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Re: bitx20 problems #bitx20help

Mark - N7EKU
 

Hi Dries,

It looks like you have been working hard on this.? Good job to get this far!? It is much harder to work from scratch, than to build a kit, but you can learn a lot!

This site:? ? is probably your best resource.? OM KC0WOX does a great job of explaining a lot about the kit and shows many measurements done with a homemade RF probe and also has a lot of videos of the various signals on an oscilloscope.? I hope this can help you diagnose your trouble.

You used six 2n2018 for your HF amp, I assume you are using Farhan's schematic for that?

What diode are you asking about for the 1n4001.

I'm not sure that the ne602 has enough power to drive the final amp all by itself.

FT37-43 is just what you want for all the broadband transformers used in the radio.? Do not use them for the final low pass filter -- you need powdered iron cores for that.

Your VFO and BFO signals should look clean like in the linked site's videos.? Be sure to have your scope probe on the proper test point, and use a 10:1 probe if possible.

From your video, sometimes it seems like your scope has a problem as the signal is not blanking on the trace return?? This can make good signals look bad.

Be sure when you are posting questions here, that you specificy where your test points are for your measurements.? This can help us understand your questions and measurements better.

73,


Mark -- N7EKU/VE3
Re: Help #arduino

 

The short answer is yes, if you add the screen features you want to the Arduino firmware.? I am not aware of any such firmware available.? There is also a shortage of I/O in the stock Raduino.?

I would suggest that you first look at the Nextion display work that can be found here:??

Dr. Lee has written software and screen designs to work with the Nano that came with the uBitx.? With all the added features, there is very little room for more modifications in the Nano code.? You do need to purchase a Nextion display with touch screen capability.?? Be sure to verify the screen size and the enhanced version with touch capabilities to work with the KD8CEC software.? I used both the 2.4 and 3.2 inch enhanced versions.? Available from multiple vendors.

There is the also JackAl add on board that did change the processor to one with more memory and speed.? That is available here:?? This has higher capabilities, at a higher price.? Be sure to note that the listed price for the board does not include every thing that you need to make it work.

You can go the route of converting the Nano code to a larger/more powerful processor like the Teensy on the JackAL board or other newer Arduino based system.? Regardless, that will be a significant effort.? Would be curious to see any results that you come up with.

73
Evan
AC9TU
Re: bitx20 problems

 

Dries,

Here's what I hope is a helpful answer to your questions about the Bitx20

Yes, you could use FT-37-43 cores on the transformers.
Just duplicate the transformers used on the Bitx40, 10 turns trifilar:
? ??

Carrier suppression on transmit mostly depends on T3 and the two nearby diodes
being wired correctly, also the nearby 100 ohm pot must be adjusted for best suppression.
The crystal filter will then improve on this somewhat, assuming the BFO is adjusted correctly.

Curt's suggestion to check the BFO placement is a good one.
Have you tried adjusting the 22pF trimmer in parallel with L3?
There's a whole paragraph about tuning in the BFO on? ?
? ??
starting with the words "On amateur bands above ..."

Here's a technique for debugging a receiver that might prove useful:
??
Farhan uses a short piece of wire as an antenna, perhaps 1 meter long.
It picks up houshold QRM, and he injects that into various parts of the radio,
listening to the result out of the speaker.? Perhaps this will help.

Once the receiver mostly works,?you might verify the crystal filter shape.
To do this, measure the audio coming out to the speaker using a scope
while tuning through a strong carrier in one of the bands.??
Ideally, you would start hearing it around 300 hz on one side of the carrier,?
it shouldould quickly rise up to full volume and stay there till around 2500 hz,
at which point the volume should rapidly fall into oblivion again.

I am not quite sure what to say about all of the "mixing frequency products"
that you hear in the receiver.? I don't know how clean this radio was,
but they should not get in the way of casually tuning in stations across the band.
It could be just a matter of a wiring error or bad part.
Or it could depend on how the parts were placed on the board.

