Date   
Re: BitX40 Sketch still needed....

AA9GG
 

I have that, but was hoping someone has a copy modified for use with a rotary encoder instead of the pot....

Re: Harmonic performance - SSB vs CW

RCBoatGuy
 

Actually, the more I look a the mcHF RF board schmatics, the more i think its a good solution for the BPF, PA, and LPF issues. The mcHF RF board has both the BPFs and LPFs, PA with 16HVF1 push-pull PA, RX-TX switching via diodes plus an SWR bridge.  Not sure of the board layout, but he does have separate relays for the LPF inputs and outputs.

I wonder if M0NKA would consider selling the RF board as a stand-alone kit...

Re: Harmonic performance - SSB vs CW

Kees T
 

An interesting exercise is to take the values for the Lo Band 80m LPF and compare the data between Farhan's LPF, Hans' LPF and the W3NQN LPF they are basically the same design, except the W3NQN LPF has 1 extra capacitor. Use a program like "Elsie" the student version is free and look at the results ......quite a difference. Hans has the best Return Loss numbers and W3NQN has by far the best rolloff and should readily meet FCC specs. 

I'll see if I can upload the results. The actual capacitor/inductor values are readily available on the ARRL website .....just look up "Second Harmonic Optimized Low-Pass Filters" by W3NQN. 

Should be easy to rework if you are interested but it needs testing with Farhan's relay scheme. T37 or T44 toroids are fine for 10W or less and so are 100V rated Ceramic MLCs.

73 Kees K5BCQ

Re: ND6T AGC and Click kit wiring notes

Eddie Esserman
 

One more question, folks:

I have one of later run V3 kits with socket mounted 2822M chipset.  It works fine, and is SOCKET mounted.  Wonder if anyone has played with a substitute that pops in and might offer some (audio level albeit) AGC?  Just a thought.  I dunno what's out there, and what has been tinkered with.

Eddie

Re: Harmonic performance - SSB vs CW

Glenn
 

mcHF Boards:- he does sell the bare 0.6 boards as  pair i think.  See order page, bottom.


On Tue, Aug 7, 2018 at 12:24 PM, RCBoatGuy wrote:
Actually, the more I look a the mcHF RF board schmatics, the more i think its a good solution for the BPF, PA, and LPF issues. The mcHF RF board has both the BPFs and LPFs, PA with 16HVF1 push-pull PA, RX-TX switching via diodes plus an SWR bridge.  Not sure of the board layout, but he does have separate relays for the LPF inputs and outputs.

I wonder if M0NKA would consider selling the RF board as a stand-alone kit...

Re: Need Help

Jack Purdum
 

On Monday, August 6, 2018, 4:37:38 PM EDT, bdunk@... <bdunk@...> wrote:


Thanks Jack,

I'm not sure what you are talking about, I just assumed I install the replacement encoder and it should work.

Where do I fine the 4.3 software?

Best regards, Bert VE3TYS

BITX40 LPF mod

Arv Evans
 

Hello

With all the filter discussion regarding uBITX I decided to take a look at design of
the output filter on the BITX-40.
LTspice IV - BITX_40__output_filter.asc_030.png
This LTSpice run shows that the stock LPF starts to roll off at about 8 MHz, which is
pretty good.  Problem is that the magic -43 db point does not come until about 21 MHz
or about the 3rd harmonic area.  Can this be imporoved...maybe.

LTspice IV - BITX_40__output_filter_with_parallel_resonance.asc_031.png
By adding just one capacitor across the output inductor we now get much more
attenuation at the 3rd harmonic point of 21 MHz.  By changing the value of C3
it is possible to move that point up or down in frequency.  This might be a way
to attenuate a specific harmonic or spur if it does not move about too much.

Next step is probably to scan the BITX-40 output to see if it really needs this type
of modification (how clean is it?).

