Topics

#bitx40help BITX40 LSB Winlink #bitx40help

Daniel Crane
 

I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV



M Garza <mgarza896@...>
 

Gordon Gibby seems to be the Winlink guru.  I am sure he will chime in.
Why do you not want to upgrade your Bitx40 to do USB?  It doesn't sound very difficult.  
Allard worked very hard to make it as painless as possible.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 7:39 PM, Daniel Crane <danjamitch@...> wrote:
I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV




Daniel Crane
 

I thought that requires one to move the BFO to the other not quite as steep skirt of the ladder.

Dan

On Mon, Mar 26, 2018 at 5:47 PM, M Garza <mgarza896@...> wrote:
Gordon Gibby seems to be the Winlink guru.  I am sure he will chime in.
Why do you not want to upgrade your Bitx40 to do USB?  It doesn't sound very difficult.  
Allard worked very hard to make it as painless as possible.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 7:39 PM, Daniel Crane <danjamitch@...> wrote:
I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV





Gordon Gibby
 

Daniel crane, you will have to put it on upper side band in  order to make WINLINK work.  While FLDI G.I. is able to invert the tones of PSK 31 to accommodate rigs stuck in lower sideband, WINLINK modem protocols do not have that ability.

There have been a couple of folks here who have written improved software, and I think it is available on Bitx X.net or something similar.  See the long list of web addresses at the end of each message.

Once you learn how to upload that software through the little USB port on the Arduino, using the free integrated development environment, life will be much easier for you.   It’s been a while, but I think I took one of their versions and modified it a bit for myself, and it works very nicely.

I’ve made a boatload of WINLINK connections using the bit X 40 and or MicroBitx 

I don’t know what gateway you’re trying to connect to, but if you telephone the systems operator for the gateway they will often help you.

Gordon


On Mar 26, 2018, at 20:47, M Garza <mgarza896@...> wrote:

Gordon Gibby seems to be the Winlink guru.  I am sure he will chime in.
Why do you not want to upgrade your Bitx40 to do USB?  It doesn't sound very difficult.  
Allard worked very hard to make it as painless as possible.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 7:39 PM, Daniel Crane <danjamitch@...> wrote:
I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV




Gordon Gibby
 

I think the typical way people do it is to flip the VFO oscillator , and although the skirt might not be so wonderful, it works.


On Mar 26, 2018, at 22:08, Daniel Crane <danjamitch@...> wrote:

I thought that requires one to move the BFO to the other not quite as steep skirt of the ladder.

Dan

On Mon, Mar 26, 2018 at 5:47 PM, M Garza <mgarza896@...> wrote:
Gordon Gibby seems to be the Winlink guru.  I am sure he will chime in.
Why do you not want to upgrade your Bitx40 to do USB?  It doesn't sound very difficult.  
Allard worked very hard to make it as painless as possible.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 7:39 PM, Daniel Crane <danjamitch@...> wrote:
I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV





M Garza <mgarza896@...>
 

Daniel,
Have look here:  https://github.com/amunters/bitx40.  There are complete instructions on how to upgrade the software and make the necessary modifications to get USB and much more.
The BFO is adjusted via software.  There are a few hardware mods, but they are minimal and not all are needed to get USB.

Hope this helps.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 9:44 PM, Gordon Gibby <ggibby@...> wrote:
I think the typical way people do it is to flip the VFO oscillator , and although the skirt might not be so wonderful, it works.


On Mar 26, 2018, at 22:08, Daniel Crane <danjamitch@...> wrote:

I thought that requires one to move the BFO to the other not quite as steep skirt of the ladder.

Dan

On Mon, Mar 26, 2018 at 5:47 PM, M Garza <mgarza896@...> wrote:
Gordon Gibby seems to be the Winlink guru.  I am sure he will chime in.
Why do you not want to upgrade your Bitx40 to do USB?  It doesn't sound very difficult.  
Allard worked very hard to make it as painless as possible.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 7:39 PM, Daniel Crane <danjamitch@...> wrote:
I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV






Daniel Crane
 

Hey, thanks, Gordon.  I'm on it.

