 

Good morning Allison,

After seeing Larry N2AJX's post and reading yours from August 6th I went out and bought a Arduino original Nano and used jumper wires to connect it.
Every thing is now working!
A Big thanks to all helped with this.
Allison ajparent1/KB1GMX
Jack Prudum
Karl Heinz
Tom KB6B
James Lynes

The board I have is a ubitx v4 any idea were I can find a schematic for it?

All the best to everyone,

Albert VE3TYX


Re: Three cheers for the uBITX! Keeping problems in perspective....

Roy Appleton
 

Thank God, because at times it sure doesn't seem that way!

Roy
WA0YMH

On Sun, Aug 12, 2018, 9:42 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
That is the case.

The uBitx has teething issues. Is a kindness and a truth.
Any of the noted issues are fixable or there are workarounds.

As a builders project radio, its a goldmine.
For those that wish to play with arduino in a radio setting its
happyland.

One should not conflate hardcore conversations on technical issues
around the found problems with negativity.  For some of us solving
those problems is grist for our mills and our strange idea of a fun
challenge.

Allison


Re: BITX QSO Afternoon/Evening, Sunday, August 12, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Gwen Patton <ardrhi@...>
 

EEP. I had that happen earlier in the year. An ice storm came through with a bunch of snow and ripped a huge pine tree in our front yard out of the ground and delicately laid it across the power and comm cables along the roadside. It knocked out power to the neighborhood, and took me a day and a half to get removed so the power company could restore the power. Surprisingly enough, my antenna survived. THAT was anchored to an oak tree on the other side of the yard.

Yesterday's storm didn't do us any damage, but scared the snot out of me. I was driving a ground rod at the edge of our front porch and had just started attaching the ground wire to it when the thunderboomer slammed in, blowing rain sideways so it drenched me. I was afraid that, since I was holding a grounded line, I was probably going to become a protein-based fuse if I didn't drop the wire and get inside. Probably wise of me.


Re: Three cheers for the uBITX! Keeping problems in perspective....

ajparent1/KB1GMX <kb1gmx@...>
 

That is the case.

The uBitx has teething issues. Is a kindness and a truth.
Any of the noted issues are fixable or there are workarounds.

As a builders project radio, its a goldmine.
For those that wish to play with arduino in a radio setting its
happyland.

One should not conflate hardcore conversations on technical issues
around the found problems with negativity.  For some of us solving
those problems is grist for our mills and our strange idea of a fun
challenge.

Allison


Re: LM386 Innards

 

Hi Jerry,

Here's a nice reference you may have missed:

https://www.electrosmash.com/lm386-analysis

Cheers,


Mark.


Re: BITX QSO Afternoon/Evening, Sunday, August 12, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Konrad Kristensen <konrad.kristensen@...>
 

Jack,
Sorry, - very sorry, to read the bad news.

The winds were strong up here, but you must really have been hit hard.

Konrad,

On Sun, Aug 12, 2018 at 10:08 AM Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
Storm late yesterday afternoon with 80mph straight-line winds. Limbs, indeed, entire trees, down or uprooted. I think my antenna is somewhere in WV.

Jack, W8TEE

On Sunday, August 12, 2018, 9:50:54 AM EDT, John P <j.m.price@...> wrote:


Just a reminder!
--
John - WA2FZW


Re: Spurs - BPF fix? #ubitx

Arv Evans
 

Glen

I really like the pictorial representation.  Thanks for that.

Arv
_._


On Sun, Aug 12, 2018 at 3:28 AM Glenn <glennp@...> wrote:
Allison, yes we are on same page. See summary in picture below. Hopefully correct and less my typos in previous post.

The 15M band is odd one out though for switching.

Yes, i know anything  is possible.   But there are at least 3 or 4 variations on the uBITX Sketch so an agreement has to come on how to do this and also make it not so difficult that people can't be bothered to make the changes. Of course in the end, we can't push people to do this if they don't want to, but we do have to make it as easy as possible in my view. There have been hundreds on this and similar topic, but it's like a Committee where nothing changes so far.


Re: BITX QSO Afternoon/Evening, Sunday, August 12, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Jack, W8TEE
 

Storm late yesterday afternoon with 80mph straight-line winds. Limbs, indeed, entire trees, down or uprooted. I think my antenna is somewhere in WV.

Jack, W8TEE

On Sunday, August 12, 2018, 9:50:54 AM EDT, John P <j.m.price@...> wrote:


Just a reminder!
--
John - WA2FZW


Re: BITX QSO Afternoon/Evening, Sunday, August 12, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

John P
 

Just a reminder!
--
John - WA2FZW


Re: Spurs - BPF fix? #ubitx

ajparent1/KB1GMX <kb1gmx@...>
 

Glen,

Had to kill off a double post.

Your graphic is good.  However the assumption is for the HPF is that 
there is a 33mhz LPF (the existing one). 

Also things like the 27mhz spur only happen when operating on 17M
The main spurs are always be 45mhz - current TX frequency for
SSB only.  (W we only have to deal with harmonics.).

What you refer to as compact LPF is just the same as the output LPF or similar.
Its cutoff is about 19-20mhz so it works for 20 and 17M as their second
harmonics and spurs are well over 20mhz.

I'd need to so some testing (not this week) and you should as well on
the behavior of cascaded filters without isolation.  In the past I've had
situations of higher losses and odd peaks and dips. They don't always
go back to back.  If the assumption is the 9elemment filter is RX only
thats ok bt for TX that means here there is only HPF all the stuff to
over 100mhz makes it to the amp and adds to the IMD.