It should also be possible to add a similar capacitor across the L6 inductor to have
another attenuation point.  That is a test for tomorrow because it is late and us old
guys need their beauty sleep.    8-)

NOTE: The upper trace in the pictures is frequency response.  The lower trace is phase
shift, which could be important if oscillation is encountered.  Note the sharp phase
shift at the parallel resonance point in the 2nd picture.

Arv  K7HKL
_._

Re: BITX40 LPF mod

Glenn
 

Arv,
I read somewhere that its a good idea to drop the inductor value by 25% or so, (cant recall exact %) then calculate the parallel Cap value for the required notch.  Otherwise i think the RL is compromised.
Or my memory is suspect, quite possible........
vk3pe

Re: BITX40 LPF mod

Arv Evans
 

Glen VK3PE

That is something that can be tested.  It doesn't show in the simulator, but real-world
may be different.  When I get to actually wiring this it will be easy to test.
Thanks for the info.

Arv
_._


On Mon, Aug 6, 2018 at 10:18 PM Glenn <glennp@...> wrote:
Arv,
I read somewhere that its a good idea to drop the inductor value by 25% or so, (cant recall exact %) then calculate the parallel Cap value for the required notch.  Otherwise i think the RL is compromised.
Or my memory is suspect, quite possible........
vk3pe

Re: One question only...

WaltR <waltrseiler@...>
 

Hello Bill,

Its very unfortunate that a well intended kit that was assembled with questionable quality parts, circuit and several other anomalies beyond my comprehension, is in its present quandary. The principals it appears, had good intentions and are to be commended for that. However, they have no authority in North America. In fact the Border agencies of both our countries are probably raising their eyebrows over the entire fiasco,  If not they soon will be. As I said earlier in my position As XO on board ship I can’t afford to run afoul of the authorities so my bitx 40 and ubitx have been destroyed. Sad really, I will be looking at the kits from QRP LABS. Or maybe I should purchase a good used FT817.
As an aside I had SIGINT techs look at the harmonic signature on the Harris, Wolfsburg and Bendix King gear and found them to exceed requirements by 30%, but of course again I’m comparing caviar to peanuts. My wife chastises me for my attitude ergo I’m at sea for 6 months of the year. I’m trying to do better hi hi. It’s no wonder I’m not allowed in the house before dark.

The sheer number of builders, the responses in this group, would suggest that there is a strong need for a simple affordable all band QRP rig, that is a fact, It will be interesting to see what happens in the next while.

In the research I have done there are some kits available from China, Russia and also Malaysia , they may be more in cost but perhaps ???


On a final observation you can buy all kinds of brands of test gear but there are only certain brands that are deemed to be certification instruments when operated by a certified knowledgeable technician, just because you go out and buy a Rigol
doesnt mean that now you are instantly an industry expert.

Early day tomorrow, anchors aweigh at 0400

cheers and 73
WRS

Re: BITX40 LPF mod

Jerry Gaffke
 

Don Cantrell ND6T documented this adjustment to the Bitx40 LPF in January of 2017:
    http://bitxhacks.blogspot.com/2017/01/nd6ts-suppression-of-pesky-2nd-harmonic.html


On Mon, Aug 6, 2018 at 09:14 PM, Arv Evans wrote:
With all the filter discussion regarding uBITX I decided to take a look at design of
the output filter on the BITX-40.

Re: One question only...

Timothy Fidler
 

Belay all that .. Japanese LPF cct sent to the VK who is designing a replacement board.  It gets 5 bands out of three signals ie 00 is also interpreted as a command. as usual old Timmo Fidler went off half cocked but at least the archives kicked in.

Re: One question only...

Christopher Miller
 

I wonder what the spurious emissions were like on this! The ARRL owns a spark gap transmitter that is housed in W1AW for what it is worth. They dont use it, though I think the time I was there they said they did once a year but whatever. I bet it is way worse than your uBitx. Enjoy!


