Date   
Re: VK4PP uBitx LPF BANK add-on Board

Gordon Gibby <ggibby@...>
 

....was  supposed to read  "a low pass filter above 20 METERS"  (not MHz)

cheers,  gotta go cut some grass before it pours again....


gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Friday, August 31, 2018 2:41 PM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 

Warren, you are right on, but you might not have seen all the posts where I did exactly what you are saying.   Both BEFORE the daughterboard and AFTER the daughterboard so i had proof of its effectiveness.   I also did some calibrations of the S-meter using BNC attenuators (which is all I have).   I then did the suggested measurements of today, measuring bleed-through (unmeasureable, whereas I was clearly able to measure the harmonics and able to measure their reduction by moving the input side of the relay chain OFF the board.)


Here, I'll see if I can find the posts (I'm not too used to that):


(1)Very first "before" measurements:   https://groups.io/g/BITX20/message/57840

(2)Complete baseline data:   https://groups.io/g/BITX20/message/57974

(3) Calibration of the S-meter and proof that the measurement setup itself didn't have bleed thru:  https://groups.io/g/BITX20/message/58070

  [This distinctly showed that 1 S unit in the range of 7-9 is 12 db onthat receiver on that frequency)

(4)Photos of the measurement setup:  https://groups.io/g/BITX20/message/58070

(5) DAta AFTER daughterboard:   https://groups.io/g/BITX20/message/58070



What I CANNOT prove is that the receiver maintains identifical response at all frequencies (hence, is "flat")  however it is reasonable that the differnces aren't mroe than a few dB based on specifications for rigs of this price range etc.   


Poor man's spectrum analyzer.   What is problematic is the 24MHz harmonic range --- here I achieved only 6 dB reduction so there is something else going on there...maybe a series resonance in a filter or somethign I haven't thought of.   Every other range was dramatically reduced by the daughterboard system.   So for my purposes --- a low pass filter above 20 MHz and I have every digital band I need for what I need out of the radio and I don't need to use the bands where the "spurs" are a thorn.   



Hope that makes more sense.   

Cheers,


gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Warren Allgyer <allgyer@...>
Sent: Friday, August 31, 2018 2:24 PM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 
Gordon

Your reasoning makes perfect sense. But I think you can measure at the actual harmonic frequencies which is where the issue would be . Your IC-718 can tune the third, fifth and 7th harmonics of 80 meters. So you can know exactly (within the limits of the S meter calibration and linearity) what the residual level is at the harmonic frequencies themselves. You have checked your S-meter and you know what represents 45-50 dB below S9+30 (normally one S unit = 6 dB but in real life S meters rarely replicate that). So just tune the harmonics directly and measure them. Or am I missing something?

WA8TOD

Re: VK4PP uBitx LPF BANK add-on Board

Gordon Gibby <ggibby@...>
 

Warren, you are right on, but you might not have seen all the posts where I did exactly what you are saying.   Both BEFORE the daughterboard and AFTER the daughterboard so i had proof of its effectiveness.   I also did some calibrations of the S-meter using BNC attenuators (which is all I have).   I then did the suggested measurements of today, measuring bleed-through (unmeasureable, whereas I was clearly able to measure the harmonics and able to measure their reduction by moving the input side of the relay chain OFF the board.)


Here, I'll see if I can find the posts (I'm not too used to that):


(1)Very first "before" measurements:   https://groups.io/g/BITX20/message/57840

(2)Complete baseline data:   https://groups.io/g/BITX20/message/57974

(3) Calibration of the S-meter and proof that the measurement setup itself didn't have bleed thru:  https://groups.io/g/BITX20/message/58070

  [This distinctly showed that 1 S unit in the range of 7-9 is 12 db onthat receiver on that frequency)

(4)Photos of the measurement setup:  https://groups.io/g/BITX20/message/58070

(5) DAta AFTER daughterboard:   https://groups.io/g/BITX20/message/58070



What I CANNOT prove is that the receiver maintains identifical response at all frequencies (hence, is "flat")  however it is reasonable that the differnces aren't mroe than a few dB based on specifications for rigs of this price range etc.   