If anybody can spare me the search for the link, I'd dearly appreciate it.

Dan

On Mon, Mar 26, 2018 at 7:42 PM, Gordon Gibby <ggibby@...> wrote:
Daniel crane, you will have to put it on upper side band in  order to make WINLINK work.  While FLDI G.I. is able to invert the tones of PSK 31 to accommodate rigs stuck in lower sideband, WINLINK modem protocols do not have that ability.

There have been a couple of folks here who have written improved software, and I think it is available on Bitx X.net or something similar.  See the long list of web addresses at the end of each message.

Once you learn how to upload that software through the little USB port on the Arduino, using the free integrated development environment, life will be much easier for you.   It’s been a while, but I think I took one of their versions and modified it a bit for myself, and it works very nicely.

I’ve made a boatload of WINLINK connections using the bit X 40 and or MicroBitx 

I don’t know what gateway you’re trying to connect to, but if you telephone the systems operator for the gateway they will often help you.

Gordon


On Mar 26, 2018, at 20:47, M Garza <mgarza896@...> wrote:

Gordon Gibby seems to be the Winlink guru.  I am sure he will chime in.
Why do you not want to upgrade your Bitx40 to do USB?  It doesn't sound very difficult.  
Allard worked very hard to make it as painless as possible.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 7:39 PM, Daniel Crane <danjamitch@...> wrote:
I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV





Daniel Crane
 

That was quick.

On Mon, Mar 26, 2018 at 7:54 PM, M Garza <mgarza896@...> wrote:
Daniel,
Have look here:  https://github.com/amunters/bitx40.  There are complete instructions on how to upgrade the software and make the necessary modifications to get USB and much more.
The BFO is adjusted via software.  There are a few hardware mods, but they are minimal and not all are needed to get USB.

Hope this helps.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 9:44 PM, Gordon Gibby <ggibby@...> wrote:
I think the typical way people do it is to flip the VFO oscillator , and although the skirt might not be so wonderful, it works.


On Mar 26, 2018, at 22:08, Daniel Crane <danjamitch@...> wrote:

I thought that requires one to move the BFO to the other not quite as steep skirt of the ladder.

Dan

On Mon, Mar 26, 2018 at 5:47 PM, M Garza <mgarza896@...> wrote:
Gordon Gibby seems to be the Winlink guru.  I am sure he will chime in.
Why do you not want to upgrade your Bitx40 to do USB?  It doesn't sound very difficult.  
Allard worked very hard to make it as painless as possible.

Marco - KG5PRT

On Mon, Mar 26, 2018 at 7:39 PM, Daniel Crane <danjamitch@...> wrote:
I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV







Joe Puma
 

I thought the b40 has USB with the latest version Allard’s? sketch. I’ve used my bitx40 with wsjtx which needs USB too. Winlink should work for you. 



On Mar 26, 2018, at 8:39 PM, Daniel Crane <danjamitch@...> wrote:

I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV



Daniel Crane
 

Thanks Joe.  Yup, Allard's sketch.  That's what I got from Marco and Gordon's posts.

Just to recite my new understanding, for those like me whose facility with superhet design strays just into and out of visibility -

The magic is in the ladder/BFO combination, which shears off the carrier and unwanted sideband, while passing the wanted sideband.  This is not touched in Allard's sketch.  So...  if you use, say, a 10MHz IF, then  3 MHz BFO will get you 7MHz LSB and a 4 MHz BFO will get you 14MHz USB.  Of course you have to filter to make sure you have signal content where you want it to look.

To get 7MHz USB you need a BFO at (drumroll) 17 MHz.  You have to point the ladder at -7Mhz in order to get the mirror image sideband.  Am I right?

Dan

On Mon, Mar 26, 2018 at 9:49 PM, Joe Puma <kd2nfc@...> wrote:
I thought the b40 has USB with the latest version Allard’s? sketch. I’ve used my bitx40 with wsjtx which needs USB too. Winlink should work for you. 



