Topics

bitx20 problems #bitx20help

dries breughe
 

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.

Ashhar Farhan
 

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.

Evan Hand
 

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

Jerry Gaffke
 

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:
  http://www.hfsignals.com/index.php/bitx40/ 

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.

dries breughe
 

the diagram

Jerry Gaffke
 

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:
  http://www.phonestack.com/farhan/bitx.html

(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

Arv Evans
 


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

dries breughe
 



Van: BITX20@groups.io <BITX20@groups.io> namens Ashhar Farhan <farhanbox@...>
Verzonden: zondag 18 augustus 2019 20:22
Aan: BITX20@groups.io <BITX20@groups.io>
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.

dries breughe
 


https://www.youtube.com/watch?v=NWi5he7hpZw
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: BITX20@groups.io <BITX20@groups.io> namens Ashhar Farhan <farhanbox@...>
Verzonden: zondag 18 augustus 2019 20:22
Aan: BITX20@groups.io <BITX20@groups.io>
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.

dries breughe
 

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

here the circuit of the hf amplifier

Ashhar Farhan
 

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

 

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:  http://golddredgervideo.com/kc0wox/  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