Poor man's spectrum analyzer.   What is problematic is the 24MHz harmonic range --- here I achieved only 6 dB reduction so there is something else going on there...maybe a series resonance in a filter or somethign I haven't thought of.   Every other range was dramatically reduced by the daughterboard system.   So for my purposes --- a low pass filter above 20 MHz and I have every digital band I need for what I need out of the radio and I don't need to use the bands where the "spurs" are a thorn.   



Hope that makes more sense.   

Cheers,


gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Warren Allgyer <allgyer@...>
Sent: Friday, August 31, 2018 2:24 PM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 
Gordon

Your reasoning makes perfect sense. But I think you can measure at the actual harmonic frequencies which is where the issue would be . Your IC-718 can tune the third, fifth and 7th harmonics of 80 meters. So you can know exactly (within the limits of the S meter calibration and linearity) what the residual level is at the harmonic frequencies themselves. You have checked your S-meter and you know what represents 45-50 dB below S9+30 (normally one S unit = 6 dB but in real life S meters rarely replicate that). So just tune the harmonics directly and measure them. Or am I missing something?

WA8TOD

Re: BITX40 Saving Settings Issue

Allard PE1NWL
 

Hi Gary,

it could also be a timing issue.

At line 2327, there is a short 100ms delay:

delay(100);               // allow the voltages on the Arduino inputs to
settle for some milliseconds after power on

Perhaps the 100ms is just not enough for your radio.
You could try 200ms and see if it helps.
Simply change
delay(100);
to
delay(200);
Then recompile and upload to the Raduino. Please let me know if this helps. 73 Allard PE1NWL

KARMA and BITX

Lawrence Macionski <am_fm_radio@...>
 

Is  this Karma?

Howard E. Michel, WB2ITX, is New ARRL Chief Executive Officer

The ARRL Board of Directors has elected Howard E. Michel, WB2ITX, of Dartmouth, Massachusetts, to be ARRL's new Chief Executive Officer. He will start on October 15. Michel (rhymes with "nickel") is currently Chief Technology Officer at UBTECH Education, and Senior Vice President of UBTECH Robotics, a $5 billion Shenzhen, China, artificial intelligence and robotics company. As the Chief Technology Officer at UBTECH Education, Michel helped build this company from a startup in China to $100 million in valuation.
Full Story......
http://www.arrl.org/arrlletter?issue=2018-08-31

NNNN
Larry W8LM
ARRL Life Member

Re: VK4PP uBitx LPF BANK add-on Board

Warren Allgyer <allgyer@...>
 

Gordon

Your reasoning makes perfect sense. But I think you can measure at the actual harmonic frequencies which is where the issue would be . Your IC-718 can tune the third, fifth and 7th harmonics of 80 meters. So you can know exactly (within the limits of the S meter calibration and linearity) what the residual level is at the harmonic frequencies themselves. You have checked your S-meter and you know what represents 45-50 dB below S9+30 (normally one S unit = 6 dB but in real life S meters rarely replicate that). So just tune the harmonics directly and measure them. Or am I missing something?

WA8TOD

Re: VK4PP uBitx LPF BANK add-on Board

Gordon Gibby <ggibby@...>
 

Hi, I get that.   I but Icannot measure it at all frequencies.  I don't have a spectrum analyzer, I have a RECEIVER and I've calibrated portions of its response in order to use it as a poor-mans spectrum analyzer.    Presumably the blow-by is capacitive for the most part, but not at all parts.   Lacking a spectrum analyzer, I measure the effective blow by at ONE frequency and then draw assumptions at others based on a model that it is primarily capacitve in nature (which has been the major point of discussion for weeks now......)


So if you know that capacitive reactance goes down by 10X when you increase the frequency by 10X, and in both cases you are feeding into a 50 ohm load.......the voltage you're going to get will go up on the order of 10X.    


​Thus you can make a prediction (based on the model) of what the bleed through might be at higher frequencies.   Or you can risk your rig by making other measurements if you don't have any other way to do it (which is me).   Does that make more sense?