When building the crystal filter, it is best to choose a set of?
four 10mhz crystals that match in frequency within perhaps 100hz
when plugged into an oscillator, using a frequency counter.? ?
It may be necessary to do this if the above test of the filter shape looks wrong.

We can worry about Q14 and the 2n2218 JBOT power amp
after you get the receiver working properly.
?
If you get stuck, you can certainly ask questions here.
But best would be to find a local club of radio amateurs who know
about working on radios and have appropriate test equipment.
Perhaps someone there would like to help.

Best Regards,
Jerry Gaffke, KE7ER


On Sun, Aug 18, 2019 at 05:29 PM, Curt wrote:
hard to quickly resolve how many issues remain with your build.? on receive - I wonder if BFO is properly adjusted.? note this oscillator must be appropriately adjusted to mix the RF into the crystal filter to provide the correct audio.?

most everyone here is okay with buying a bitx or ubitx board from India, and wiring it up.? there are still modifications to consider.? if you must build a rig - I suggest visiting QRP-LABS.com.?

Re: Reduced power on 40 meters. #ubitx #v5

 

Brad,

In the past every time that issue has been seen it was the 40 low pass filter having
wrong components installed at assembly.? Other wise the issue would be evident
on other bands.

Generally the power goes down as one goes up from 80 through to 10M.
Nominally 40m should be less than 80 and more than 20.? This is assignable
to the power amp.?

If 40 is much lower than 20 then low pass filter or switching is broken.

Allison
Re: bitx20 problems #bitx20help

 

Dries,
I remember you mentioning that you had changed things around. The one you posted is exactly the original. Can you post your own version' diagram?
Second, what kind of equipment do you have to troubleshoot? Do you have access to an oscilloscope or an rf power meter?

- f


On Mon 19 Aug, 2019, 1:40 AM dries breughe, <driesbreughe@...> wrote:
the circuit is from the transceiver has already been posted and is on your own website.

here the circuit of the hf amplifier
Re: bitx20 problems

 

OM

hard to quickly resolve how many issues remain with your build.? on receive - I wonder if BFO is properly adjusted.? note this oscillator must be appropriately adjusted to mix the RF into the crystal filter to provide the correct audio.?

most everyone here is okay with buying a bitx or ubitx board from India, and wiring it up.? there are still modifications to consider.? if you must build a rig - I suggest visiting QRP-LABS.com.?

my ubitx is receiving as I type - and I confess to having a Yaesu but it has been off several days.

73 Curt
Re: Help #arduino

 

Senior OM

fine news on your successful build.? I think you refer to a larger LCD display?? there are 2 custom versions of uBITX software but I think they only work with color displays - others can correct me if I am wrong.? even if that display can connect to ubitx, the firmware will not likely support it.?

I use the simple 2 line LCD and it works nice enough.?

enjoy your ubitx and I hope to QSO

Curt WB8YYY
Help #arduino

[email protected]
 

I am han radio from cuba. I build the Ubitx and working fine. The questions is?
I can use GLCD 32160 to put un my Ubitx
Re: bitx20 problems

 

Ham since '07, building a Bitx20 in '12? OK, have you built simpler in between? That should have taught you the basics of troubleshooting and given you some basic test-gear.
A Bitx2o from scratch is NOT a beginner's project!
I'd recommend a careful perusal of SolderSmoke blog: Bill N2CQR in particular is a consummate builder, returning to the simple and re-starting just for the joy of it - and Pete N2CQW doing real advanced stuff, again for the joy of it. IIRC Bill built bitxes before Farhan's kits - merely as proof-of-concept.

73
Dex ZL2DEX
Re: VOX Issues to be aware of. Or, suspected new digital mode.

 

On Sun, Aug 18, 2019 at 05:33 AM, bobolink wrote:
ripped from CODEC2
CODEC2 looks interesting. It seems to be a breath new life for older research and makes it work well thanks to modern DSP technology. The original researchers could not get past a certain technology point.