On Mon, Aug 6, 2018 at 11:04 PM Timothy Fidler <engstr@...> wrote:
Belay all that .. Japanese LPF cct sent to the VK who is designing a replacement board.  It gets 5 bands out of three signals ie 00 is also interpreted as a command. as usual old Timmo Fidler went off half cocked but at least the archives kicked in.

Re: Harmonic performance - SSB vs CW

Timothy Fidler
 

before you rush in with the Tx Rx relay which does a lot of work sugggest you look at this


Adwww.digikey.co.nz/


the URL is humungous hence you need to look it up.

It shows a circuit for a source switching into one of two loads .. NOT what the Tcvr requires but SImilar

This Allison alluded to this circuit the one with the two diodes and said that POWER diodes can be used a five Watt level .  am not sure if the isol to the Rx will be enough. BUT if i does work it will be state of the art and cheaper than a click clack relay  RF IO switch only. 

There are plenty of two amp and more schottky diodes around for cheap as in 26 US cents or so. As I say see what Allison has in terms of proven design or perhaps just leave lands on the board so a user can surface mount TH parts or put in a relay as he prefers. 

SS switching of the RF for tx rx would be a big plus if it worked and would make the PCB very popular.


 I also have a proven UK speech compressor design schematic  only using a high brightness yellow diode etc total parts cost say around 8 AUD.  There is a VK3 hawking around his own "you beaut design" whereas this one is superior and  has variable gain and has been around for TWENTY years. 

 

Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885, 
Telephone Whangarei   022  691 8405
e: Engstr@...



----- Original Message -----
From:
BITX20@groups.io

To:
<BITX20@groups.io>
Cc:

Sent:
Mon, 06 Aug 2018 19:01:10 -0700
Subject:
Re: [BITX20] Harmonic performance - SSB vs CW


Thanks Tim.

I will Implement the diode switching to reduce IO ports required... or even go i2c bus? hmm...

Re: Harmonic performance - SSB vs CW

m5fra2@...
 

That is excellent Glenn, I never ceased to be amazed by this group.

 

Colin – M5FRA

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Glenn
Sent: 06 August 2018 23:42
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonic performance - SSB vs CW

 

More to see if it's possible rather than anything else, I was working on a PCB that would fit in same space as the original LPF area, but switching on both ends of each filter. (ie 3 more relays)  I didn't alter the actual switching sequence just added the extra relays controlled in the same manner as the original ones. Picture is of the PCB. No switching transistors are on the PCB, yet.  You can see space either side though.

This is not all routed as you can see, just the RF paths in and out of the relays. (The inductors are shown with 4 holes, just because i  had that part in my LIB.) Orientations may change.

glenn vk3pe

Re: Nextion Editor for Linux Mint ??

Tom, wb6b
 

Hi Nikos,

I downloaded the Nextion editor and tried to run it under Wine on my Mac. The first screen came up, but then it died. The console had lists of things it looked like it could not find. I'm interested in the Nextion display so at some point I put the effort into seeing if I can get it to run on the Mac. The Mac is not the same as Linux, but Wine tries to solve the same issue of running Windows programs as with Linux. If I recall the first time I tried to run the dot-net program I was successful with, Wine stopped and asked me if I wanted to install Mono; which I let it install.

I believe I downloaded Wine directly from the Wine site (https://www.winehq.org), as the versions that installed with Linux installers (and Mac installers like Homebrew) may be very old. 

The program I was able to get to run under Wine was: "/uBITX_MM_1.81/uBITX_Manager.exe".

The version of Wine I'm using is: "wine-3.0.1". It was called wine-stable.

I updated the SD card I was running on the Raspberry Pi, so my experiments with Wine on the Pi are gone. I'm looking around to see if I have any notes as to how I installed Wine. Some of the Raspberry Pi Wine packages rely on QEMU or other virtual machines. But I believe I installed something fairly simple, I may be mistaken (a VM could have been automatically installed), but I believe the uBITX_Manager ran directly on the Pi, by using the JIT compiler in the Mono runtime library. 