Cheers,


gordo



From: BITX20@groups.io <BITX20@groups.io> on behalf of Warren Allgyer <allgyer@...>
Sent: Friday, August 31, 2018 1:50 PM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 

Gordon

"Bleed through" or "blow by" at the operating frequency is not the issue. It is bleed through at the 5th and 7th harmonic that allows those harmonics to reach levels that are non-compliant.

WA8TOD

Re: 4.2" Nextion Bezel? #3d_printing #ubitx-help

Bill Cromwell
 

Hi,

I made the bezel for my stock display from a nice piece of scrap wood. You could do the same for your bigger display.

73,

Bill KU8H

On 08/31/2018 11:31 AM, David Posthuma wrote:
I am using the 4.2" Nextion touch screen on my Ubitx. Does anyone know
where I can get a small black bezel/frame for it? I only need about
1/4-inch on all sides. Unfortunately, I don't have access to a 3D
printer. Thank you for any leads the group may provide.
--
bark less - wag more

Re: VK4PP uBitx LPF BANK add-on Board

Warren Allgyer <allgyer@...>
 

Gordon

"Bleed through" or "blow by" at the operating frequency is not the issue. It is bleed through at the 5th and 7th harmonic that allows those harmonics to reach levels that are non-compliant.

WA8TOD

Re: UBITX V3 TX GAIN VARIATIONS

Kees T
 

On Thu, Aug 30, 2018 at 09:42 PM, ajparent1/KB1GMX wrote:
The cap does not need to be a 500V part even at 28V as the mosfets will self destruct
at 100V, so a 100V cap is fine so long as it can handle high RF current.
I've found that the 500V caps are more "robust" from a current handling and stability standpoint...and those are 500V DCWV. At RF (AC) they are all derated. I use a "rule of thumb" (which is easy for me to remember) ....50%.  That also means you have to consider the RF voltage rating of the blocking capacitors in the feedback loops. If they fail the associated MOSFET is toast.

73 Kees K5BCQ 

Re: ATU for mBITX

Lawrence Galea
 

Google picatune ATU

On Fri, Aug 31, 2018 at 5:46 PM n5ib_2 <n5ib@...> wrote:
The bias tee isn't used to power the T1, since it has internal battery power, and, with latching relays, only draws power when tuning.
The bias tee, using a lithium coin cell for DC power, fires an optical isolator at the antenna end that triggers the remote control line on the T1.

So the only connection between the Tx and the T1 is the coax.

N5IB







Re: VK4PP uBitx LPF BANK add-on Board

Gordon Gibby <ggibby@...>
 

The measurements that I made  for the daughterboard  bleed-through indicate that for the ENTIRE SYSTEM,  including the printed circuit board, connecting leads, relays, coils, coil wiring and all the RF wiring,  the bleed  through is almost NEGLIGIBLE. (lifted the bottom green wire in the accompanying photo and measured bleed through that had to go through ALL SIX RELAYS).    Far, far below the pass through the filter....  down to unmeasureable on the ICOM718..whereas properly filtered harmonics  were depressed into the S5 or S6 range from 30dB overS9  fundamental (as predicted by others' measurements indicating the FILTERS had acceptable performance)     Measurement performed at 3.5  MHz.  Presumably capacitive coupling would increase related to frequency, perhaps 10 times the amount would be expected at 30 MHz --- but that would only be 10dB more signal, perhaps reaching to S2   I don't want to risk my finals by doing  the experiment over and over.   The bleed through with a daughterboard --- even with unshielded wires --- is far far far below  the requirements to meet FCC specs.    (-43 dB being  somewhere around S7.5 in my tests).    Get the relays separated, get the things apart physically that need to NOT bleed into each other....and it isn't that difficult to fix the harmonics.  (The spurs are a different issue).   





From: BITX20@groups.io <BITX20@groups.io> on behalf of Jerry Gaffke via Groups.Io <jgaffke@...>
Sent: Friday, August 31, 2018 12:17 PM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 
I interpret this measurement from Glenn:
    "-32dB from one set of contacts to the other. (common terminal)"
as being from KT1 pin 14 to pin 16 as seen in the uBitx schematic.