On Mar 26, 2018, at 8:39 PM, Daniel Crane <danjamitch@...> wrote:

I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV




M Garza <mgarza896@...>
 

Daniel,
Your understanding is correct.
We have a 12 MHz IF.  5 MHZ BFO gives us a 7 MHZ LSB signal and a 19 MHZ BFO gives us a 7 MHZ USB signal.  The IF & filter are constant.  In our case, the BFO is moved to either side of the ladder filter to change side bands.

Marco - KG5PRT 

On Tue, Mar 27, 2018, 8:47 AM Daniel Crane <danjamitch@...> wrote:
Thanks Joe.  Yup, Allard's sketch.  That's what I got from Marco and Gordon's posts.

Just to recite my new understanding, for those like me whose facility with superhet design strays just into and out of visibility -

The magic is in the ladder/BFO combination, which shears off the carrier and unwanted sideband, while passing the wanted sideband.  This is not touched in Allard's sketch.  So...  if you use, say, a 10MHz IF, then  3 MHz BFO will get you 7MHz LSB and a 4 MHz BFO will get you 14MHz USB.  Of course you have to filter to make sure you have signal content where you want it to look.

To get 7MHz USB you need a BFO at (drumroll) 17 MHz.  You have to point the ladder at -7Mhz in order to get the mirror image sideband.  Am I right?

Dan

On Mon, Mar 26, 2018 at 9:49 PM, Joe Puma <kd2nfc@...> wrote:
I thought the b40 has USB with the latest version Allard’s? sketch. I’ve used my bitx40 with wsjtx which needs USB too. Winlink should work for you. 



On Mar 26, 2018, at 8:39 PM, Daniel Crane <danjamitch@...> wrote:

I am trying to find a way to connect to Winlink with my BitX40.

I have one of the last Bitx40's shipped, in late November, just before the ubitx started to arrive.  Another fellow whose name I cannot recall got one at the same time and had a lot of difficulty getting it going.  The group here helped him along and over a period of weeks got him up and running.  Just at the conclusion of that process he reported that he had that day made successful Winlink connections.  From the context and timing he would not have converted his BitX 40 to USB.

Does anybody here know if it is possible to connect to Winlink on lower sideband?  I've tried WINMOR, ARDOP, and VARA, but no joy.  No RMS answers my calls.  I have made a number of PSK-31 QSO's between here (LA) and stations as far away as Washington state, so I know my radio works.  I decode RTTY and Olivia as well.

I posted this question on the Winlink group and got the school answer, "Winlink requires USB".

I uptune so as to match 1500Hz center frequencies.  And I uptune 700Hz more because my BitX isn't calibrated.  Occasionally I get lucky and see an RMS engaged  in a session and center that signal. I patiently tune in 100Hz increments.

But still no joy.  Any ideas, other than move on to USB?

Thanks/Dan
KM6GRV




Jack Margolis <jmargolis9@...>
 

I'm still confused on how to change the frequency of the Radiuno that is supplied with the Bitx40 kit.

Does one need to edit the sketch of push buttons on the Radiuno.  I've looked at the firmware and it shows the bottom and top range of the two VFOs.   

I am also not sure about setting the BFOs, etc to give me USB on 20 Meters.  I want to buy a 40 meter Bitsx change the two filters ....then do whatever to the Raduino.

Thanks in advance for your help.   73   Jack  

Timothy Fidler
 

JM there is a whole lot of information here around this BBS in various corners.  see right down bottom of this post...
(public version of post sent privately a while back) 
Extra filters can come from Kees Talen who sells little PCBs for this purpose .  Moto appn note AN267 is  your friend for this design.  KT sells parts .. you do the design.

you will need to change out the IRF PA for a  proper Mitsi HF or VHF Mosfet. The pinouts don.'t align as Flowers found out but he worked out a kludge - eg wiring the RF transformer direct to the drain of the RDHH16.  The fact that the  Source and tab on the RDHH16 and 15 Mosfets are the same simplifies some of the rework and of course makes heat sinking a lot easier. Those Mosfets are avail at reasonable prices as in just over 5 usd plus freight from "cecil the parts place". DIZ,  the toroid king used to stock them but >....no more.