If its possible to make it fit the current sketch wonderful. In general the
code to do it is similar if not identical save for pin numbers for some
of the more exotic (tensey, bluepill..) hardware.  For Arduino the
code in its many flavors are branches of the same trunk.

Allison


Re: Three cheers for the uBITX! Keeping problems in perspective....

Yeonghwan Jun
 

We occasionally confuse uBITX with conventional commercial radios.
However, many are working to improve this somewhat impaired product.
This is consistent with the value that amateur radio pursues.
uBITX gives us the pleasure of communication and the pleasure of improvement through small cost.

Anyway, thanks to Mr. Farhan and thank you.


Re: Proposed fix for Harmonics Issue

John KC9OJV
 

Howard,

Your solution seems to be the "holy grail" elegant fix for this problem. Even if the board layout impedes the success of this idea it points to a version 5 modification that could be easily implemented in India. On another note, I don't have a lab grade spectrum analyzer but I do have a RF Explorer analyzer and I loosely coupled it yesterday looking at 40 and 20 meters. The harmonics were present and objectionable. I installed a contester's 6 band switchable bandpass system and the harmonics were sufficiently suppressed. Apparently external filtering is an effective interim solution. Thanks so much for the good thinking on this vexing trouble!

John
KC9OJV


Re: Bitx40 spot function

Ken
 

Thanks Marco for pointing this out.

73 Ken

On Sat, Aug 11, 2018 at 10:05 AM, M Garza <mgarza896@...> wrote:
Hi Ken,
Please look at Allard's firmware.  
It provides many features with just a few mods to the hardware.  SPOT is one of the features, I believe.

73s

Marco - KG5PRT 

On Sat, Aug 11, 2018, 8:55 AM Ken <chase8043@...> wrote:
Hi All

Quite a while ago there was discussion on unbalancing DBM for a spot function. I'd like this on a stock Bitx40.

73

Ken VA3ABN



Re: Three cheers for the uBITX! Keeping problems in perspective....

Don - KM4UDX
 

I thought I died and went to heaven when my uBITX came in the mail. How often do you get to feel 14 years old again at the ripe age of 62? Warming up the solder iron, organizing the parts, and reading (a hundred times) the instructions trying to understand what is meant vs what is said.

There is a current expression...now we get to pimp our ride.

Historically we customized our hotrod. Or in my case a very used plymouth with new speakers. hahahah.

What joy, what bliss to be back there again. 

So I can only say thank you a thousand times to the Great Dr. for his creation, and for all of you who helped with community development, support and encouragement. 

Don
km4udx


Re: Harmonics

Gordon Gibby <ggibby@...>
 

Hi folks....


Well 1-3/4 hours into this, and I haven't gotten near as much as I hoped to get done, and time to go get dressed for early church......


When I started working on the "cuts" to be made, using Allison's excellent photo, I realized for the first time that for 3 out of the four low pass output filters, the "input" to the filter is on the outside of the board.   One filter, the 400 nH-inductor filter, is the opposite; the "input" side of that one is on the inside of the board and the output is on the outside.....


That complicates things because, in general, we would prefer to have people make their connections  to the side of the filters nearest the edge of the board (and also avoid looooonnng traces retracing the filter physical length) --- so for 3 out of the 4 filters, the side we prefer to connect to is the INPUT to the filters..... 



Hence it might be better for my added additional filters to switch the INPUT to the filters, and leave the majority of the on-board filters doing the antenna-end of the schematic.   



That threw me for a loop and I had to start all over with the schematic, carefully comparing to the physical layout and picking where I wanted the cuts.....so I have a first cut at a new "adjusted" original V3 V4 ubitx schematic, but not confident enough to release it just now.   However, I think I've identified the wires to cut to flip my plans and the wires to bring out to the external board (which as Glenn points out, could potentially be mounted at right angles and take up very little additional space).    



So later today I hope to get back to this and create


a)  Schematic of original uBitx showing which schematic wires will be cut  and those to be brought out (I have a rough of that)

b)  Adjusted photo from Allison's photo showing physically which ones to cut.   Because ONE filter is physically different, that one filter will need a bit more care.   It is the 400 nH filter.

c)  Schematic of external relay setup switching the INPUTS to the filters

d)  Board layout of the external relay setup, leading to Gerber files.....    


Now I understand even more why Allison didn't like the wiring underneath the relays on the top of the board.   More power to all the people who have worked so hard on all this.     Multiple solutions being undertaken by several bright people.    


Gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Sunday, August 12, 2018 5:50:24 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonics
 
Glenn, I agree completely.   I’m going to try to finish the printed circuit board layout today.

I’m going to see if I can move the inputs a little further towards the edge which would make this easier to do.   


Thank you for your great idea!  It had somewhat occurred to me but your photo is very convincing.






On Aug 12, 2018, at 05:46, Glenn <glennp@...> wrote:

Gordon, hope I have the intent on your PCB correct. If not ignore me.......

What about making the PCB so it stands vertically against the edge of the uBITX main pcb, adjacent to the LPF section. The new relays will end up above the uBITX board.  

Cut the existing tracks as per Allisons information.

Scrape the resist off under the uBITX board in the area of the LPF and about 2-3mm wide. ie GND plane.

Your new board can then but upto the uBITX board and be seam soldered to the uBITX underneath.

Very short (5mm) wire link from the end of each LPF to your board.

Glenn vk3pe

<LPF_POSSIBLE_PCB.JPG>