Also, interpret his -39 and -41 dB numbers to be from one relay section to the other,
which I averaged as -40dB.    For example, KT1 pin 12 to pin 5.

I now suspect those assumptions are incorrect, but the analysis could easily be adjusted to for any change to those two numbers.

Jerry


On Fri, Aug 31, 2018 at 03:40 AM, Glenn wrote:
All good points Warren.   I did some checks of isolation using a typical DIP relay, type HK19F. DPDT

I made a small jig to hold the relays and measure isolation across contacts etc.
Typically it was -34dB across open contacts,
-32dB from one set of contacts to the other. (common terminal)
-41dB from open terminals on each side
-39dB from common of one pole to open on the other pole.
-48db from common to coil.
 At 30MHz.  Better as freq drops of course.
That's without effects of a PCB and various other traces.

glenn

Re: VK4PP uBitx LPF BANK add-on Board

Jerry Gaffke
 

I interpret this measurement from Glenn:
    "-32dB from one set of contacts to the other. (common terminal)"
as being from KT1 pin 14 to pin 16 as seen in the uBitx schematic.

Also, interpret his -39 and -41 dB numbers to be from one relay section to the other,
which I averaged as -40dB.    For example, KT1 pin 12 to pin 5.

I now suspect those assumptions are incorrect, but the analysis could easily be adjusted to for any change to those two numbers.

Jerry


On Fri, Aug 31, 2018 at 03:40 AM, Glenn wrote:
All good points Warren.   I did some checks of isolation using a typical DIP relay, type HK19F. DPDT

I made a small jig to hold the relays and measure isolation across contacts etc.
Typically it was -34dB across open contacts,
-32dB from one set of contacts to the other. (common terminal)
-41dB from open terminals on each side
-39dB from common of one pole to open on the other pole.
-48db from common to coil.
 At 30MHz.  Better as freq drops of course.
That's without effects of a PCB and various other traces.

glenn

Re: VK4PP uBitx LPF BANK add-on Board

Jerry Gaffke
 

In many places, I said "30m" when I should have said 10m (or 30mhz) in that previous post.
Here's an edited version:



The relays are not that bad, primary issue on the uBitx is how the board is routed. 

Look at the uBitx schematic, find KT1 near the 10m (10 meters, or 30mhz) LPF of L11,12,13.
Assume the relays are in the relaxed state as drawn, for operation at 10m.

The 32dB number is for isolation from KT1 pin 14 to 16.
So when operating at 10m, we have 32dB of loss going from pin 14 to pin 16, 
through the 20m filter at L14,15,16, and then another 32dB of loss
going from KT1 pin 1 to 3 at the other side of the filters.  A total of 64dB down
to sneak around the KT1 filter by that path.  The third filter is not a factor for this
since it is an additional 64dB down.  

The roughly 40dB loss in going around the 10m LPF from KT1 pin 12 to 5
is the primary factor that the relays themselves contribute to blow-by,
that's acceptable unless the PA is putting out harmonics that are as strong as the fundamental.
That 40dB path disappears if we use 3 additional relays at the far side of the LPF's.
 
Blow-by when operating on 10m is the primary consideration,
operating at lower frequencies will have proportionally less capacitive coupling through the relays.



Someone proposed the scheme below a few weeks ago using a total of 4 DPDT relays 
which I have named RA, RB, RC, RD.
I forget exactly who brought this up, it came as a web pointer to schematics for a board in production. 
There's blow-by when operating on 10m of 32+32=64dB through RB, RD, and the 20m LPF.
There is also a path of path across RA, RC, and the 40m LPF of 32+32=64dB.
And a path across the RB and RD relay sections of 40+40=80dB through that same 40m LPF.
With all three blow-by paths of 64,64, and 80 dB in parallel, we have a net of about 57dB of blow-by.
Not bad for just 4 relays, and the board routes sort out nicely.

                    o---------[10m]---------o
               +----o RB                 RD o----+
               |    o---------[20m]---------o    |
               |                                 |
         o-----+                                 +--------o
---------o RA                                          RC o---------
         o-----+                                 +--------o
               |                                 |
               |                                 |

               |    o---------[40m]---------o    |
               +----o RB                 RD o----+
                    o---------[80m]---------o

Jerry, KE7ER
 

Re: 4.2" Nextion Bezel? #3d_printing #ubitx-help

Christopher Miller
 

I could probably help but I don't have any black pla to print with. Here in Tucson we have a maker space called xero craft. You may have one where you live. Xero for example has a couple of printers that can be used for a donation. Another option would be to use shapeway or some other site that will print and mail an object for a fee.