  There is a V2 version two that involves hardware mods- BEWARE.  Best have a backup plan like a second Raduino or a clone so you can always fall back to plan A.
 
https://github.com/amunters/bitx40   is a new load of software that may do many things you want. It also contains a whole lot of fixes and includes CW capability.

In terms of display for both 40 and 20 m with a dual band design (??)  this item (search for 6 digit freq counter) from www.mpja.com might solve your problem $13 USD without a recode job. you use the frequency counter in native mode to display frequency in 20m operation and the original Bitx display for 40 m operation  (sounded like a good idea at the time ).

Type 43 material is pretty lossy above  7 Mhz.(can forward data) there are magnetics which if you change  them out will make a difference.   Flowers got 6W out he says with only the Mosfet change.  Without that change he was getting less than 2 W out.

MOtorola design note AN267 is your friend for  designing the New output filter.  (Kees supplies parts not designs)
===============================================================================
With six watts you can drive plenty of amps that will give you 50W+  out 

https://www.youtube.com/watch?v=Ki_z6dl9xgo&t=263s

Just The guts of this amp come up from time to time on Ebay as just PCBs all ready to go but no case  for region of $80 USD. It uses an MRF-186 dual RF mosfet  ..beware imitations esp beware of SMPS mosfet kits .  Crude as hell but it works and is hard to kill it seems. Somebody in PRC obviously lucked into a whole lot of surplus Motorola parts at bargain prices

There are some reviews of it on Austr. websites./blogsites 
======================================================================================

https://groups.io/g/BITX20/topic/bitx40_convert_to_20_meters/5162026?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,5162026

ajparent1/KB1GMX
 

First the code (Arduino sketch)had to be changes to set the 5351 to the needed range for 20M.
That is both the LO and the BFO as needed.  You will need the 40M sketch to do that.

The 40M band pass filter gets changed to 20M, Look for the schematic of the older bitx20
series for values.

Then the 40M low pass filter needs to be changed.

Ignore any noise about changing the IRF510s.  I have run those to over 70mhz at 
high power (20W at 13.8V).   Its a competent enough device assuming the circuit
around it is correct.

>>The magic is in the ladder/BFO combination, which shears off the carrier and unwanted sideband, while passing the wanted sideband.  

Only half true.  The balanced modulator is to remove the carrier, the filter passes the desired
sideband (strips the other).

Allison


Jerry Gaffke
 

The Bitx40 works just fine on 40m with the IRF510, no need for major surgery.
Also, no issues with spurious emissions (an issue for the uBitx). 

Best to get started using the Bitx40  with stock firmware and no mods.
But as you may have discovered, the frequency jumps around a bit, and USB operation is not an option.

Allard has two different versions of his firmware
    https://github.com/amunters

Once the stock rig is working, try Allard's bitx40 firmware.
You should at least add the Function button, and remove C91 an C92  as he suggests.
This will allow you to choose either a low side VFO for LSB or a high side VFO for USB.

For example, assume we are receiving at 7.2mhz
The crystal filter is centered at 11.997mhz
The crystal controlled BFO is perhaps at 11.9975mhz.
The VFO is at 11.9975 - 7.2 = 4.7975mhz, and we get LowerSideBand
To flip to upper sideband, the VFO moves to 11.9975 + 7.2 = 19.1975mhz and the BFO stays put.

Here's a a few old posts describing what is happening 
    https://groups.io/g/BITX20/message/24724
    https://groups.io/g/BITX20/message/26707?p=,,,20,0,0,0::Created,,24724,20,2,0,5050215
    https://groups.io/g/BITX20/message/25360

You may someday wish to try Allard's bitx40-raduino-v2 firmware.
This will require a few minor mods, but driving the BFO from the si5351
gives much more control over the rig.
In particular, it allows you to flip sidebands by moving the BFO down a few khz to the other side
of the crystal filter, the VFO staying put.

Jack will find that making the Bitx40 work on 20m is a significant bit of work.
Much more involved than just changng the firmware.
You will need new firmware, new filter at L1,L2,3,  also a new filter at L6,L7.
Also the board is not laid out well for 14mhz, so the power amp won't deliver much.
Good luck sorting all that out, though it has been done.