Well unless you have a government sized budget.?


If you think learning Morse Code is hard, imagine learning this keyboard. Maybe someone should come up with a Vocoder Code Tutor. Must have the lowest bit rate for any digital voice mode.


Probably could send voice at WSPR bit rates. Imagine that, voice WSPRing.

Looks like FreeDV (based on CODEC2) can be implemented with one of the more powerful STM32 processors, maybe one of the newer Teensy boards. Might be fun to add digital voice to the uBitx.


Well, if the snoring VOX issue cannot be solved, maybe just some kind of auto ID every 10 minutes to keep his transmissions legal.

Tom, wb6b

?
Re: bitx20 problems #bitx20help

 

¿ªÔÆÌåÓý

the circuit is from the transceiver has already been posted and is on your own website.

here the circuit of the hf amplifier

jbot.gif

Re: bitx20 problems #bitx20help

 

¿ªÔÆÌåÓý
vfo van 4Mhz tot 4.350Mhz Je ziet dat ik de aan de tuning condensator draai. de vfo is niet overal proper. ik zoek nog naar de oorzaak.
www.youtube.com

Van: [email protected] <[email protected]> namens Ashhar Farhan <farhanbox@...>
Verzonden: zondag 18 augustus 2019 20:22
Aan: [email protected] <[email protected]>
Onderwerp: Re: [BITX20] bitx20 problems #bitx20help
?
Can you post a circuit diagram of your effort? Possibly with a picture of your build too? What kind of test gear do you have access to?

On Sun 18 Aug, 2019, 11:34 PM , <driesbreughe@...> wrote:
I have been a radio amateur since 2007.
over the years I have made many contacts worldwide? using comercile radios like ts-450 and ic-703.
because that is the easy way.
nevertheless, I always thought that was a bit of cheating, a shared honor with icom and kenwood.
there is a lot to be found on the internet concerning homemade transceivers.
on some websites you see diagrams, explanations, photos.
sometimes it all looks so simple. like you just build the simple circuit and you're done.
But that is not my experience. sometimes I think it's a bad design or I'm just a stupid builder
in 2012 i started building the bitx20. clean with a printed circuit board that I had made.
it was many years and failed project, But now I? want to make an attempt to finish it
the receiver works, but not completely clean. I hear many mixing frequency products.
the recipient was deaf. in ssb they were only very strong stations. who came through it.
the transmitter: almost no carrier suppression
the pre hf amplifier (q14) functions as an attenuator.
i am not sure regarding the rf transformers. TV balun core is a vague description. Can it also function well with a ft37-43?
i also built the hf amplifier with? 6?? 2n2018 transistors.
i used an hf oscilator (ne602 with a bit of external gain) to test the hf amplifier.
there was power gain, I had 250mW not the expected 5W
it is not specified which diode it must be.
I managed to get a 1N4001 in it
I hope you can give some advice in the hope of resolving technical issues.
Re: bitx20 problems #bitx20help

 

¿ªÔÆÌåÓý



Van: [email protected] <[email protected]> namens Ashhar Farhan <farhanbox@...>
Verzonden: zondag 18 augustus 2019 20:22
Aan: [email protected] <[email protected]>
Onderwerp: Re: [BITX20] bitx20 problems #bitx20help
?
Can you post a circuit diagram of your effort? Possibly with a picture of your build too? What kind of test gear do you have access to?