Feel free to contact me if you are willing to pay for a spool of filament and I will be happy to do it.

Chris

On Fri, Aug 31, 2018, 8:31 AM David Posthuma <davep@...> wrote:
I am using the 4.2" Nextion touch screen on my Ubitx. Does anyone know where I can get a small black bezel/frame for it? I only need about 1/4-inch on all sides. Unfortunately, I don't have access to a 3D printer. Thank you for any leads the group may provide.

Re: ATU for mBITX

n5ib_2
 

The bias tee isn't used to power the T1, since it has internal battery power, and, with latching relays, only draws power when tuning.
The bias tee, using a lithium coin cell for DC power, fires an optical isolator at the antenna end that triggers the remote control line on the T1.

So the only connection between the Tx and the T1 is the coax.

N5IB

Re: VK4PP uBitx LPF BANK add-on Board

Gordon Gibby <ggibby@...>
 

I decided to test the  little daughterboard system that I built to move the input filtering off theboard.


Everything connected:  80 metersignal (has to go thru three relays on the board and 3 relays off the board):  S9+30 dB in my apprxoimately 70db attenuation system.


Remove the wire from the soldered-to-the-trace input to just the 80 meter LPF, lay it a couple centimeters to the side....


Signal  dropped to barely hearable and S0.


30 db for  the portion above S9  (verified with attentuators)

18 db more toget to S7.5  (verified  with attentuators)


Unknown from S7.5 to S0 but likely at  least 6db/Sunit (sincethose above7 were 12dB perS unit measured) --42 db


Total isolation at 80 meters roughly 90 dB

​at the very least (down to the verified  S7.5 point) 48 dB + whatever it takes to go from 7.5 to0  

Icom718.


So the isolation at 80 meters seems good....probably declines with frequency 


gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Glenn <glennp@...>
Sent: Friday, August 31, 2018 6:40 AM
To: BITX20@groups.io
Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board
 
All good points Warren.   I did some checks of isolation using a typical DIP relay, type HK19F. DPDT

I made a small jig to hold the relays and measure isolation across contacts etc.
Typically it was -34dB across open contacts,
-32dB from one set of contacts to the other. (common terminal)
-41dB from open terminals on each side
-39dB from common of one pole to open on the other pole.
-48db from common to coil.
 At 30MHz.  Better as freq drops of course.
That's without effects of a PCB and various other traces.

glenn

Re: ATU for mBITX

Jim Sheldon
 

One other thing on the Elecraft T1 autotuner.  I remember something that Wayne Burdick, N6KR (Elecraft founder and CEO) said about the T1.  During initial testing of it, he messed up and accidentally hit it with 100 watts for a brief period (It's spec'd for 20W CW max) and it survived.  Of course, this isn't recommended but it speaks well for Elecraft's product quality.  

I have one I use regularly in portable ops with rigs other than my KX2 and I built 2 from the kits for others who didn't want to attempt the very close soldering necessary to install the relays in it.  

I've had mine for over 5 years now and it runs just fine.  I had forgotten about N5IB's "bias tee" but that's a really good way to power it remotely.  You still have to use a separate remote cable and that must be well shielded, but you wouldn't have to be checking on the battery all the time.  

The T1 should handle a stock 10-20 watt uBITX with no problem and will match some pretty wierd antenna configurations on many bands.

Jim, W0EB

------ Original Message ------
From: "Jim Sheldon" <w0eb@...>
Sent: 8/31/2018 10:11:15 AM
Subject: Re: [BITX20] ATU for mBITX

I've built 3 of them and they remote very easily but you do have to use well shielded cables as any RF pickup tends to mess up the tuning.