Jerry, KE7ER


On Fri, Aug 17, 2018 at 05:31 PM, Timothy Fidler wrote:
JM there is a whole lot of information here around this BBS in various corners.  see right down bottom of this post...
(public version of post sent privately a while back) 
Extra filters can come from Kees Talen who sells little PCBs for this purpose .  Moto appn note AN267 is  your friend for this design.  KT sells parts .. you do the design.

you will need to change out the IRF PA for a  proper Mitsi HF or VHF Mosfet. The pinouts don.'t align as Flowers found out but he worked out a kludge - eg wiring the RF transformer direct to the drain of the RDHH16.  The fact that the  Source and tab on the RDHH16 and 15 Mosfets are the same simplifies some of the rework and of course makes heat sinking a lot easier. Those Mosfets are avail at reasonable prices as in just over 5 usd plus freight from "cecil the parts place". DIZ,  the toroid king used to stock them but >....no more.

  There is a V2 version two that involves hardware mods- BEWARE.  Best have a backup plan like a second Raduino or a clone so you can always fall back to plan A.
 
https://github.com/amunters/bitx40   is a new load of software that may do many things you want. It also contains a whole lot of fixes and includes CW capability.

In terms of display for both 40 and 20 m with a dual band design (??)  this item (search for 6 digit freq counter) from www.mpja.com might solve your problem $13 USD without a recode job. you use the frequency counter in native mode to display frequency in 20m operation and the original Bitx display for 40 m operation  (sounded like a good idea at the time ).

Type 43 material is pretty lossy above  7 Mhz.(can forward data) there are magnetics which if you change  them out will make a difference.   Flowers got 6W out he says with only the Mosfet change.  Without that change he was getting less than 2 W out.

MOtorola design note AN267 is your friend for  designing the New output filter.  (Kees supplies parts not designs)
===============================================================================
With six watts you can drive plenty of amps that will give you 50W+  out 

https://www.youtube.com/watch?v=Ki_z6dl9xgo&t=263s

Just The guts of this amp come up from time to time on Ebay as just PCBs all ready to go but no case  for region of $80 USD. It uses an MRF-186 dual RF mosfet  ..beware imitations esp beware of SMPS mosfet kits .  Crude as hell but it works and is hard to kill it seems. Somebody in PRC obviously lucked into a whole lot of surplus Motorola parts at bargain prices

There are some reviews of it on Austr. websites./blogsites 
======================================================================================

https://groups.io/g/BITX20/topic/bitx40_convert_to_20_meters/5162026?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,5162026

MadRadioModder
 

“It’s a competent enough device assuming the circuit around it is correct.”  Therein lies the rub.  The IRF510 requires more attentive circuitry around it to offset Miller capacitance effect than a nicely designed RF transistor like the RD15VHF1… So some of that “noise” may be backed up by theory.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of ajparent1/KB1GMX
Sent: Friday, August 17, 2018 8:56 PM
To: BITX20@groups.io
Subject: Re: [BITX20] #bitx40help BITX40 LSB Winlink

 

First the code (Arduino sketch)had to be changes to set the 5351 to the needed range for 20M.
That is both the LO and the BFO as needed.  You will need the 40M sketch to do that.

The 40M band pass filter gets changed to 20M, Look for the schematic of the older bitx20
series for values.

Then the 40M low pass filter needs to be changed.

Ignore any noise about changing the IRF510s.  I have run those to over 70mhz at 
high power (20W at 13.8V).   Its a competent enough device assuming the circuit
around it is correct.

>>The magic is in the ladder/BFO combination, which shears off the carrier and unwanted sideband, while passing the wanted sideband.  

Only half true.  The balanced modulator is to remove the carrier, the filter passes the desired
sideband (strips the other).

Allison


Virus-free. www.avg.com

--

…_. _._

ajparent1/KB1GMX
 

MadRadioModeler,

Actually the Miller capacitance (drain to gate) of the RD16HHF is about in the same
(about half that of IRF510).  The RD15VHF1 is a VHF part and has even lower 
reverse Capacitance than RD16HHF.  Compared to MRF137, not impressive
just cheaper.