On Sun 18 Aug, 2019, 11:34 PM , <driesbreughe@...> wrote:
I have been a radio amateur since 2007.
over the years I have made many contacts worldwide? using comercile radios like ts-450 and ic-703.
because that is the easy way.
nevertheless, I always thought that was a bit of cheating, a shared honor with icom and kenwood.
there is a lot to be found on the internet concerning homemade transceivers.
on some websites you see diagrams, explanations, photos.
sometimes it all looks so simple. like you just build the simple circuit and you're done.
But that is not my experience. sometimes I think it's a bad design or I'm just a stupid builder
in 2012 i started building the bitx20. clean with a printed circuit board that I had made.
it was many years and failed project, But now I? want to make an attempt to finish it
the receiver works, but not completely clean. I hear many mixing frequency products.
the recipient was deaf. in ssb they were only very strong stations. who came through it.
the transmitter: almost no carrier suppression
the pre hf amplifier (q14) functions as an attenuator.
i am not sure regarding the rf transformers. TV balun core is a vague description. Can it also function well with a ft37-43?
i also built the hf amplifier with? 6?? 2n2018 transistors.
i used an hf oscilator (ne602 with a bit of external gain) to test the hf amplifier.
there was power gain, I had 250mW not the expected 5W
it is not specified which diode it must be.
I managed to get a 1N4001 in it
I hope you can give some advice in the hope of resolving technical issues.
Reduced power on 40 meters. #ubitx #v5

 

Hi, I have the ubitx V5 board, and have reduced power on 40 meters.

All other bands/frequency ranges? are fine. I am getting 10 or more watts out everywhere but 40 has about 6 watts.
At tp7 before the filters looking at it in the scope, it is reduced relative to other bands as well..so not output filter related.
Anybody run into this?
73
Brad N8YG
Re: bitx20 problems #bitx20help

 


The original BITX:


Arv? K7HKL
_._


On Sun, Aug 18, 2019 at 12:35 PM Evan Hand <elhandjr@...> wrote:
Knowing that I might open a can of worms, here I go:

I have been monitoring this group for almost a year now, and have not seen any information posted on the original BITX20 during that time.? I also did a search on the files section and could not find information there, except on how to modify a BITX20 3 series to be multi band. Granted that I used BITX20 for the filter, and there may be a better choice.? Even the history document is not clear on what the early designs were for the BITX series.? I would assume that the design that you built is VFO controlled, rather than Si5351 based similar to the original BITX40 that later was modified to include the Raduino with Si5351.

There hopefully are others on the feed that did work with the original BITX20 that might make sense of your questions.? For me, I would need the schematics at least.? I would suggest that you point us to the information that you have on that original design so that we could make suggestions.

Alternatively, wait and hope someone that worked on the version that you built can chime in.


73 and hope someone can help you.
Evan
AC9TU

Re: bitx20 problems #bitx20help

 

Ah, I see that Farhan responded, you're in good hands.
The only problem I see is that he will tell you how easy it is.
Which for him, it is, as he has debugged plenty of these radios.

He might even enjoy dredging up a few dim memories from his distant youth:
??

(Having written that, did a quick check and found your post of the schematic.
Exactly the one from the webpage above, created some 25 years ago.)??

Jerry
Re: bitx20 problems #bitx20help

 

¿ªÔÆÌåÓý

the diagram

bitx.gif

Re: bitx20 problems #bitx20help

 

That's a very long list of trouble.
And? a rather old Bitx design.
Most folks in this forum are now using either the Bitx40 or the uBitx from hfsignals.com.

> sometimes it all looks so simple.?like you just build the simple circuit and you're done.
> But that is not my experience.?


Radio circuits are seldom simple to get working well, especially if you don't have
a couple thousand dollars worth of test gear and 40 years experience with it.
And sometimes, even when you do.
Even for stuff considerably more simple than your Bitx20.
A complete superhet SSB transceiver is definitely not simple,
though the Bitx design is getting close to being as simple as possible.

I suggest you get a $59 Bitx40 working, that might prove challenging enough:
???

If you really want to get this older Bitx20 working, you need to tell us which set of?
instructions you are working from, what you did different, where you had questions,
post a few photos, describe the test gear you have at hand, and a full description
of each problem as you take them one at a time.? Assume months, given your
initial description. And likely involve at least having a DVM and a 10mhz scope
(preferably better) and something like the Antuino available to help debug it.
Just getting the crystal filter to behave properly and the VFO stable enough
may prove to be significant "learning opportunities".