If you or anyone else finds a solution, please let us Linux/Mac folks know.

Tom, wb6b

Re: Harmonic performance - SSB vs CW

iz oos
 

Without adding other relays like omron g5 g6 and alike, maybe some might prefer just connect the outputs of the four filters to separate antenna outputs, one for each filter. Isn't more simple? Would it solve the harmonics issue?


Il 07/ago/2018 08:56, "m5fra2 via Groups.Io" <m5fra2=btinternet.com@groups.io> ha scritto:

That is excellent Glenn, I never ceased to be amazed by this group.

 

Colin – M5FRA

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Glenn
Sent: 06 August 2018 23:42
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonic performance - SSB vs CW

 

More to see if it's possible rather than anything else, I was working on a PCB that would fit in same space as the original LPF area, but switching on both ends of each filter. (ie 3 more relays)  I didn't alter the actual switching sequence just added the extra relays controlled in the same manner as the original ones. Picture is of the PCB. No switching transistors are on the PCB, yet.  You can see space either side though.

This is not all routed as you can see, just the RF paths in and out of the relays. (The inductors are shown with 4 holes, just because i  had that part in my LIB.) Orientations may change.

glenn vk3pe

Re: ND6T AGC and Click kit wiring notes

Timothy Fidler
 

Eddie E Lucky day with the socket  the TDA7052 is your friend AGC is built in . I believe Futurlec.com  may still sell it if so it will be just pennies and F does not have any MOQ as far as I know. Never buy just one. Perhaps Leon as per below might do you a deal on two chips (but if he has inventory problems he won't . Don't muck him around. I need him.). May not be pin compat (you work it out ). well you can use a machined pin IC socket to bring out the existing socket to a piece of Veroboard and wing it.  Now look up Ozqrp.com  Find your way to the MST 3 schema via the documents section.   Look at audio section of the schematic . AGC Is is all there. Leon in NSWales . He is owner of Ozqrp has been doing AGC as std on his monobanders for  6 years and he only lives at the bottom of the world !!! .

Notice the L08 reggy driving the TDA... that is because Leon is a Pro. and checks this stuff out.  he has an interesting reversed voltage protection on his PCB too.  No fuse , no crowbar and essentially no voltage drop. 

Re: ND6T AGC and Click kit wiring notes

Timothy Fidler
 

..WARNING WArning.re chip subs for audio ref Eddie E - the TDA 7052AT is what Leon used. the  A and non A suffix versions are different in volume control area. Stick with Leon's AGC concept  if you go this way.                  https://www.nxp.com/docs/en/data-sheet/TDA7052A_AT.pdf

Re: Harmonic performance - SSB vs CW

William R Maxwell
 

Can anybody explain why I am not receiving Glenn's posts on this subject but I am receiving the responses he receives, such as this from Colin. Yet, if  I go to the group page to view Colin's reply, I can step back to find Glenn's post. Why should they not be appearing as emails, as they had previously, since we moved to groups.io

Bill, VK7MX


On 7/08/2018 4:56 PM, m5fra2 via Groups.Io wrote:

That is excellent Glenn, I never ceased to be amazed by this group.

 

Colin – M5FRA

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Glenn
Sent: 06 August 2018 23:42
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonic performance - SSB vs CW

 

More to see if it's possible rather than anything else, I was working on a PCB that would fit in same space as the original LPF area, but switching on both ends of each filter. (ie 3 more relays)  I didn't alter the actual switching sequence just added the extra relays controlled in the same manner as the original ones. Picture is of the PCB. No switching transistors are on the PCB, yet.  You can see space either side though.

This is not all routed as you can see, just the RF paths in and out of the relays. (The inductors are shown with 4 holes, just because i  had that part in my LIB.) Orientations may change.

glenn vk3pe