You are however right, that if badly designed it can be come significant.

The most common issue is to assume the input of the MOSFET is infinite
and it is, at DC only!   At RF its a complex series capacitance, resistance
and inductance.  That also means the driver circuit must deliver RF to a
complex load that is typically reactive (capacitive to about 180pf).  It
also requires maintaining gate circuit impedance low enough so that
the Drain-Gate capacitance is not a negative feedback of uncontrolled
significance (miller effect).  

If one designs using IRF510 and treats it like a RF part an amp like I have
in my hands that is flat gain and power (1db) from 2 to over 30mhz at 10W
is not only possible but also is well behaved with excellent stability.  An
example of this is the work of IK4AUY (and others). 

Look at the picture at http://ik4auy.xoom.it/article_4_english.htm

What to I mean by treated as an RF part?  The IRF510 has significant gain
to well past 70mhz.  Its power out is the product of power delivered to the
gate and can easily exceeds 13db even at 50mhz.  So hanging it on full
length leads for example is a really bad thing to do.  That means treating
it like a VHF device.  The board has to be made just like one would for any
high power amp.  That means wide traces (not barely 30mils), ample
grounding and large numbers of vias (stitching) to link topside ground
the back side ground.

It helps to have a driver that doesn't go flat on its face at mid HF.  After all
Its hard to amp up 100mW when your expecting more than 400mw or so.

Failure to do so with any device with gain at VHF usually results in instability,
low gain, and parts sensitivity.  

Allison

MadRadioModder
 

So this 1db flat gain and power from the reference?  I’m sure it can be done by doing some compensation at the gate…

 

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of ajparent1/KB1GMX
Sent: Saturday, August 18, 2018 1:39 PM
To: BITX20@groups.io
Subject: Re: [BITX20] #bitx40help BITX40 LSB Winlink

 

MadRadioModeler,

Actually the Miller capacitance (drain to gate) of the RD16HHF is about in the same
(about half that of IRF510).  The RD15VHF1 is a VHF part and has even lower 
reverse Capacitance than RD16HHF.  Compared to MRF137, not impressive
just cheaper.

You are however right, that if badly designed it can be come significant.

The most common issue is to assume the input of the MOSFET is infinite
and it is, at DC only!   At RF its a complex series capacitance, resistance
and inductance.  That also means the driver circuit must deliver RF to a
complex load that is typically reactive (capacitive to about 180pf).  It
also requires maintaining gate circuit impedance low enough so that
the Drain-Gate capacitance is not a negative feedback of uncontrolled
significance (miller effect).  

If one designs using IRF510 and treats it like a RF part an amp like I have
in my hands that is flat gain and power (1db) from 2 to over 30mhz at 10W
is not only possible but also is well behaved with excellent stability.  An
example of this is the work of IK4AUY (and others). 

Look at the picture at http://ik4auy.xoom.it/article_4_english.htm

What to I mean by treated as an RF part?  The IRF510 has significant gain
to well past 70mhz.  Its power out is the product of power delivered to the
gate and can easily exceeds 13db even at 50mhz.  So hanging it on full
length leads for example is a really bad thing to do.  That means treating
it like a VHF device.  The board has to be made just like one would for any
high power amp.  That means wide traces (not barely 30mils), ample
grounding and large numbers of vias (stitching) to link topside ground
the back side ground.

It helps to have a driver that doesn't go flat on its face at mid HF.  After all
Its hard to amp up 100mW when your expecting more than 400mw or so.

Failure to do so with any device with gain at VHF usually results in instability,
low gain, and parts sensitivity.  

Allison


Virus-free. www.avg.com

--

…_. _._

ajparent1/KB1GMX
 

With feedback.

You should see the amp for the QRPlabs QSX.. makes that look pitiful.

Allison

Daniel Crane
 

It's working!  An RMS in Reno 563 km away took my call and forwarded my email.  What I've done since posting my request in March was,
switch to USB via Allard's sketch as you all recommended and
calibrate my VFO off a web SDR (of unknown calibration but it nailed the RMS, centerline). 

I'll post my configuration next.

Thanks to all,
Dan KM6GRV