Jerry, KE7ER? ? Flora OR



On Sun, Aug 18, 2019 at 11:04 AM, <driesbreughe@...> wrote:

I have been a radio amateur since 2007.
over the years I have made many contacts worldwide? using comercile radios like ts-450 and ic-703.
because that is the easy way.
nevertheless, I always thought that was a bit of cheating, a shared honor with icom and kenwood.
there is a lot to be found on the internet concerning homemade transceivers.
on some websites you see diagrams, explanations, photos.
sometimes it all looks so simple. like you just build the simple circuit and you're done.
But that is not my experience. sometimes I think it's a bad design or I'm just a stupid builder
in 2012 i started building the bitx20. clean with a printed circuit board that I had made.
it was many years and failed project, But now I? want to make an attempt to finish it
the receiver works, but not completely clean. I hear many mixing frequency products.
the recipient was deaf. in ssb they were only very strong stations. who came through it.
the transmitter: almost no carrier suppression
the pre hf amplifier (q14) functions as an attenuator.
i am not sure regarding the rf transformers. TV balun core is a vague description. Can it also function well with a ft37-43?
i also built the hf amplifier with? 6?? 2n2018 transistors.
i used an hf oscilator (ne602 with a bit of external gain) to test the hf amplifier.
there was power gain, I had 250mW not the expected 5W
it is not specified which diode it must be.
I managed to get a 1N4001 in it
I hope you can give some advice in the hope of resolving technical issues.
Re: bitx20 problems #bitx20help

 

Knowing that I might open a can of worms, here I go:

I have been monitoring this group for almost a year now, and have not seen any information posted on the original BITX20 during that time.? I also did a search on the files section and could not find information there, except on how to modify a BITX20 3 series to be multi band. Granted that I used BITX20 for the filter, and there may be a better choice.? Even the history document is not clear on what the early designs were for the BITX series.? I would assume that the design that you built is VFO controlled, rather than Si5351 based similar to the original BITX40 that later was modified to include the Raduino with Si5351.

There hopefully are others on the feed that did work with the original BITX20 that might make sense of your questions.? For me, I would need the schematics at least.? I would suggest that you point us to the information that you have on that original design so that we could make suggestions.

Alternatively, wait and hope someone that worked on the version that you built can chime in.


73 and hope someone can help you.
Evan
AC9TU
Re: bitx20 problems #bitx20help

 

Can you post a circuit diagram of your effort? Possibly with a picture of your build too? What kind of test gear do you have access to?


On Sun 18 Aug, 2019, 11:34 PM , <driesbreughe@...> wrote:
I have been a radio amateur since 2007.
over the years I have made many contacts worldwide? using comercile radios like ts-450 and ic-703.
because that is the easy way.
nevertheless, I always thought that was a bit of cheating, a shared honor with icom and kenwood.
there is a lot to be found on the internet concerning homemade transceivers.
on some websites you see diagrams, explanations, photos.
sometimes it all looks so simple. like you just build the simple circuit and you're done.
But that is not my experience. sometimes I think it's a bad design or I'm just a stupid builder
in 2012 i started building the bitx20. clean with a printed circuit board that I had made.
it was many years and failed project, But now I? want to make an attempt to finish it
the receiver works, but not completely clean. I hear many mixing frequency products.
the recipient was deaf. in ssb they were only very strong stations. who came through it.
the transmitter: almost no carrier suppression
the pre hf amplifier (q14) functions as an attenuator.
i am not sure regarding the rf transformers. TV balun core is a vague description. Can it also function well with a ft37-43?
i also built the hf amplifier with? 6?? 2n2018 transistors.
i used an hf oscilator (ne602 with a bit of external gain) to test the hf amplifier.
there was power gain, I had 250mW not the expected 5W
it is not specified which diode it must be.
I managed to get a 1N4001 in it
I hope you can give some advice in the hope of resolving technical issues.
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