Elecraft's software is NOT hackable and is proprietary, not open-source.  

Jim

------ Original Message ------
From: "W2CTX" <w2ctx@...>
Sent: 8/31/2018 10:04:33 AM
Subject: Re: [BITX20] ATU for mBITX

http://www.elecraft.com/manual/E740079%20T1%20owners%20man%20rev%20B.pdf


There is already a jack to remote control it.  See manual.


rOn

On August 31, 2018 at 8:50 AM "Tom, wb6b" <wb6b@...> wrote:

On Thu, Aug 30, 2018 at 09:36 AM, ajparent1/KB1GMX wrote:
T1 its the ideal pocket sized ATU
That's a cool Auto Tuner. Did not realize Elecraft made a reasonable cost Auto ATU. Wonder how hard it would be to hack it, so I could put in in a weather proof box at my antenna and remotely control it?

Tom, wb6b

Re: VK4PP uBitx LPF BANK add-on Board

Jerry Gaffke
 

Warren,

The relays are not that bad, primary issue on the uBitx is how the board is routed. 

Look at the uBitx schematic, find KT1 near the 30m LPF of L11,12,13.
Assume the relays are in the relaxed state as drawn, for operation at 30m.

The 32dB number is for isolation from KT1 pin 14 to 16.
So when operating at 30mhz, we have 32dB of loss going from pin 14 to pin 16, 
through the 20m filter at L14,15,16, and then another 32dB of loss
going from KT1 pin 1 to 3 at the other side of the filters.  A total of 64dB down
to sneak around the KT1 filter by that path.  The third filter is not a factor for this
since it is an additional 64dB down.  

The roughly 40dB loss in going around the 30m LPF from KT1 pin 12 to 5
is the primary factor that the relays themselves contribute to blow-by,
that's acceptable unless the PA is putting out harmonics that are as strong as the fundamental.
That 40dB path disappears if we use 3 additional relays at the far side of the LPF's.
 
Blow-by when operating on 30m is the primary consideration,
operating at lower frequencies will have proportionally less capacitive coupling through the relays.



Someone proposed the scheme below a few weeks ago using a total of 4 DPDT relays
which I have named RA, RB, RC, RD.
I forget exactly who brought this up, it came as a web pointer to schematics for a board in production. 
There's blow-by when operating on 30m of 32+32=64dB through RB, RD, and the 20m LPF.
There is also a path of path across RA, RC, and the 40m LPF of 32+32=64dB.
And a path across the RB and RD relay sections of 40+40=80dB through that same 40m LPF.
With all three blow-by paths of 64,64, and 80 dB in parallel, we have a net of about 57dB of blow-by.
Not bad for just 4 relays, and the board routes sort out nicely.

                    o---------[10m]---------o
               +----o RB                 RD o----+
               |    o---------[20m]---------o    |
               |                                 |
         o-----+                                 +--------o
---------o RA                                          RC o---------
         o-----+                                 +--------o
               |                                 |
               |                                 |

               |    o---------[40m]---------o    |
               +----o RB                 RD o----+
                    o---------[80m]---------o

Jerry, KE7ER
 


On Fri, Aug 31, 2018 at 06:01 AM, Warren Allgyer wrote:
That 32 dB number is the killer for the uBitx relay scheme. It gets at least 3 dB worse with each relay added to the chain and all four relays are in the chain.

4.2" Nextion Bezel? #3d_printing #ubitx-help

 

I am using the 4.2" Nextion touch screen on my Ubitx. Does anyone know where I can get a small black bezel/frame for it? I only need about 1/4-inch on all sides. Unfortunately, I don't have access to a 3D printer. Thank you for any leads the group may provide.

Re: ATU for mBITX

n5ib_2
 

look at the "Bias Tee" link at <http://qsl.net/n5ib/>
for a way to remote the Elecraft T1 and run power on the coax.

Each of the two Bias Tee units will fit the traditional Altoids tin.
The T1 tuner and its Bias Tee can be fitted into a weatherproof box at the antenna
At the Tx end an SWR meter is needed to monitor/verify the match.

N5IB